Bundle URIs II: git clone --bundle-uri

This is the second series building the bundle URI feature as discussed in the previous series that added the design document [1]. This series does not modify the design document, so the patches are independent and can be applied to the latest 'master'.

[1]
https://lore.kernel.org/git/[email protected]

This series brings in just enough logic that we can bootstrap clones from a single bundle using git clone --bundle-uri=<X>.

* Patch 1 adds a 'get' capability to 'git remote-https' which allows downloading the contents of a URI to a local file.
* Patch 2 creates basic file-copy logic within a new bundle-uri.c file. It is not used until patch 3.
* Patch 3 creates the git clone --bundle-uri=<X> option, allowing Git to bootstrap a clone from a bundle, but get the remaining objects from the origin URL. (As of this patch, it only accepts a filename.)
* Patch 4 extends the git clone --bundle-uri=<X> option to allow file:// and https:// URIs.
* Patch 5 is a CLI helper to avoid using --bundle-uri and --depth at the same time in git clone.

As outlined in [1], the next steps after this are:

1. Allow parsing a bundle list as a config file at the given URI. The key-value format is unified with the protocol v2 verb (coming in (3)).
[2]
2. Implement the protocol v2 verb, re-using the bundle list logic from (2). Use this to auto-discover bundle URIs during 'git clone' (behind a config option). [3]
3. Implement the 'creationToken' heuristic, allowing incremental 'git fetch' commands to download a bundle list from a configured URI, and only download bundles that are new based on the creation token values.
[4]

I have prepared some of this work as pull requests on my personal fork so curious readers can look ahead to where we are going:

[2] https://github.com/derrickstolee/git/pull/20

[3] https://github.com/derrickstolee/git/pull/21

[4] https://github.com/derrickstolee/git/pull/22

Note: this series includes some code pulled out of the first series [1], and in particular the git fetch --bundle-uri=<X> option is removed. The intention was to replace that with git bundle fetch <X>, but that conflicts with the work to refactor how subcommands are parsed. The git bundle fetch subcommand could be added later for maximum flexibility on the client side, but we can also move forward without it.

Thanks, -Stolee

P.S. Here is the range-diff compared to v2 of the previous bundle URI series:

1:  d444042dc4dcc < -:  ------------- docs: document bundle URI standard
2:  0a2cf60437f78 ! 1:  40808e92afb7b remote-curl: add 'get' capability
    @@ remote-curl.c: static void parse_fetch(struct strbuf *buf)
      
     +static void parse_get(struct strbuf *buf)
     +{
    -+	struct http_get_options opts = { 0 };
     +	struct strbuf url = STRBUF_INIT;
     +	struct strbuf path = STRBUF_INIT;
     +	const char *p, *space;
    @@ remote-curl.c: static void parse_fetch(struct strbuf *buf)
     +	strbuf_add(&url, p, space - p);
     +	strbuf_addstr(&path, space + 1);
     +
    -+	if (http_get_file(url.buf, path.buf, &opts))
    ++	if (http_get_file(url.buf, path.buf, NULL))
     +		die(_("failed to download file at URL '%s'"), url.buf);
     +
     +	strbuf_release(&url);
    @@ t/t5557-http-get.sh (new)
     +	get $url file1
     +	EOF
     +
    -+	test_must_fail git remote-http $url $url <input 2>err &&
    ++	test_must_fail git remote-http $url <input 2>err &&
     +	test_path_is_missing file1 &&
     +	grep "failed to download file at URL" err &&
     +	rm file1.temp
    @@ t/t5557-http-get.sh (new)
     +
     +	EOF
     +
    -+	GIT_TRACE2_PERF=1 git remote-http $url $url <input &&
    ++	GIT_TRACE2_PERF=1 git remote-http $url <input &&
     +	test_cmp "$HTTPD_DOCUMENT_ROOT_PATH/exists.txt" file2
     +'
     +
     +test_done
    -
    - ## transport-helper.c ##
    -@@ transport-helper.c: struct helper_data {
    - 		check_connectivity : 1,
    - 		no_disconnect_req : 1,
    - 		no_private_update : 1,
    --		object_format : 1;
    -+		object_format : 1,
    -+		get : 1;
    - 
    - 	/*
    - 	 * As an optimization, the transport code may invoke fetch before
    -@@ transport-helper.c: static struct child_process *get_helper(struct transport *transport)
    - 			data->no_private_update = 1;
    - 		} else if (starts_with(capname, "object-format")) {
    - 			data->object_format = 1;
    -+		} else if (!strcmp(capname, "get")) {
    -+			data->get = 1;
    - 		} else if (mandatory) {
    - 			die(_("unknown mandatory capability %s; this remote "
    - 			      "helper probably needs newer version of Git"),
3:  abec47564fd9c ! 2:  7d3159f0d9a29 bundle-uri: create basic file-copy logic
    @@ Commit message
         file, not a bundle list. Bundle lists will be implemented in a future
         change.
     
    +    Note that the discovery of a temporary filename is slightly racy because
    +    the odb_mkstemp() relies on the temporary file not existing. With the
    +    current implementation being limited to file copies, we could replace
    +    the copy_file() with copy_fd(). The tricky part comes in future changes
    +    that send the filename to 'git remote-https' and its 'get' capability.
    +    At that point, we need the file descriptor closed _and_ the file
    +    unlinked. If we were to keep the file descriptor open for the sake of
    +    normal file copies, then we would pollute the rest of the code for
    +    little benefit. This is especially the case because we expect that most
    +    bundle URI use will be based on HTTPS instead of file copies.
    +
         Signed-off-by: Derrick Stolee <[email protected]>
     
      ## Makefile ##
    @@ bundle-uri.c (new)
     +#include "refs.h"
     +#include "run-command.h"
     +
    -+static void find_temp_filename(struct strbuf *name)
    ++static int find_temp_filename(struct strbuf *name)
     +{
     +	int fd;
     +	/*
    @@ bundle-uri.c (new)
     +	 * racy, but unlikely to collide.
     +	 */
     +	fd = odb_mkstemp(name, "bundles/tmp_uri_XXXXXX");
    -+	if (fd < 0)
    -+		die(_("failed to create temporary file"));
    ++	if (fd < 0) {
    ++		warning(_("failed to create temporary file"));
    ++		return -1;
    ++	}
    ++
     +	close(fd);
     +	unlink(name->buf);
    ++	return 0;
     +}
     +
    -+static int copy_uri_to_file(const char *uri, const char *file)
    ++static int copy_uri_to_file(const char *file, const char *uri)
     +{
    -+	/* Copy as a file */
    -+	return copy_file(file, uri, 0444);
    ++	/* File-based URIs only for now. */
    ++	return copy_file(file, uri, 0);
     +}
     +
     +static int unbundle_from_file(struct repository *r, const char *file)
    @@ bundle-uri.c (new)
     +	int result = 0;
     +	int bundle_fd;
     +	struct bundle_header header = BUNDLE_HEADER_INIT;
    -+	struct strvec extra_index_pack_args = STRVEC_INIT;
     +	struct string_list_item *refname;
     +	struct strbuf bundle_ref = STRBUF_INIT;
     +	size_t bundle_prefix_len;
    @@ bundle-uri.c (new)
     +	if ((bundle_fd = read_bundle_header(file, &header)) < 0)
     +		return 1;
     +
    -+	if ((result = unbundle(r, &header, bundle_fd, &extra_index_pack_args)))
    ++	if ((result = unbundle(r, &header, bundle_fd, NULL)))
     +		return 1;
     +
     +	/*
    @@ bundle-uri.c (new)
     +	int result = 0;
     +	struct strbuf filename = STRBUF_INIT;
     +
    -+	find_temp_filename(&filename);
    -+	if ((result = copy_uri_to_file(uri, filename.buf)))
    ++	if ((result = find_temp_filename(&filename)))
    ++		goto cleanup;
    ++
    ++	if ((result = copy_uri_to_file(filename.buf, uri))) {
    ++		warning(_("failed to download bundle from URI '%s'"), uri);
     +		goto cleanup;
    ++	}
     +
    -+	if ((result = !is_bundle(filename.buf, 0)))
    ++	if ((result = !is_bundle(filename.buf, 0))) {
    ++		warning(_("file at URI '%s' is not a bundle"), uri);
     +		goto cleanup;
    ++	}
     +
    -+	if ((result = unbundle_from_file(r, filename.buf)))
    ++	if ((result = unbundle_from_file(r, filename.buf))) {
    ++		warning(_("failed to unbundle bundle from URI '%s'"), uri);
     +		goto cleanup;
    ++	}
     +
     +cleanup:
     +	unlink(filename.buf);
4:  f6255ec518857 < -:  ------------- fetch: add --bundle-uri option
-:  ------------- > 3:  29e645a54ba7f clone: add --bundle-uri option
5:  bfbd11b48bf1b ! 4:  f6bc3177332e8 bundle-uri: add support for http(s):// and file://
    @@ Metadata
      ## Commit message ##
         bundle-uri: add support for http(s):// and file://
     
    -    The previous change created the 'git fetch --bundle-uri=<uri>' option.
    +    The previous change created the 'git clone --bundle-uri=<uri>' option.
         Currently, <uri> must be a filename.
     
