commit-graph: add verify changed paths option

From: Son Luong Ngoc <[email protected]>

Add '--has-changed-paths' option to 'git commit-graph verify' subcommand to validate whether the commit-graph was written with '--changed-paths' option.

Signed-off-by Son Luong Ngoc <[email protected]>

It's probably going to take me a bit more time to write up some tests for this,

so I want to send it out first for comments.

builtin/commit-graph.c +6 -2

index 16c9f6101a..ce8a7cbe90 100644
@@ -18,7 +18,8 @@ static char const * const builtin_commit_graph_usage[] = {
 };
 
 static const char * const builtin_commit_graph_verify_usage[] = {
-       N_("git commit-graph verify [--object-dir <objdir>] [--shallow] [--[no-]progress]"),
+       N_("git commit-graph verify [--object-dir <objdir>] [--shallow] "
+           "[--has-changed-paths] [--[no-]progress]"),
        NULL
 };
 

@@ -37,6 +38,7 @@ static struct opts_commit_graph {
        int append;
        int split;
        int shallow;
+       int has_changed_paths;
        int progress;
        int enable_changed_paths;
 } opts;

@@ -71,12 +73,14 @@ static int graph_verify(int argc, const char **argv)
        int open_ok;
        int fd;
        struct stat st;
-       int flags = 0;
+       enum commit_graph_verify_flags flags = 0;
 
        static struct option builtin_commit_graph_verify_options[] = {
                OPT_STRING(0, "object-dir", &opts.obj_dir,
                           N_("dir"),
                           N_("The object directory to store the graph")),
+               OPT_BOOL(0, "has-changed-paths", &opts.has_changed_paths,
+                        N_("verify that the commit-graph includes changed paths")),
                OPT_BOOL(0, "shallow", &opts.shallow,
                         N_("if the commit-graph is split, only verify the tip file")),
                OPT_BOOL(0, "progress", &opts.progress, N_("force progress reporting")),

builtin/commit-graph.c +0 -0

        odb = find_odb(the_repository, opts.obj_dir);
        graph_name = get_commit_graph_filename(odb);

commit-graph.c +1 -1

index 1af68c297d..d83f5a2325 100644
@@ -250,7 +250,7 @@ struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st,
        return ret;
 }
 
-static int verify_commit_graph_lite(struct commit_graph *g)
+static int verify_commit_graph_lite(struct commit_graph *g, int verify_changed_path)

From: Son Luong Ngoc <[email protected]>

Add '--has-changed-paths' option to 'git commit-graph verify' subcommand to validate whether the commit-graph was written with '--changed-paths' option.

Quoted 5 lines · Son Luong Ngoc via GitGitGadget

From: Son Luong Ngoc <[email protected]>

Add '--has-changed-paths' option to 'git commit-graph verify' subcommand to validate whether the commit-graph was written with '--changed-paths' option.

The implementation seems to be only about "does this section exist?" and not "does this section have healthy/uncorrupted data?", which feels a bit strange for "verify". Instead of setting ourselves up to having to add "--has-this-section" and "--has-that-section" every time a new kind of data is added to the system, how about giving the verify command an option to list all the sections found in the file, or a separate "git commit-graph list-sections" subcommand?

From: Son Luong Ngoc <[email protected]>

Add '--has-changed-paths' option to 'git commit-graph verify' subcommand to validate whether the commit-graph was written with '--changed-paths' option.

Quoted 5 lines · Son Luong Ngoc via GitGitGadget

From: Son Luong Ngoc <[email protected]>

Add '--has-changed-paths' option to 'git commit-graph verify' subcommand to validate whether the commit-graph was written with '--changed-paths' option.

Is a single boolean flag sufficient? If you have incrementals, you might have some slices with this chunk and some without. What should the boolean be in that case?

I thought we had some way of reporting the number of commits covered by filters, but I can't seem to find it.

Our "test-tool read-graph" can report on whether there's a bloom filter chunk, but I think it also doesn't distinguish between different slices (and anyway, it wouldn't be suitable for tools that don't rely on an actual built git.git directory).

-Peff

Quoted 3 lines

Is a single boolean flag sufficient? If you have incrementals, you might have some slices with this chunk and some without. What should the boolean be in that case?

I think you'd really want to know which layers do and don't have filters. It might be even more interesting to have a tool like what 'git show-index' is to '*.idx' files, maybe something like 'git show-graph' or 'git show-commit-graph'. Its output would be one line per commit that shows:

- what layer in the chain it's located at
- its graph_pos
- its generation number
- whether or not it has a Bloom filter
- ???

That would be a useful tool for debugging anyway, even outside of the test suite. It would be even better if we could replace the test-tool with it.

Quoted 16 lines · Taylor Blau

Quoted 3 lines

Is a single boolean flag sufficient? If you have incrementals, you might have some slices with this chunk and some without. What should the boolean be in that case?

I think you'd really want to know which layers do and don't have filters. It might be even more interesting to have a tool like what 'git show-index' is to '*.idx' files, maybe something like 'git show-graph' or 'git show-commit-graph'. Its output would be one line per commit that shows:

- what layer in the chain it's located at
- its graph_pos
- its generation number
- whether or not it has a Bloom filter
- ???

Quoted 3 lines

That would be a useful tool for debugging anyway, even outside of the test suite. It would be even better if we could replace the test-tool with it.

Yeah, that was exactly what I had in mind, except that I'd make it a sub-command of "git commit-graph" ("show" or perhaps "dump").

-Peff