         Update copy_uri_to_file() to first inspect the URI for an HTTP(S) prefix
    @@ Commit message
         Signed-off-by: Derrick Stolee <[email protected]>
     
      ## bundle-uri.c ##
    -@@ bundle-uri.c: static void find_temp_filename(struct strbuf *name)
    - 	unlink(name->buf);
    +@@ bundle-uri.c: static int find_temp_filename(struct strbuf *name)
    + 	return 0;
      }
      
    -+static int download_https_uri_to_file(const char *uri, const char *file)
    -+{
    +-static int copy_uri_to_file(const char *file, const char *uri)
    ++static int download_https_uri_to_file(const char *file, const char *uri)
    + {
    +-	/* File-based URIs only for now. */
    +-	return copy_file(file, uri, 0);
     +	int result = 0;
     +	struct child_process cp = CHILD_PROCESS_INIT;
     +	FILE *child_in = NULL, *child_out = NULL;
    @@ bundle-uri.c: static void find_temp_filename(struct strbuf *name)
     +	return result;
     +}
     +
    - static int copy_uri_to_file(const char *uri, const char *file)
    - {
    ++static int copy_uri_to_file(const char *filename, const char *uri)
    ++{
     +	const char *out;
    ++
     +	if (skip_prefix(uri, "https:", &out) ||
     +	    skip_prefix(uri, "http:", &out))
    -+		return download_https_uri_to_file(uri, file);
    ++		return download_https_uri_to_file(filename, uri);
     +
     +	if (!skip_prefix(uri, "file://", &out))
     +		out = uri;
     +
    - 	/* Copy as a file */
    --	return copy_file(file, uri, 0444);
    -+	return !!copy_file(file, out, 0);
    ++	/* Copy as a file */
    ++	return copy_file(filename, out, 0);
      }
      
      static int unbundle_from_file(struct repository *r, const char *file)
     
    - ## t/t5558-fetch-bundle-uri.sh ##
    -@@ t/t5558-fetch-bundle-uri.sh: test_expect_success 'fetch file bundle' '
    + ## t/t5558-clone-bundle-uri.sh ##
    +@@ t/t5558-clone-bundle-uri.sh: test_expect_success 'clone with path bundle' '
          test_cmp expect actual
      '
      
    -+test_expect_success 'fetch file:// bundle' '
    -+	git init fetch-file &&
    -+	git -C fetch-file fetch --bundle-uri="file://$(pwd)/fetch-from/B.bundle" &&
    -+	git -C fetch-file rev-parse refs/bundles/topic >actual &&
    -+	git -C fetch-from rev-parse topic >expect &&
    ++test_expect_success 'clone with file:// bundle' '
    ++	git clone --bundle-uri="file://$(pwd)/clone-from/B.bundle" \
    ++		clone-from clone-file &&
    ++	git -C clone-file rev-parse refs/bundles/topic >actual &&
    ++	git -C clone-from rev-parse topic >expect &&
     +	test_cmp expect actual
     +'
     +
    @@ t/t5558-fetch-bundle-uri.sh: test_expect_success 'fetch file bundle' '
     +start_httpd
     +
     +test_expect_success 'fail to fetch from non-existent HTTP URL' '
    -+	test_must_fail git fetch --bundle-uri="$HTTPD_URL/does-not-exist" 2>err &&
    ++	test_when_finished rm -rf test &&
    ++	git clone --bundle-uri="$HTTPD_URL/does-not-exist" . test 2>err &&
     +	grep "failed to download bundle from URI" err
     +'
     +
     +test_expect_success 'fail to fetch from non-bundle HTTP URL' '
    ++	test_when_finished rm -rf test &&
     +	echo bogus >"$HTTPD_DOCUMENT_ROOT_PATH/bogus" &&
    -+	test_must_fail git fetch --bundle-uri="$HTTPD_URL/bogus" 2>err &&
    ++	git clone --bundle-uri="$HTTPD_URL/bogus" . test 2>err &&
     +	grep "is not a bundle" err
     +'
     +
    -+test_expect_success 'fetch HTTP bundle' '
    -+	cp fetch-from/B.bundle "$HTTPD_DOCUMENT_ROOT_PATH/B.bundle" &&
    -+	git init fetch-http &&
    -+	git -C fetch-http fetch --bundle-uri="$HTTPD_URL/B.bundle" &&
    -+	git -C fetch-http rev-parse refs/bundles/topic >actual &&
    -+	git -C fetch-from rev-parse topic >expect &&
    -+	test_cmp expect actual
    ++test_expect_success 'clone HTTP bundle' '
    ++	cp clone-from/B.bundle "$HTTPD_DOCUMENT_ROOT_PATH/B.bundle" &&
    ++
    ++	git clone --no-local --mirror clone-from \
    ++		"$HTTPD_DOCUMENT_ROOT_PATH/fetch.git" &&
    ++
    ++	git clone --bundle-uri="$HTTPD_URL/B.bundle" \
    ++		"$HTTPD_URL/smart/fetch.git" clone-http &&
    ++	git -C clone-http rev-parse refs/bundles/topic >actual &&
    ++	git -C clone-from rev-parse topic >expect &&
    ++	test_cmp expect actual &&
    ++
    ++	test_config -C clone-http log.excludedecoration refs/bundle/
     +'
     +
     +# Do not add tests here unless they use the HTTP server, as they will
6:  a217e9a0640b4 < -:  ------------- fetch: add 'refs/bundle/' to log.excludeDecoration
-:  ------------- > 5:  e823b168ab725 clone: --bundle-uri cannot be combined with --depth

Derrick Stolee (5):
remote-curl: add 'get' capability
bundle-uri: create basic file-copy logic
clone: add --bundle-uri option
bundle-uri: add support for http(s):// and file://
clone: --bundle-uri cannot be combined with --depth

 Documentation/git-clone.txt         |   7 ++
 Documentation/gitremote-helpers.txt |   9 ++
 Makefile                            |   1 +
 builtin/clone.c                     |  18 +++
 bundle-uri.c                        | 168 ++++++++++++++++++++++++++++
 bundle-uri.h                        |  14 +++
 remote-curl.c                       |  32 ++++++
 t/t5557-http-get.sh                 |  37 ++++++
 t/t5558-clone-bundle-uri.sh         |  81 ++++++++++++++
 t/t5606-clone-options.sh            |   8 ++
 10 files changed, 375 insertions(+)
 create mode 100644 bundle-uri.c
 create mode 100644 bundle-uri.h
 create mode 100755 t/t5557-http-get.sh
 create mode 100755 t/t5558-clone-bundle-uri.sh

base-commit: e72d93e88cb20b06e88e6e7d81bd1dc4effe453f
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1300%2Fderrickstolee%2Fbundle-redo%2Fclone-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1300/derrickstolee/bundle-redo/clone-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1300

gitgitgadget

From: Derrick Stolee <[email protected]>

A future change will want a way to download a file over HTTP(S) using the simplest of download mechanisms. We do not want to assume that the server on the other side understands anything about the Git protocol but could be a simple static web server.

Create the new 'get' capability for the remote helpers which advertises that the 'get' command is avalable. A caller can send a line containing 'get <url> <path>' to download the file at <url> into the file at <path>.

---
 Documentation/gitremote-helpers.txt |  9 +++++++
 remote-curl.c                       | 32 +++++++++++++++++++++++++
 t/t5557-http-get.sh                 | 37 +++++++++++++++++++++++++++++
 3 files changed, 78 insertions(+)
 create mode 100755 t/t5557-http-get.sh

index 6f1e269ae43..ed8da428c98 100644
@@ -168,6 +168,9 @@ Supported commands: 'list', 'import'.
 	Can guarantee that when a clone is requested, the received
 	pack is self contained and is connected.
 
+'get'::
+	Can use the 'get' command to download a file from a given URI.
+
 If a helper advertises 'connect', Git will use it if possible and
 fall back to another capability if the helper requests so when
 connecting (see the 'connect' command under COMMANDS).

@@ -418,6 +421,12 @@ Supported if the helper has the "connect" capability.
 +
 Supported if the helper has the "stateless-connect" capability.
 
+'get' <uri> <path>::
+	Downloads the file from the given `<uri>` to the given `<path>`. If
+	`<path>.temp` exists, then Git assumes that the `.temp` file is a
+	partial download from a previous attempt and will resume the
+	download from that position.
+
 If a fatal error occurs, the program writes the error message to
 stderr and exits. The caller should expect that a suitable error
 message has been printed if the child closes the connection without

index b8758757ece..73fbdbddd84 100644
@@ -1286,6 +1286,33 @@ static void parse_fetch(struct strbuf *buf)
 	strbuf_reset(buf);
 }
 
+static void parse_get(struct strbuf *buf)
+{
+	struct strbuf url = STRBUF_INIT;
+	struct strbuf path = STRBUF_INIT;
+	const char *p, *space;
+
+	if (!skip_prefix(buf->buf, "get ", &p))
+		die(_("http transport does not support %s"), buf->buf);
+
+	space = strchr(p, ' ');
+
+	if (!space)
+		die(_("protocol error: expected '<url> <path>', missing space"));
+
+	strbuf_add(&url, p, space - p);
+	strbuf_addstr(&path, space + 1);
+
+	if (http_get_file(url.buf, path.buf, NULL))
+		die(_("failed to download file at URL '%s'"), url.buf);
+
+	strbuf_release(&url);
+	strbuf_release(&path);
+	printf("\n");
+	fflush(stdout);
+	strbuf_reset(buf);
+}
+
 static int push_dav(int nr_spec, const char **specs)
 {
 	struct child_process child = CHILD_PROCESS_INIT;

@@ -1564,9 +1591,14 @@ int cmd_main(int argc, const char **argv)
 				printf("unsupported\n");
 			fflush(stdout);
 
+		} else if (skip_prefix(buf.buf, "get ", &arg)) {
+			parse_get(&buf);
+			fflush(stdout);
+
 		} else if (!strcmp(buf.buf, "capabilities")) {
 			printf("stateless-connect\n");
 			printf("fetch\n");
+			printf("get\n");
 			printf("option\n");
 			printf("push\n");
 			printf("check-connectivity\n");

new file mode 100755
index 00000000000..50b7dbcf957
@@ -0,0 +1,37 @@
+#!/bin/sh
+
+test_description='test downloading a file by URL'
+
+. ./test-lib.sh
+
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+test_expect_success 'get by URL: 404' '
+	url="$HTTPD_URL/none.txt" &&
+	cat >input <<-EOF &&
+	capabilities
+	get $url file1
+	EOF
+
+	test_must_fail git remote-http $url <input 2>err &&
+	test_path_is_missing file1 &&
+	grep "failed to download file at URL" err &&
+	rm file1.temp
+'
+
+test_expect_success 'get by URL: 200' '
+	echo data >"$HTTPD_DOCUMENT_ROOT_PATH/exists.txt" &&
+
+	url="$HTTPD_URL/exists.txt" &&
+	cat >input <<-EOF &&
+	capabilities
+	get $url file2
+
+	EOF
+
+	GIT_TRACE2_PERF=1 git remote-http $url <input &&
+	test_cmp "$HTTPD_DOCUMENT_ROOT_PATH/exists.txt" file2
+'
+
+test_done

gitgitgadget

Add a:

TEST_PASSES_SANITIZE_LEAK=true

Before:

I trust this is important for your series that flags tests that _could_ pass with this. Thanks.

Yes. Thanks.

Good eye. Removed.

Thanks,
-Stolee

Not really, it does add a "check" mode, and this is one of the few tests crop up when merged with "seen" if run in that mode, but currentlny it's only run manually, and we have other outstanding deviations.

It's just something for "master": We have the "linux-leaks" job for a while now, so it makes sense for new tests to declare if they're leak-free or not, so we guard against the introduction of leaks with new code, if possible.

I (or someone else) can always follow-up with something like[1], but as it's easy it makes sense to just add it in the first place, thanks.

1. https://lore.kernel.org/git/[email protected]/

From: Derrick Stolee <[email protected]>

Before implementing a way to fetch bundles into a repository, create the basic logic. Assume that the URI is actually a file path. Future logic will make this more careful to other protocols.

For now, we also only succeed if the content at the URI is a bundle file, not a bundle list. Bundle lists will be implemented in a future change.

Note that the discovery of a temporary filename is slightly racy because the odb_mkstemp() relies on the temporary file not existing. With the current implementation being limited to file copies, we could replace the copy_file() with copy_fd(). The tricky part comes in future changes that send the filename to 'git remote-https' and its 'get' capability. At that point, we need the file descriptor closed _and_ the file unlinked. If we were to keep the file descriptor open for the sake of normal file copies, then we would pollute the rest of the code for little benefit. This is especially the case because we expect that most bundle URI use will be based on HTTPS instead of file copies.

---
 Makefile     |   1 +
 bundle-uri.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++
 bundle-uri.h |  14 +++++++
 3 files changed, 119 insertions(+)
 create mode 100644 bundle-uri.c
 create mode 100644 bundle-uri.h

index 1624471badc..7d5f48069ea 100644
@@ -906,6 +906,7 @@ LIB_OBJS += blob.o
 LIB_OBJS += bloom.o
 LIB_OBJS += branch.o
 LIB_OBJS += bulk-checkin.o
+LIB_OBJS += bundle-uri.o
 LIB_OBJS += bundle.o
 LIB_OBJS += cache-tree.o
 LIB_OBJS += cbtree.o

new file mode 100644
index 00000000000..8a152f1ef14
@@ -0,0 +1,14 @@
+#ifndef BUNDLE_URI_H
+#define BUNDLE_URI_H
+
+struct repository;
+
+/**
+ * Fetch data from the given 'uri' and unbundle the bundle data found
+ * based on that information.
+ *
+ * Returns non-zero if no bundle information is found at the given 'uri'.
+ */
+int fetch_bundle_uri(struct repository *r, const char *uri);
+
+#endif

gitgitgadget

Ahh, it looks like this was the point I missed in my previous review. IIUC, we need the file unlinked because http_get_file() will eventually call finalize_object_file() to move a tempfile to the final object name, and that will fail if we have an empty file already in place.

Yes, and I also was not sure what would happen if the empty file existed. I tested it and thought allowing overwriting an existing file would be a bigger problem than this choice of a filename.

We also discussed options about how it would be nice to have a predictable filename so we could resume downloads _across Git process failures_ instead of just a network failure within a single Git process. This is something to explore when creating that functionality.

Thanks,
-Stolee

From: Derrick Stolee <[email protected]>

Cloning a remote repository is one of the most expensive operations in Git. The server can spend a lot of CPU time generating a pack-file for the client's request. The amount of data can clog the network for a long time, and the Git protocol is not resumable. For users with poor network connections or are located far away from the origin server, this can be especially painful.

Add a new '--bundle-uri' option to 'git clone' to bootstrap a clone from a bundle. If the user is aware of a bundle server, then they can tell Git to bootstrap the new repository with these bundles before fetching the remaining objects from the origin server.

---
 Documentation/git-clone.txt |  6 ++++++
 builtin/clone.c             | 15 +++++++++++++++
 t/t5558-clone-bundle-uri.sh | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100755 t/t5558-clone-bundle-uri.sh

index 632bd1348ea..60fedf7eb5e 100644
@@ -323,6 +323,12 @@ or `--mirror` is given)
 	for `host.xz:foo/.git`).  Cloning into an existing directory
 	is only allowed if the directory is empty.
 
+--bundle-uri=<uri>::
+	Before fetching from the remote, fetch a bundle from the given
+	`<uri>` and unbundle the data into the local repository. The refs
+	in the bundle will be stored under the hidden `refs/bundle/*`
+	namespace.
+
 :git-clone: 1
 include::urls.txt[]
 

index c4ff4643ecd..4224d562758 100644
@@ -34,6 +34,7 @@
 #include "list-objects-filter-options.h"
 #include "hook.h"
 #include "bundle.h"
+#include "bundle-uri.h"
 
 /*
  * Overall FIXMEs:

@@ -77,6 +78,7 @@ static int option_filter_submodules = -1;    /* unspecified */
 static int config_filter_submodules = -1;    /* unspecified */
 static struct string_list server_options = STRING_LIST_INIT_NODUP;
 static int option_remote_submodules;
+static const char *bundle_uri;
 
 static int recurse_submodules_cb(const struct option *opt,
 				 const char *arg, int unset)

@@ -160,6 +162,8 @@ static struct option builtin_clone_options[] = {
 		    N_("any cloned submodules will use their remote-tracking branch")),
 	OPT_BOOL(0, "sparse", &option_sparse_checkout,
 		    N_("initialize sparse-checkout file to include only files at root")),
+	OPT_STRING(0, "bundle-uri", &bundle_uri,
+		   N_("uri"), N_("a URI for downloading bundles before fetching from origin remote")),
 	OPT_END()
 };
 

@@ -1232,6 +1236,17 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	if (transport->smart_options && !deepen && !filter_options.choice)
 		transport->smart_options->check_self_contained_and_connected = 1;
 
+	/*
+	 * Before fetching from the remote, download and install bundle
+	 * data from the --bundle-uri option.
+	 */
+	if (bundle_uri) {
+		/* At this point, we need the_repository to match the cloned repo. */
+		repo_init(the_repository, git_dir, work_tree);
+		if (fetch_bundle_uri(the_repository, bundle_uri))
+			warning(_("failed to fetch objects from bundle URI '%s'"),
+				bundle_uri);
+	}
 
 	strvec_push(&transport_ls_refs_options.ref_prefixes, "HEAD");
 	refspec_ref_prefixes(&remote->fetch,

new file mode 100755
index 00000000000..f709bcb729c
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+test_description='test fetching bundles with --bundle-uri'
+
+. ./test-lib.sh
+
+test_expect_success 'fail to clone from non-existent file' '
+	test_when_finished rm -rf test &&
+	git clone --bundle-uri="$(pwd)/does-not-exist" . test 2>err &&
+	grep "failed to download bundle from URI" err
+'
+
+test_expect_success 'fail to clone from non-bundle file' '
+	test_when_finished rm -rf test &&
+	echo bogus >bogus &&
+	git clone --bundle-uri="$(pwd)/bogus" . test 2>err &&
+	grep "is not a bundle" err
+'
+
+test_expect_success 'create bundle' '
+	git init clone-from &&
+	git -C clone-from checkout -b topic &&
+	test_commit -C clone-from A &&
+	test_commit -C clone-from B &&
+	git -C clone-from bundle create B.bundle topic
+'
+
+test_expect_success 'clone with path bundle' '
+	git clone --bundle-uri="clone-from/B.bundle" \
+		clone-from clone-path &&
+	git -C clone-path rev-parse refs/bundles/topic >actual &&
+	git -C clone-from rev-parse topic >expect &&
+	test_cmp expect actual
+'
+
+test_done

gitgitgadget

From: Derrick Stolee <[email protected]>

The previous change created the 'git clone --bundle-uri=<uri>' option. Currently, <uri> must be a filename.

Update copy_uri_to_file() to first inspect the URI for an HTTP(S) prefix and use git-remote-https as the way to download the data at that URI. Otherwise, check to see if file:// is present and modify the prefix accordingly.

---
 bundle-uri.c                | 70 +++++++++++++++++++++++++++++++++++--
 t/t5558-clone-bundle-uri.sh | 45 ++++++++++++++++++++++++
 2 files changed, 112 insertions(+), 3 deletions(-)

index b35babc36aa..7086382b186 100644
@@ -23,10 +23,74 @@ static int find_temp_filename(struct strbuf *name)
 	return 0;
 }
 
-static int copy_uri_to_file(const char *file, const char *uri)
+static int download_https_uri_to_file(const char *file, const char *uri)
 {
-	/* File-based URIs only for now. */
-	return copy_file(file, uri, 0);
+	int result = 0;
+	struct child_process cp = CHILD_PROCESS_INIT;
+	FILE *child_in = NULL, *child_out = NULL;
+	struct strbuf line = STRBUF_INIT;
+	int found_get = 0;
+
+	strvec_pushl(&cp.args, "git-remote-https", "origin", uri, NULL);
+	cp.in = -1;
+	cp.out = -1;
+
+	if (start_command(&cp))
+		return 1;
+
+	child_in = fdopen(cp.in, "w");
+	if (!child_in) {
+		result = 1;
+		goto cleanup;
+	}
+
+	child_out = fdopen(cp.out, "r");
+	if (!child_out) {
+		result = 1;
+		goto cleanup;
+	}
+
+	fprintf(child_in, "capabilities\n");
+	fflush(child_in);
+
+	while (!strbuf_getline(&line, child_out)) {
+		if (!line.len)
+			break;
+		if (!strcmp(line.buf, "get"))
+			found_get = 1;
+	}
+	strbuf_release(&line);
+
+	if (!found_get) {
+		result = error(_("insufficient capabilities"));
+		goto cleanup;
+	}
+
+	fprintf(child_in, "get %s %s\n\n", uri, file);
+
+cleanup:
+	if (child_in)
+		fclose(child_in);
+	if (finish_command(&cp))
+		return 1;
+	if (child_out)
+		fclose(child_out);
+	return result;
+}
+
+static int copy_uri_to_file(const char *filename, const char *uri)
+{
+	const char *out;
+
+	if (skip_prefix(uri, "https:", &out) ||
+	    skip_prefix(uri, "http:", &out))
+		return download_https_uri_to_file(filename, uri);
+
+	if (!skip_prefix(uri, "file://", &out))
+		out = uri;
+
+	/* Copy as a file */
+	return copy_file(filename, out, 0);
 }
 
 static int unbundle_from_file(struct repository *r, const char *file)

gitgitgadget

Sounds good to me. Can't abandon "out" because it is used for the "file://" prefix, but istarts_with() is better here.

Thanks,
-Stolee

From: Derrick Stolee <[email protected]>

A previous change added the '--bundle-uri' option, but did not check if the --depth parameter was included. Since bundles are not compatible with shallow clones, provide an error message to the user who is attempting this combination.

I am leaving this as its own change, separate from the one that implements '--bundle-uri', because this is more of an advisory for the user. There is nothing wrong with bootstrapping with bundles and then fetching a shallow clone. However, that is likely going to involve too much work for the client _and_ the server. The client will download all of this bundle information containing the full history of the repository only to ignore most of it. The server will get a shallow fetch request, but with a list of haves that might cause a more painful computation of that shallow pack-file.

---
 Documentation/git-clone.txt | 3 ++-
 builtin/clone.c             | 3 +++
 t/t5606-clone-options.sh    | 8 ++++++++
 3 files changed, 13 insertions(+), 1 deletion(-)

index 60fedf7eb5e..d032d971dd7 100644
@@ -327,7 +327,8 @@ or `--mirror` is given)
 	Before fetching from the remote, fetch a bundle from the given
 	`<uri>` and unbundle the data into the local repository. The refs
 	in the bundle will be stored under the hidden `refs/bundle/*`
-	namespace.
+	namespace. This option is incompatible with `--depth`,
+	`--shallow-since`, and `--shallow-exclude`.
 
 :git-clone: 1
 include::urls.txt[]

index 4224d562758..4463789680b 100644
@@ -937,6 +937,9 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		option_no_checkout = 1;
 	}
 
+	if (bundle_uri && deepen)
+		die(_("--bundle-uri is incompatible with --depth, --shallow-since, and --shallow-exclude"));
+
 	repo_name = argv[0];
 
 	path = get_repo_path(repo_name, &is_bundle);

index 8f676d6b0c0..f6bb02ab947 100755
@@ -58,6 +58,14 @@ test_expect_success 'disallows --bare with --separate-git-dir' '
 
 '
 
+test_expect_success 'disallows --bundle-uri with shallow options' '
+	for option in --depth=1 --shallow-since=01-01-2000 --shallow-exclude=HEAD
+	do
+		test_must_fail git clone --bundle-uri=bundle $option from to 2>err &&
+		grep "bundle-uri is incompatible" err || return 1
+	done
+'
+
 test_expect_success 'reject cloning shallow repository' '
 	test_when_finished "rm -rf repo" &&
 	test_must_fail git clone --reject-shallow shallow-repo out 2>err &&

gitgitgadget

Looks good to me, with just one small fix and a couple of optional nitpicks. Thaks for the series!

Thanks for the review!

-Stolee

This is the second series building the bundle URI feature as discussed in the previous series that added the design document [1]. This series does not modify the design document, so the patches are independent and can be applied to the latest 'master'.

[1]
https://lore.kernel.org/git/[email protected]

This series brings in just enough logic that we can bootstrap clones from a single bundle using git clone --bundle-uri=<X>.

* Patch 1 adds a 'get' capability to 'git remote-https' which allows downloading the contents of a URI to a local file.
* Patch 2 creates basic file-copy logic within a new bundle-uri.c file. It is not used until patch 3.
* Patch 3 creates the git clone --bundle-uri=<X> option, allowing Git to bootstrap a clone from a bundle, but get the remaining objects from the origin URL. (As of this patch, it only accepts a filename.)
* Patch 4 extends the git clone --bundle-uri=<X> option to allow file:// and https:// URIs.
* Patch 5 is a CLI helper to avoid using --bundle-uri and --depth at the same time in git clone.

As outlined in [1], the next steps after this are:

1. Allow parsing a bundle list as a config file at the given URI. The key-value format is unified with the protocol v2 verb (coming in (3)).
[2]
2. Implement the protocol v2 verb, re-using the bundle list logic from (2). Use this to auto-discover bundle URIs during 'git clone' (behind a config option). [3]
3. Implement the 'creationToken' heuristic, allowing incremental 'git fetch' commands to download a bundle list from a configured URI, and only download bundles that are new based on the creation token values.
[4]

I have prepared some of this work as pull requests on my personal fork so curious readers can look ahead to where we are going:

[2] https://github.com/derrickstolee/git/pull/20

[3] https://github.com/derrickstolee/git/pull/21

[4] https://github.com/derrickstolee/git/pull/22

Note: this series includes some code pulled out of the first series [1], and in particular the git fetch --bundle-uri=<X> option is removed. The intention was to replace that with git bundle fetch <X>, but that conflicts with the work to refactor how subcommands are parsed. The git bundle fetch subcommand could be added later for maximum flexibility on the client side, but we can also move forward without it.

Updates in v2
=============

* Several typos or small tweaks. See the range-diff for details.

Thanks, -Stolee

Derrick Stolee (5):
remote-curl: add 'get' capability
bundle-uri: create basic file-copy logic
clone: add --bundle-uri option
bundle-uri: add support for http(s):// and file://
clone: --bundle-uri cannot be combined with --depth

 Documentation/git-clone.txt         |   7 ++
 Documentation/gitremote-helpers.txt |   9 ++
 Makefile                            |   1 +
 builtin/clone.c                     |  18 +++
 bundle-uri.c                        | 168 ++++++++++++++++++++++++++++
 bundle-uri.h                        |  14 +++
 remote-curl.c                       |  28 +++++
 t/t5557-http-get.sh                 |  39 +++++++
 t/t5558-clone-bundle-uri.sh         |  81 ++++++++++++++
 t/t5606-clone-options.sh            |   8 ++
 10 files changed, 373 insertions(+)
 create mode 100644 bundle-uri.c
 create mode 100644 bundle-uri.h
 create mode 100755 t/t5557-http-get.sh
 create mode 100755 t/t5558-clone-bundle-uri.sh

base-commit: e72d93e88cb20b06e88e6e7d81bd1dc4effe453f
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1300%2Fderrickstolee%2Fbundle-redo%2Fclone-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1300/derrickstolee/bundle-redo/clone-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1300

Range-diff vs v1:

1: 40808e92afb ! 1: 4df4a1d679a remote-curl: add 'get' capability

     @@ Commit message
          'get <url> <path>' to download the file at <url> into the file at
          <path>.
      
     +    Reviewed-by: Josh Steadmon <[email protected]>
          Signed-off-by: Derrick Stolee <[email protected]>
      
       ## Documentation/gitremote-helpers.txt ##
     @@ remote-curl.c: static void parse_fetch(struct strbuf *buf)
       	strbuf_reset(buf);
       }
       
     -+static void parse_get(struct strbuf *buf)
     ++static void parse_get(const char *arg)
      +{
      +	struct strbuf url = STRBUF_INIT;
      +	struct strbuf path = STRBUF_INIT;
     -+	const char *p, *space;
     ++	const char *space;
      +
     -+	if (!skip_prefix(buf->buf, "get ", &p))
     -+		die(_("http transport does not support %s"), buf->buf);
     -+
     -+	space = strchr(p, ' ');
     ++	space = strchr(arg, ' ');
      +
      +	if (!space)
      +		die(_("protocol error: expected '<url> <path>', missing space"));
      +
     -+	strbuf_add(&url, p, space - p);
     ++	strbuf_add(&url, arg, space - arg);
      +	strbuf_addstr(&path, space + 1);
      +
      +	if (http_get_file(url.buf, path.buf, NULL))
     @@ remote-curl.c: static void parse_fetch(struct strbuf *buf)
      +	strbuf_release(&path);
      +	printf("\n");
      +	fflush(stdout);
     -+	strbuf_reset(buf);
      +}
      +
       static int push_dav(int nr_spec, const char **specs)
     @@ remote-curl.c: int cmd_main(int argc, const char **argv)
       			fflush(stdout);
       
      +		} else if (skip_prefix(buf.buf, "get ", &arg)) {
     -+			parse_get(&buf);
     ++			parse_get(arg);
      +			fflush(stdout);
      +
       		} else if (!strcmp(buf.buf, "capabilities")) {
     @@ t/t5557-http-get.sh (new)
      +start_httpd
      +
      +test_expect_success 'get by URL: 404' '
     ++	test_when_finished "rm -f file.temp" &&
      +	url="$HTTPD_URL/none.txt" &&
      +	cat >input <<-EOF &&
      +	capabilities
     @@ t/t5557-http-get.sh (new)
      +
      +	test_must_fail git remote-http $url <input 2>err &&
      +	test_path_is_missing file1 &&
     -+	grep "failed to download file at URL" err &&
     -+	rm file1.temp
     ++	grep "failed to download file at URL" err
      +'
      +
      +test_expect_success 'get by URL: 200' '
     @@ t/t5557-http-get.sh (new)
      +
      +	EOF
      +
     -+	GIT_TRACE2_PERF=1 git remote-http $url <input &&
     ++	git remote-http $url <input &&
      +	test_cmp "$HTTPD_DOCUMENT_ROOT_PATH/exists.txt" file2
      +'
      +
 2:  7d3159f0d9a ! 2:  6a6f1a04889 bundle-uri: create basic file-copy logic
     @@ Commit message
          little benefit. This is especially the case because we expect that most
          bundle URI use will be based on HTTPS instead of file copies.
      
     +    Reviewed-by: Josh Steadmon <[email protected]>
          Signed-off-by: Derrick Stolee <[email protected]>
      
       ## Makefile ##
     @@ bundle-uri.h (new)
      +int fetch_bundle_uri(struct repository *r, const char *uri);
      +
      +#endif
     +
     + ## t/t5557-http-get.sh ##
     +@@
     + 
     + test_description='test downloading a file by URL'
     + 
     ++TEST_PASSES_SANITIZE_LEAK=true
     ++
     + . ./test-lib.sh
     + 
     + . "$TEST_DIRECTORY"/lib-httpd.sh

3: 29e645a54ba ! 3: 00debaf6e77 clone: add --bundle-uri option
@@ Commit message
Git to bootstrap the new repository with these bundles before fetching the remaining objects from the origin server.

+ Reviewed-by: Josh Steadmon <[email protected]>

## Documentation/git-clone.txt ##
4: f6bc3177332 ! 4: e4f2dcc7a45 bundle-uri: add support for http(s):// and file://

     @@ Commit message
          Otherwise, check to see if file:// is present and modify the prefix
          accordingly.
      
     +    Reviewed-by: Josh Steadmon <[email protected]>
          Signed-off-by: Derrick Stolee <[email protected]>
      
       ## bundle-uri.c ##
     @@ bundle-uri.c: static int find_temp_filename(struct strbuf *name)
      +{
      +	const char *out;
      +
     -+	if (skip_prefix(uri, "https:", &out) ||
     -+	    skip_prefix(uri, "http:", &out))
     ++	if (istarts_with(uri, "https:") ||
     ++	    istarts_with(uri, "http:"))
      +		return download_https_uri_to_file(filename, uri);
      +
      +	if (!skip_prefix(uri, "file://", &out))

5: e823b168ab7 ! 5: acee1fae027 clone: --bundle-uri cannot be combined with --depth
@@ Commit message
fetch request, but with a list of haves that might cause a more painful computation of that shallow pack-file.

+ Reviewed-by: Josh Steadmon <[email protected]>

## Documentation/git-clone.txt ##

gitgitgadget

From: Derrick Stolee <[email protected]>

A future change will want a way to download a file over HTTP(S) using the simplest of download mechanisms. We do not want to assume that the server on the other side understands anything about the Git protocol but could be a simple static web server.

Create the new 'get' capability for the remote helpers which advertises that the 'get' command is avalable. A caller can send a line containing 'get <url> <path>' to download the file at <url> into the file at <path>.

---
 Documentation/gitremote-helpers.txt |  9 +++++++
 remote-curl.c                       | 28 ++++++++++++++++++++++
 t/t5557-http-get.sh                 | 37 +++++++++++++++++++++++++++++
 3 files changed, 74 insertions(+)
 create mode 100755 t/t5557-http-get.sh

index 6f1e269ae43..ed8da428c98 100644
@@ -168,6 +168,9 @@ Supported commands: 'list', 'import'.
 	Can guarantee that when a clone is requested, the received
 	pack is self contained and is connected.
 
+'get'::
+	Can use the 'get' command to download a file from a given URI.
+
 If a helper advertises 'connect', Git will use it if possible and
 fall back to another capability if the helper requests so when
 connecting (see the 'connect' command under COMMANDS).

@@ -418,6 +421,12 @@ Supported if the helper has the "connect" capability.
 +
 Supported if the helper has the "stateless-connect" capability.
 
+'get' <uri> <path>::
+	Downloads the file from the given `<uri>` to the given `<path>`. If
+	`<path>.temp` exists, then Git assumes that the `.temp` file is a
+	partial download from a previous attempt and will resume the
+	download from that position.
+
 If a fatal error occurs, the program writes the error message to
 stderr and exits. The caller should expect that a suitable error
 message has been printed if the child closes the connection without

index b8758757ece..72dfb8fb86a 100644
@@ -1286,6 +1286,29 @@ static void parse_fetch(struct strbuf *buf)
 	strbuf_reset(buf);
 }
 
+static void parse_get(const char *arg)
+{
+	struct strbuf url = STRBUF_INIT;
+	struct strbuf path = STRBUF_INIT;
+	const char *space;
+
+	space = strchr(arg, ' ');
+
+	if (!space)
+		die(_("protocol error: expected '<url> <path>', missing space"));
+
+	strbuf_add(&url, arg, space - arg);
+	strbuf_addstr(&path, space + 1);
+
+	if (http_get_file(url.buf, path.buf, NULL))
+		die(_("failed to download file at URL '%s'"), url.buf);
+
+	strbuf_release(&url);
+	strbuf_release(&path);
+	printf("\n");
+	fflush(stdout);
+}
+
 static int push_dav(int nr_spec, const char **specs)
 {
 	struct child_process child = CHILD_PROCESS_INIT;

@@ -1564,9 +1587,14 @@ int cmd_main(int argc, const char **argv)
 				printf("unsupported\n");
 			fflush(stdout);
 
+		} else if (skip_prefix(buf.buf, "get ", &arg)) {
+			parse_get(arg);
+			fflush(stdout);
+
 		} else if (!strcmp(buf.buf, "capabilities")) {
 			printf("stateless-connect\n");
 			printf("fetch\n");
+			printf("get\n");
 			printf("option\n");
 			printf("push\n");
 			printf("check-connectivity\n");

new file mode 100755
index 00000000000..09fb0bd9a8a
@@ -0,0 +1,37 @@
+#!/bin/sh
+
+test_description='test downloading a file by URL'
+
+. ./test-lib.sh
+
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+test_expect_success 'get by URL: 404' '
+	test_when_finished "rm -f file.temp" &&
+	url="$HTTPD_URL/none.txt" &&
+	cat >input <<-EOF &&
+	capabilities
+	get $url file1
+	EOF
+
+	test_must_fail git remote-http $url <input 2>err &&
+	test_path_is_missing file1 &&
+	grep "failed to download file at URL" err
+'
+
+test_expect_success 'get by URL: 200' '
+	echo data >"$HTTPD_DOCUMENT_ROOT_PATH/exists.txt" &&
+
+	url="$HTTPD_URL/exists.txt" &&
+	cat >input <<-EOF &&
+	capabilities
+	get $url file2
+
+	EOF
+
+	git remote-http $url <input &&
+	test_cmp "$HTTPD_DOCUMENT_ROOT_PATH/exists.txt" file2
+'
+
+test_done

gitgitgadget

From: Derrick Stolee <[email protected]>

Before implementing a way to fetch bundles into a repository, create the basic logic. Assume that the URI is actually a file path. Future logic will make this more careful to other protocols.

For now, we also only succeed if the content at the URI is a bundle file, not a bundle list. Bundle lists will be implemented in a future change.

Note that the discovery of a temporary filename is slightly racy because the odb_mkstemp() relies on the temporary file not existing. With the current implementation being limited to file copies, we could replace the copy_file() with copy_fd(). The tricky part comes in future changes that send the filename to 'git remote-https' and its 'get' capability. At that point, we need the file descriptor closed _and_ the file unlinked. If we were to keep the file descriptor open for the sake of normal file copies, then we would pollute the rest of the code for little benefit. This is especially the case because we expect that most bundle URI use will be based on HTTPS instead of file copies.

---
 Makefile            |   1 +
 bundle-uri.c        | 104 ++++++++++++++++++++++++++++++++++++++++++++
 bundle-uri.h        |  14 ++++++
 t/t5557-http-get.sh |   2 +
 4 files changed, 121 insertions(+)
 create mode 100644 bundle-uri.c
 create mode 100644 bundle-uri.h

index 1624471badc..7d5f48069ea 100644
@@ -906,6 +906,7 @@ LIB_OBJS += blob.o
 LIB_OBJS += bloom.o
 LIB_OBJS += branch.o
 LIB_OBJS += bulk-checkin.o
+LIB_OBJS += bundle-uri.o
 LIB_OBJS += bundle.o
 LIB_OBJS += cache-tree.o
 LIB_OBJS += cbtree.o

new file mode 100644
index 00000000000..8a152f1ef14
@@ -0,0 +1,14 @@
+#ifndef BUNDLE_URI_H
+#define BUNDLE_URI_H
+
+struct repository;
+
+/**
+ * Fetch data from the given 'uri' and unbundle the bundle data found
+ * based on that information.
+ *
+ * Returns non-zero if no bundle information is found at the given 'uri'.
+ */
+int fetch_bundle_uri(struct repository *r, const char *uri);
+
+#endif

index 09fb0bd9a8a..76a4bbd16af 100755
@@ -2,6 +2,8 @@
 
 test_description='test downloading a file by URL'
 
+TEST_PASSES_SANITIZE_LEAK=true
+
 . ./test-lib.sh
 
 . "$TEST_DIRECTORY"/lib-httpd.sh

gitgitgadget

From: Derrick Stolee <[email protected]>

Cloning a remote repository is one of the most expensive operations in Git. The server can spend a lot of CPU time generating a pack-file for the client's request. The amount of data can clog the network for a long time, and the Git protocol is not resumable. For users with poor network connections or are located far away from the origin server, this can be especially painful.

Add a new '--bundle-uri' option to 'git clone' to bootstrap a clone from a bundle. If the user is aware of a bundle server, then they can tell Git to bootstrap the new repository with these bundles before fetching the remaining objects from the origin server.

---
 Documentation/git-clone.txt |  6 ++++++
 builtin/clone.c             | 15 +++++++++++++++
 t/t5558-clone-bundle-uri.sh | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100755 t/t5558-clone-bundle-uri.sh

index 632bd1348ea..60fedf7eb5e 100644
@@ -323,6 +323,12 @@ or `--mirror` is given)
 	for `host.xz:foo/.git`).  Cloning into an existing directory
 	is only allowed if the directory is empty.
 
+--bundle-uri=<uri>::
+	Before fetching from the remote, fetch a bundle from the given
+	`<uri>` and unbundle the data into the local repository. The refs
+	in the bundle will be stored under the hidden `refs/bundle/*`
+	namespace.
+
 :git-clone: 1
 include::urls.txt[]
 

index c4ff4643ecd..4224d562758 100644
@@ -34,6 +34,7 @@
 #include "list-objects-filter-options.h"
 #include "hook.h"
 #include "bundle.h"
+#include "bundle-uri.h"
 
 /*
  * Overall FIXMEs:

@@ -77,6 +78,7 @@ static int option_filter_submodules = -1;    /* unspecified */
 static int config_filter_submodules = -1;    /* unspecified */
 static struct string_list server_options = STRING_LIST_INIT_NODUP;
 static int option_remote_submodules;
+static const char *bundle_uri;
 
 static int recurse_submodules_cb(const struct option *opt,
 				 const char *arg, int unset)

@@ -160,6 +162,8 @@ static struct option builtin_clone_options[] = {
 		    N_("any cloned submodules will use their remote-tracking branch")),
 	OPT_BOOL(0, "sparse", &option_sparse_checkout,
 		    N_("initialize sparse-checkout file to include only files at root")),
+	OPT_STRING(0, "bundle-uri", &bundle_uri,
+		   N_("uri"), N_("a URI for downloading bundles before fetching from origin remote")),
 	OPT_END()
 };
 

@@ -1232,6 +1236,17 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	if (transport->smart_options && !deepen && !filter_options.choice)
 		transport->smart_options->check_self_contained_and_connected = 1;
 
+	/*
+	 * Before fetching from the remote, download and install bundle
+	 * data from the --bundle-uri option.
+	 */
+	if (bundle_uri) {
+		/* At this point, we need the_repository to match the cloned repo. */
+		repo_init(the_repository, git_dir, work_tree);
+		if (fetch_bundle_uri(the_repository, bundle_uri))
+			warning(_("failed to fetch objects from bundle URI '%s'"),
+				bundle_uri);
+	}
 
 	strvec_push(&transport_ls_refs_options.ref_prefixes, "HEAD");
 	refspec_ref_prefixes(&remote->fetch,

new file mode 100755
index 00000000000..f709bcb729c
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+test_description='test fetching bundles with --bundle-uri'
+
+. ./test-lib.sh
+
+test_expect_success 'fail to clone from non-existent file' '
+	test_when_finished rm -rf test &&
+	git clone --bundle-uri="$(pwd)/does-not-exist" . test 2>err &&
+	grep "failed to download bundle from URI" err
+'
+
+test_expect_success 'fail to clone from non-bundle file' '
+	test_when_finished rm -rf test &&
+	echo bogus >bogus &&
+	git clone --bundle-uri="$(pwd)/bogus" . test 2>err &&
+	grep "is not a bundle" err
+'
+
+test_expect_success 'create bundle' '
+	git init clone-from &&
+	git -C clone-from checkout -b topic &&
+	test_commit -C clone-from A &&
+	test_commit -C clone-from B &&
+	git -C clone-from bundle create B.bundle topic
+'
+
+test_expect_success 'clone with path bundle' '
+	git clone --bundle-uri="clone-from/B.bundle" \
+		clone-from clone-path &&
+	git -C clone-path rev-parse refs/bundles/topic >actual &&
+	git -C clone-from rev-parse topic >expect &&
+	test_cmp expect actual
+'
+
+test_done

gitgitgadget

From: Derrick Stolee <[email protected]>

The previous change created the 'git clone --bundle-uri=<uri>' option. Currently, <uri> must be a filename.

Update copy_uri_to_file() to first inspect the URI for an HTTP(S) prefix and use git-remote-https as the way to download the data at that URI. Otherwise, check to see if file:// is present and modify the prefix accordingly.

---
 bundle-uri.c                | 70 +++++++++++++++++++++++++++++++++++--
 t/t5558-clone-bundle-uri.sh | 45 ++++++++++++++++++++++++
 2 files changed, 112 insertions(+), 3 deletions(-)

index b35babc36aa..930e995d194 100644
@@ -23,10 +23,74 @@ static int find_temp_filename(struct strbuf *name)
 	return 0;
 }
 
-static int copy_uri_to_file(const char *file, const char *uri)
+static int download_https_uri_to_file(const char *file, const char *uri)
 {
-	/* File-based URIs only for now. */
-	return copy_file(file, uri, 0);
+	int result = 0;
+	struct child_process cp = CHILD_PROCESS_INIT;
+	FILE *child_in = NULL, *child_out = NULL;
+	struct strbuf line = STRBUF_INIT;
+	int found_get = 0;
+
+	strvec_pushl(&cp.args, "git-remote-https", "origin", uri, NULL);
+	cp.in = -1;
+	cp.out = -1;
+
+	if (start_command(&cp))
+		return 1;
+
+	child_in = fdopen(cp.in, "w");
+	if (!child_in) {
+		result = 1;
+		goto cleanup;
+	}
+
+	child_out = fdopen(cp.out, "r");
+	if (!child_out) {
+		result = 1;
+		goto cleanup;
+	}
+
+	fprintf(child_in, "capabilities\n");
+	fflush(child_in);
+
+	while (!strbuf_getline(&line, child_out)) {
+		if (!line.len)
+			break;
+		if (!strcmp(line.buf, "get"))
+			found_get = 1;
+	}
+	strbuf_release(&line);
+
+	if (!found_get) {
+		result = error(_("insufficient capabilities"));
+		goto cleanup;
+	}
+
+	fprintf(child_in, "get %s %s\n\n", uri, file);
+
+cleanup:
+	if (child_in)
+		fclose(child_in);
+	if (finish_command(&cp))
+		return 1;
+	if (child_out)
+		fclose(child_out);
+	return result;
+}
+
+static int copy_uri_to_file(const char *filename, const char *uri)
+{
+	const char *out;
+
+	if (istarts_with(uri, "https:") ||
+	    istarts_with(uri, "http:"))
+		return download_https_uri_to_file(filename, uri);
+
+	if (!skip_prefix(uri, "file://", &out))
+		out = uri;
+
+	/* Copy as a file */
+	return copy_file(filename, out, 0);
 }
 
 static int unbundle_from_file(struct repository *r, const char *file)

gitgitgadget

Good ideas. Of course, we don't have a skip_iprefix(), but I can use "istarts_with()" and then manually add the length. If we see more need for that in the future, we can consider adding it.

(It's interesting that these uses in bundle-uri.c are the only uses of istarts_with() that I see in the codebase.)

I did a quick check of our HTTPS tests modifying the HTTPD_PROTO variable in lib-httpd.sh to "HtTP" and we get this fun error:

+ git clone --filter=blob:limit=0 HtTP://127.0.0.1:5601/smart/server client Cloning into 'client'...
git: 'remote-HtTP' is not a git command. See 'git --help'.

So I guess I can keep case-sensitive comparisons here.

Thanks,
-Stolee

This part (i.e. check for "<scheme>://", not "<scheme>:") still stands, as the latter could be an scp style Git URL that goes to the host whose name is <scheme>. As mentioned later, s/istarts/starts/ is probably a good thing to do here.

Guarding them to lowercase-only may sound like a cop-out to purists, but I think it is reasonable thing to do. The only folks that would be offended by are protocol lawyers, and as your check shows, we are treating <scheme> case sensitively already.

An obvious alternative is to downcase the "<scheme>://" part but I do not think it is worth it; we have to do that everywhere and we need to be confident that we covered all the code paths---the latter is expensive.

There do exist skip_iprefix() that are used in many places, like convert, http, mailinfo, etc. by the way. That is a moot point as we are not doing case insensitive comparison anymore.

Thanks.

From: Derrick Stolee <[email protected]>

A previous change added the '--bundle-uri' option, but did not check if the --depth parameter was included. Since bundles are not compatible with shallow clones, provide an error message to the user who is attempting this combination.

I am leaving this as its own change, separate from the one that implements '--bundle-uri', because this is more of an advisory for the user. There is nothing wrong with bootstrapping with bundles and then fetching a shallow clone. However, that is likely going to involve too much work for the client _and_ the server. The client will download all of this bundle information containing the full history of the repository only to ignore most of it. The server will get a shallow fetch request, but with a list of haves that might cause a more painful computation of that shallow pack-file.

---
 Documentation/git-clone.txt | 3 ++-
 builtin/clone.c             | 3 +++
 t/t5606-clone-options.sh    | 8 ++++++++
 3 files changed, 13 insertions(+), 1 deletion(-)

index 60fedf7eb5e..d032d971dd7 100644
@@ -327,7 +327,8 @@ or `--mirror` is given)
 	Before fetching from the remote, fetch a bundle from the given
 	`<uri>` and unbundle the data into the local repository. The refs
 	in the bundle will be stored under the hidden `refs/bundle/*`
-	namespace.
+	namespace. This option is incompatible with `--depth`,
+	`--shallow-since`, and `--shallow-exclude`.
 
 :git-clone: 1
 include::urls.txt[]

index 4224d562758..4463789680b 100644
@@ -937,6 +937,9 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		option_no_checkout = 1;
 	}
 
+	if (bundle_uri && deepen)
+		die(_("--bundle-uri is incompatible with --depth, --shallow-since, and --shallow-exclude"));
+
 	repo_name = argv[0];
 
 	path = get_repo_path(repo_name, &is_bundle);

index 8f676d6b0c0..f6bb02ab947 100755
@@ -58,6 +58,14 @@ test_expect_success 'disallows --bare with --separate-git-dir' '
 
 '
 
+test_expect_success 'disallows --bundle-uri with shallow options' '
+	for option in --depth=1 --shallow-since=01-01-2000 --shallow-exclude=HEAD
+	do
+		test_must_fail git clone --bundle-uri=bundle $option from to 2>err &&
+		grep "bundle-uri is incompatible" err || return 1
+	done
+'
+
 test_expect_success 'reject cloning shallow repository' '
 	test_when_finished "rm -rf repo" &&
 	test_must_fail git clone --reject-shallow shallow-repo out 2>err &&

gitgitgadget

This is the second series building the bundle URI feature as discussed in the previous series that added the design document [1]. This series does not modify the design document, so the patches are independent and can be applied to the latest 'master'.

[1]
https://lore.kernel.org/git/[email protected]

This series brings in just enough logic that we can bootstrap clones from a single bundle using git clone --bundle-uri=<X>.

* Patch 1 adds a 'get' capability to 'git remote-https' which allows downloading the contents of a URI to a local file.
* Patch 2 creates basic file-copy logic within a new bundle-uri.c file. It is not used until patch 3.
* Patch 3 creates the git clone --bundle-uri=<X> option, allowing Git to bootstrap a clone from a bundle, but get the remaining objects from the origin URL. (As of this patch, it only accepts a filename.)
* Patch 4 extends the git clone --bundle-uri=<X> option to allow file:// and https:// URIs.
* Patch 5 is a CLI helper to avoid using --bundle-uri and --depth at the same time in git clone.

As outlined in [1], the next steps after this are:

1. Allow parsing a bundle list as a config file at the given URI. The key-value format is unified with the protocol v2 verb (coming in (3)).
[2]
2. Implement the protocol v2 verb, re-using the bundle list logic from (2). Use this to auto-discover bundle URIs during 'git clone' (behind a config option). [3]
3. Implement the 'creationToken' heuristic, allowing incremental 'git fetch' commands to download a bundle list from a configured URI, and only download bundles that are new based on the creation token values.
[4]

I have prepared some of this work as pull requests on my personal fork so curious readers can look ahead to where we are going:

[2] https://github.com/derrickstolee/git/pull/20

[3] https://github.com/derrickstolee/git/pull/21

[4] https://github.com/derrickstolee/git/pull/22

Note: this series includes some code pulled out of the first series [1], and in particular the git fetch --bundle-uri=<X> option is removed. The intention was to replace that with git bundle fetch <X>, but that conflicts with the work to refactor how subcommands are parsed. The git bundle fetch subcommand could be added later for maximum flexibility on the client side, but we can also move forward without it.

Updates in v3
=============

* The protocol matching for "http://", "https://", and "file://" now uniformly include the "//" portion and are case-sensitive.

Updates in v2
=============

* Several typos or small tweaks. See the range-diff for details.

Thanks, -Stolee

Derrick Stolee (5):
remote-curl: add 'get' capability
bundle-uri: create basic file-copy logic
clone: add --bundle-uri option
bundle-uri: add support for http(s):// and file://
clone: --bundle-uri cannot be combined with --depth

 Documentation/git-clone.txt         |   7 ++
 Documentation/gitremote-helpers.txt |   9 ++
 Makefile                            |   1 +
 builtin/clone.c                     |  18 +++
 bundle-uri.c                        | 168 ++++++++++++++++++++++++++++
 bundle-uri.h                        |  14 +++
 remote-curl.c                       |  28 +++++
 t/t5557-http-get.sh                 |  39 +++++++
 t/t5558-clone-bundle-uri.sh         |  81 ++++++++++++++
 t/t5606-clone-options.sh            |   8 ++
 10 files changed, 373 insertions(+)
 create mode 100644 bundle-uri.c
 create mode 100644 bundle-uri.h
 create mode 100755 t/t5557-http-get.sh
 create mode 100755 t/t5558-clone-bundle-uri.sh

base-commit: e72d93e88cb20b06e88e6e7d81bd1dc4effe453f
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1300%2Fderrickstolee%2Fbundle-redo%2Fclone-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1300/derrickstolee/bundle-redo/clone-v3
Pull-Request: https://github.com/gitgitgadget/git/pull/1300

Range-diff vs v2:

 1:  4df4a1d679a = 1:  4df4a1d679a remote-curl: add 'get' capability
 2:  6a6f1a04889 = 2:  6a6f1a04889 bundle-uri: create basic file-copy logic
 3:  00debaf6e77 = 3:  00debaf6e77 clone: add --bundle-uri option
 4:  e4f2dcc7a45 ! 4:  66a1ce40451 bundle-uri: add support for http(s):// and file://
     @@ bundle-uri.c: static int find_temp_filename(struct strbuf *name)
      +	struct strbuf line = STRBUF_INIT;
      +	int found_get = 0;
      +
     -+	strvec_pushl(&cp.args, "git-remote-https", "origin", uri, NULL);
     ++	strvec_pushl(&cp.args, "git-remote-https", uri, NULL);
      +	cp.in = -1;
      +	cp.out = -1;
      +
     @@ bundle-uri.c: static int find_temp_filename(struct strbuf *name)
      +{
      +	const char *out;
      +
     -+	if (istarts_with(uri, "https:") ||
     -+	    istarts_with(uri, "http:"))
     ++	if (starts_with(uri, "https:") ||
     ++	    starts_with(uri, "http:"))
      +		return download_https_uri_to_file(filename, uri);
      +
     -+	if (!skip_prefix(uri, "file://", &out))
     -+		out = uri;
     ++	if (skip_prefix(uri, "file://", &out))
     ++		uri = out;
      +
      +	/* Copy as a file */
     -+	return copy_file(filename, out, 0);
     ++	return copy_file(filename, uri, 0);
       }
       
       static int unbundle_from_file(struct repository *r, const char *file)

5: acee1fae027 = 5: ed76d84c5a7 clone: --bundle-uri cannot be combined with --depth

gitgitgadget

From: Derrick Stolee <[email protected]>

A future change will want a way to download a file over HTTP(S) using the simplest of download mechanisms. We do not want to assume that the server on the other side understands anything about the Git protocol but could be a simple static web server.

Create the new 'get' capability for the remote helpers which advertises that the 'get' command is avalable. A caller can send a line containing 'get <url> <path>' to download the file at <url> into the file at <path>.

---
 Documentation/gitremote-helpers.txt |  9 +++++++
 remote-curl.c                       | 28 ++++++++++++++++++++++
 t/t5557-http-get.sh                 | 37 +++++++++++++++++++++++++++++
 3 files changed, 74 insertions(+)
 create mode 100755 t/t5557-http-get.sh

index 6f1e269ae43..ed8da428c98 100644
@@ -168,6 +168,9 @@ Supported commands: 'list', 'import'.
 	Can guarantee that when a clone is requested, the received
 	pack is self contained and is connected.
 
+'get'::
+	Can use the 'get' command to download a file from a given URI.
+
 If a helper advertises 'connect', Git will use it if possible and
 fall back to another capability if the helper requests so when
 connecting (see the 'connect' command under COMMANDS).

@@ -418,6 +421,12 @@ Supported if the helper has the "connect" capability.
 +
 Supported if the helper has the "stateless-connect" capability.
 
+'get' <uri> <path>::
+	Downloads the file from the given `<uri>` to the given `<path>`. If
+	`<path>.temp` exists, then Git assumes that the `.temp` file is a
+	partial download from a previous attempt and will resume the
+	download from that position.
+
 If a fatal error occurs, the program writes the error message to
 stderr and exits. The caller should expect that a suitable error
 message has been printed if the child closes the connection without

index b8758757ece..72dfb8fb86a 100644
@@ -1286,6 +1286,29 @@ static void parse_fetch(struct strbuf *buf)
 	strbuf_reset(buf);
 }
 
+static void parse_get(const char *arg)
+{
+	struct strbuf url = STRBUF_INIT;
+	struct strbuf path = STRBUF_INIT;
+	const char *space;
+
+	space = strchr(arg, ' ');
+
+	if (!space)
+		die(_("protocol error: expected '<url> <path>', missing space"));
+
+	strbuf_add(&url, arg, space - arg);
+	strbuf_addstr(&path, space + 1);
+
+	if (http_get_file(url.buf, path.buf, NULL))
+		die(_("failed to download file at URL '%s'"), url.buf);
+
+	strbuf_release(&url);
+	strbuf_release(&path);
+	printf("\n");
+	fflush(stdout);
+}
+
 static int push_dav(int nr_spec, const char **specs)
 {
 	struct child_process child = CHILD_PROCESS_INIT;

@@ -1564,9 +1587,14 @@ int cmd_main(int argc, const char **argv)
 				printf("unsupported\n");
 			fflush(stdout);
 
+		} else if (skip_prefix(buf.buf, "get ", &arg)) {
+			parse_get(arg);
+			fflush(stdout);
+
 		} else if (!strcmp(buf.buf, "capabilities")) {
 			printf("stateless-connect\n");
 			printf("fetch\n");
+			printf("get\n");
 			printf("option\n");
 			printf("push\n");
 			printf("check-connectivity\n");

new file mode 100755
index 00000000000..09fb0bd9a8a
@@ -0,0 +1,37 @@
+#!/bin/sh
+
+test_description='test downloading a file by URL'
+
+. ./test-lib.sh
+
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+test_expect_success 'get by URL: 404' '
+	test_when_finished "rm -f file.temp" &&
+	url="$HTTPD_URL/none.txt" &&
+	cat >input <<-EOF &&
+	capabilities
+	get $url file1
+	EOF
+
+	test_must_fail git remote-http $url <input 2>err &&
+	test_path_is_missing file1 &&
+	grep "failed to download file at URL" err
+'
+
+test_expect_success 'get by URL: 200' '
+	echo data >"$HTTPD_DOCUMENT_ROOT_PATH/exists.txt" &&
+
+	url="$HTTPD_URL/exists.txt" &&
+	cat >input <<-EOF &&
+	capabilities
+	get $url file2
+
+	EOF
+
+	git remote-http $url <input &&
+	test_cmp "$HTTPD_DOCUMENT_ROOT_PATH/exists.txt" file2
+'
+
+test_done

gitgitgadget

From: Derrick Stolee <[email protected]>

Before implementing a way to fetch bundles into a repository, create the basic logic. Assume that the URI is actually a file path. Future logic will make this more careful to other protocols.

For now, we also only succeed if the content at the URI is a bundle file, not a bundle list. Bundle lists will be implemented in a future change.

Note that the discovery of a temporary filename is slightly racy because the odb_mkstemp() relies on the temporary file not existing. With the current implementation being limited to file copies, we could replace the copy_file() with copy_fd(). The tricky part comes in future changes that send the filename to 'git remote-https' and its 'get' capability. At that point, we need the file descriptor closed _and_ the file unlinked. If we were to keep the file descriptor open for the sake of normal file copies, then we would pollute the rest of the code for little benefit. This is especially the case because we expect that most bundle URI use will be based on HTTPS instead of file copies.

---
 Makefile            |   1 +
 bundle-uri.c        | 104 ++++++++++++++++++++++++++++++++++++++++++++
 bundle-uri.h        |  14 ++++++
 t/t5557-http-get.sh |   2 +
 4 files changed, 121 insertions(+)
 create mode 100644 bundle-uri.c
 create mode 100644 bundle-uri.h

index 1624471badc..7d5f48069ea 100644
@@ -906,6 +906,7 @@ LIB_OBJS += blob.o
 LIB_OBJS += bloom.o
 LIB_OBJS += branch.o
 LIB_OBJS += bulk-checkin.o
+LIB_OBJS += bundle-uri.o
 LIB_OBJS += bundle.o
 LIB_OBJS += cache-tree.o
 LIB_OBJS += cbtree.o

new file mode 100644
index 00000000000..8a152f1ef14
@@ -0,0 +1,14 @@
+#ifndef BUNDLE_URI_H
+#define BUNDLE_URI_H
+
+struct repository;
+
+/**
+ * Fetch data from the given 'uri' and unbundle the bundle data found
+ * based on that information.
+ *
+ * Returns non-zero if no bundle information is found at the given 'uri'.
+ */
+int fetch_bundle_uri(struct repository *r, const char *uri);
+
+#endif

index 09fb0bd9a8a..76a4bbd16af 100755
@@ -2,6 +2,8 @@
 
 test_description='test downloading a file by URL'
 
+TEST_PASSES_SANITIZE_LEAK=true
+
 . ./test-lib.sh
 
 . "$TEST_DIRECTORY"/lib-httpd.sh

gitgitgadget

From: Derrick Stolee <[email protected]>

Cloning a remote repository is one of the most expensive operations in Git. The server can spend a lot of CPU time generating a pack-file for the client's request. The amount of data can clog the network for a long time, and the Git protocol is not resumable. For users with poor network connections or are located far away from the origin server, this can be especially painful.

Add a new '--bundle-uri' option to 'git clone' to bootstrap a clone from a bundle. If the user is aware of a bundle server, then they can tell Git to bootstrap the new repository with these bundles before fetching the remaining objects from the origin server.

---
 Documentation/git-clone.txt |  6 ++++++
 builtin/clone.c             | 15 +++++++++++++++
 t/t5558-clone-bundle-uri.sh | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100755 t/t5558-clone-bundle-uri.sh

index 632bd1348ea..60fedf7eb5e 100644
@@ -323,6 +323,12 @@ or `--mirror` is given)
 	for `host.xz:foo/.git`).  Cloning into an existing directory
 	is only allowed if the directory is empty.
 
+--bundle-uri=<uri>::
+	Before fetching from the remote, fetch a bundle from the given
+	`<uri>` and unbundle the data into the local repository. The refs
+	in the bundle will be stored under the hidden `refs/bundle/*`
+	namespace.
+
 :git-clone: 1
 include::urls.txt[]
 

index c4ff4643ecd..4224d562758 100644
@@ -34,6 +34,7 @@
 #include "list-objects-filter-options.h"
 #include "hook.h"
 #include "bundle.h"
+#include "bundle-uri.h"
 
 /*
  * Overall FIXMEs:

@@ -77,6 +78,7 @@ static int option_filter_submodules = -1;    /* unspecified */
 static int config_filter_submodules = -1;    /* unspecified */
 static struct string_list server_options = STRING_LIST_INIT_NODUP;
 static int option_remote_submodules;
+static const char *bundle_uri;
 
 static int recurse_submodules_cb(const struct option *opt,
 				 const char *arg, int unset)

@@ -160,6 +162,8 @@ static struct option builtin_clone_options[] = {
 		    N_("any cloned submodules will use their remote-tracking branch")),
 	OPT_BOOL(0, "sparse", &option_sparse_checkout,
 		    N_("initialize sparse-checkout file to include only files at root")),
+	OPT_STRING(0, "bundle-uri", &bundle_uri,
+		   N_("uri"), N_("a URI for downloading bundles before fetching from origin remote")),
 	OPT_END()
 };
 

@@ -1232,6 +1236,17 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	if (transport->smart_options && !deepen && !filter_options.choice)
 		transport->smart_options->check_self_contained_and_connected = 1;
 
+	/*
+	 * Before fetching from the remote, download and install bundle
+	 * data from the --bundle-uri option.
+	 */
+	if (bundle_uri) {
+		/* At this point, we need the_repository to match the cloned repo. */
+		repo_init(the_repository, git_dir, work_tree);
+		if (fetch_bundle_uri(the_repository, bundle_uri))
+			warning(_("failed to fetch objects from bundle URI '%s'"),
+				bundle_uri);
+	}
 
 	strvec_push(&transport_ls_refs_options.ref_prefixes, "HEAD");
 	refspec_ref_prefixes(&remote->fetch,

new file mode 100755
index 00000000000..f709bcb729c
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+test_description='test fetching bundles with --bundle-uri'
+
+. ./test-lib.sh
+
+test_expect_success 'fail to clone from non-existent file' '
+	test_when_finished rm -rf test &&
+	git clone --bundle-uri="$(pwd)/does-not-exist" . test 2>err &&
+	grep "failed to download bundle from URI" err
+'
+
+test_expect_success 'fail to clone from non-bundle file' '
+	test_when_finished rm -rf test &&
+	echo bogus >bogus &&
+	git clone --bundle-uri="$(pwd)/bogus" . test 2>err &&
+	grep "is not a bundle" err
+'
+
+test_expect_success 'create bundle' '
+	git init clone-from &&
+	git -C clone-from checkout -b topic &&
+	test_commit -C clone-from A &&
+	test_commit -C clone-from B &&
+	git -C clone-from bundle create B.bundle topic
+'
+
+test_expect_success 'clone with path bundle' '
+	git clone --bundle-uri="clone-from/B.bundle" \
+		clone-from clone-path &&
+	git -C clone-path rev-parse refs/bundles/topic >actual &&
+	git -C clone-from rev-parse topic >expect &&
+	test_cmp expect actual
+'
+
+test_done

gitgitgadget

Thank you for pointing this out. Here is a patch that fixes the issue from this patch:

--- >8 ---

From 6df8bc6d7ffdc1b115d85ef9550bab5dcf1811f8 Mon Sep 17 00:00:00 2001
From: Derrick Stolee <[email protected]>
Date: Tue, 23 Aug 2022 09:53:47 -0400
Subject: [PATCH] clone: warn on failure to repo_init()

The --bundle-uri option was added in 55568919616 (clone: add --bundle-uri option, 2022-08-09), but this also introduced a call to repo_init() whose return value was ignored. Fix that ignored value by warning that the bundle URI process could not continue if it failed.

---
 builtin/clone.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

index 4463789680b..e21d42dfee5 100644
@@ -1245,8 +1245,9 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	 */
 	if (bundle_uri) {
 		/* At this point, we need the_repository to match the cloned repo. */
-		repo_init(the_repository, git_dir, work_tree);
-		if (fetch_bundle_uri(the_repository, bundle_uri))
+		if (repo_init(the_repository, git_dir, work_tree))
+			warning(_("failed to initialize the repo, skipping bundle URI"));
+		else if (fetch_bundle_uri(the_repository, bundle_uri))
 			warning(_("failed to fetch objects from bundle URI '%s'"),
 				bundle_uri);
 	}

2.37.1.vfs.0.0.rebase

OK. It looks like a sensible thing to do.

From: Derrick Stolee <[email protected]>

The previous change created the 'git clone --bundle-uri=<uri>' option. Currently, <uri> must be a filename.

Update copy_uri_to_file() to first inspect the URI for an HTTP(S) prefix and use git-remote-https as the way to download the data at that URI. Otherwise, check to see if file:// is present and modify the prefix accordingly.

---
 bundle-uri.c                | 70 +++++++++++++++++++++++++++++++++++--
 t/t5558-clone-bundle-uri.sh | 45 ++++++++++++++++++++++++
 2 files changed, 112 insertions(+), 3 deletions(-)

index b35babc36aa..4a8cc74ed05 100644
@@ -23,10 +23,74 @@ static int find_temp_filename(struct strbuf *name)
 	return 0;
 }
 
-static int copy_uri_to_file(const char *file, const char *uri)
+static int download_https_uri_to_file(const char *file, const char *uri)
 {
-	/* File-based URIs only for now. */
-	return copy_file(file, uri, 0);
+	int result = 0;
+	struct child_process cp = CHILD_PROCESS_INIT;
+	FILE *child_in = NULL, *child_out = NULL;
+	struct strbuf line = STRBUF_INIT;
+	int found_get = 0;
+
+	strvec_pushl(&cp.args, "git-remote-https", uri, NULL);
+	cp.in = -1;
+	cp.out = -1;
+
+	if (start_command(&cp))
+		return 1;
+
+	child_in = fdopen(cp.in, "w");
+	if (!child_in) {
+		result = 1;
+		goto cleanup;
+	}
+
+	child_out = fdopen(cp.out, "r");
+	if (!child_out) {
+		result = 1;
+		goto cleanup;
+	}
+
+	fprintf(child_in, "capabilities\n");
+	fflush(child_in);
+
+	while (!strbuf_getline(&line, child_out)) {
+		if (!line.len)
+			break;
+		if (!strcmp(line.buf, "get"))
+			found_get = 1;
+	}
+	strbuf_release(&line);
+
+	if (!found_get) {
+		result = error(_("insufficient capabilities"));
+		goto cleanup;
+	}
+
+	fprintf(child_in, "get %s %s\n\n", uri, file);
+
+cleanup:
+	if (child_in)
+		fclose(child_in);
+	if (finish_command(&cp))
+		return 1;
+	if (child_out)
+		fclose(child_out);
+	return result;
+}
+
+static int copy_uri_to_file(const char *filename, const char *uri)
+{
+	const char *out;
+
+	if (starts_with(uri, "https:") ||
+	    starts_with(uri, "http:"))
+		return download_https_uri_to_file(filename, uri);
+
+	if (skip_prefix(uri, "file://", &out))
+		uri = out;
+
+	/* Copy as a file */
+	return copy_file(filename, uri, 0);
 }
 
 static int unbundle_from_file(struct repository *r, const char *file)

gitgitgadget

Teng, you are right that it does not hurt to have a 'break' here. Since this topic has already merged, that change will need a forward-fix that I can add to a future series.

Thanks,
-Stolee

From: Derrick Stolee <[email protected]>

A previous change added the '--bundle-uri' option, but did not check if the --depth parameter was included. Since bundles are not compatible with shallow clones, provide an error message to the user who is attempting this combination.

I am leaving this as its own change, separate from the one that implements '--bundle-uri', because this is more of an advisory for the user. There is nothing wrong with bootstrapping with bundles and then fetching a shallow clone. However, that is likely going to involve too much work for the client _and_ the server. The client will download all of this bundle information containing the full history of the repository only to ignore most of it. The server will get a shallow fetch request, but with a list of haves that might cause a more painful computation of that shallow pack-file.

---
 Documentation/git-clone.txt | 3 ++-
 builtin/clone.c             | 3 +++
 t/t5606-clone-options.sh    | 8 ++++++++
 3 files changed, 13 insertions(+), 1 deletion(-)

index 60fedf7eb5e..d032d971dd7 100644
@@ -327,7 +327,8 @@ or `--mirror` is given)
 	Before fetching from the remote, fetch a bundle from the given
 	`<uri>` and unbundle the data into the local repository. The refs
 	in the bundle will be stored under the hidden `refs/bundle/*`
-	namespace.
+	namespace. This option is incompatible with `--depth`,
+	`--shallow-since`, and `--shallow-exclude`.
 
 :git-clone: 1
 include::urls.txt[]

index 4224d562758..4463789680b 100644
@@ -937,6 +937,9 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		option_no_checkout = 1;
 	}
 
+	if (bundle_uri && deepen)
+		die(_("--bundle-uri is incompatible with --depth, --shallow-since, and --shallow-exclude"));
+
 	repo_name = argv[0];
 
 	path = get_repo_path(repo_name, &is_bundle);

index 8f676d6b0c0..f6bb02ab947 100755
@@ -58,6 +58,14 @@ test_expect_success 'disallows --bare with --separate-git-dir' '
 
 '
 
+test_expect_success 'disallows --bundle-uri with shallow options' '
+	for option in --depth=1 --shallow-since=01-01-2000 --shallow-exclude=HEAD
+	do
+		test_must_fail git clone --bundle-uri=bundle $option from to 2>err &&
+		grep "bundle-uri is incompatible" err || return 1
+	done
+'
+
 test_expect_success 'reject cloning shallow repository' '
 	test_when_finished "rm -rf repo" &&
 	test_must_fail git clone --reject-shallow shallow-repo out 2>err &&

gitgitgadget