rebase: display an error if --root and --fork-point are both provided

From: Elijah Newren <[email protected]>

--root implies we want to rebase all commits since the beginning of history. --fork-point means we want to use the reflog of the specified upstream to find the best common ancestor between <upstream> and <branch> and only rebase commits since that common ancestor. These options are clearly contradictory, so throw an error (instead of segfaulting on a NULL pointer) if both are specified.

---
rebase: display an error if --root and --fork-point are both provided

--root implies we want to rebase all commits since the beginning of history. --fork-point means we want to use the reflog of the specified upstream to find the best common ancestor between and and only rebase commits since that common ancestor. These options are clearly contradictory, so throw an error (instead of segfaulting on a NULL pointer) if both are specified.

[[email protected]]Signed-off-by: Elijah Newren [email protected] [[email protected]]

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-771%2Fnewren%2Frebase-fork-point-root-error-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-771/newren/rebase-fork-point-root-error-v1
Pull-Request: https://github.com/git/git/pull/771

 builtin/rebase.c | 3 +++
 1 file changed, 3 insertions(+)

index bff53d5d167..287ac1aa21b 100644
@@ -1652,6 +1652,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			die(_("cannot combine '--keep-base' with '--root'"));
 	}
 
+	if (options.root && fork_point > 0)
+		die(_("cannot combine '--root' with '--fork-point'"));
+
 	if (action != ACTION_NONE && !in_progress)
 		die(_("No rebase in progress?"));
 	setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);

base-commit: af6b65d45ef179ed52087e80cb089f6b2349f4ec

gitgitgadget

Hi Elijah,

Le 27/04/2020 à 18:21, Elijah Newren via GitGitGadget a écrit :

The patch is fairly obvious and looks good to me.

The documentation must be updated, too, since it does not mention the incompatibility between the two switches:

-- snip --

index bed500f151..a30de5aa20 100644
@@ -448,12 +448,14 @@ When --fork-point is active, 'fork_point' will be

used instead of
<branch>` command (see linkgit:git-merge-base[1]). If 'fork_point' ends up being empty, the <upstream> will be used as a fallback. +
-If either <upstream> or --root is given on the command line, then the -default is --no-fork-point, otherwise the default is --fork-point. +If <upstream> is given on the command line, then the default is +--no-fork-point, otherwise the default is --fork-point.
+
If your branch was based on <upstream> but <upstream> was rewound and your branch contains commits which were dropped, this option can be used with --keep-base in order to drop those commits from your branch.
++
+See also INCOMPATIBLE OPTIONS below.

--ignore-whitespace::
--whitespace=<option>::
@@ -635,6 +637,7 @@ In addition, the following pairs of options are incompatible:
* --preserve-merges and --empty=
* --keep-base and --onto
* --keep-base and --root
+ * --fork-point and --root

BEHAVIORAL DIFFERENCES
-----------------------
-- snap --

Cheers,
Alban

From: Elijah Newren <[email protected]>

--root implies we want to rebase all commits since the beginning of history. --fork-point means we want to use the reflog of the specified upstream to find the best common ancestor between <upstream> and <branch> and only rebase commits since that common ancestor. These options are clearly contradictory, so throw an error (instead of segfaulting on a NULL pointer) if both are specified.

---
rebase: display an error if --root and --fork-point are both provided

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-771%2Fnewren%2Frebase-fork-point-root-error-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-771/newren/rebase-fork-point-root-error-v2
Pull-Request: https://github.com/git/git/pull/771

Range-diff vs v1:

1: c4508c7ddae ! 1: 307124b00d4 rebase: display an error if --root and --fork-point are both provided
@@ Commit message
segfaulting on a NULL pointer) if both are specified.

+ Documentation-by: Alban Gruin <[email protected]>

+ ## Documentation/git-rebase.txt ##
+@@ Documentation/git-rebase.txt: When --fork-point is active, 'fork_point' will be used instead of
+ <branch>` command (see linkgit:git-merge-base[1]). If 'fork_point'
+ ends up being empty, the <upstream> will be used as a fallback.
+ +
+-If either <upstream> or --root is given on the command line, then the
+-default is --no-fork-point, otherwise the default is --fork-point.
++If <upstream> is given on the command line, then the default is ++--no-fork-point, otherwise the default is --fork-point.
+ +
+ If your branch was based on <upstream> but <upstream> was rewound and
+ your branch contains commits which were dropped, this option can be used
+ with --keep-base in order to drop those commits from your branch.
+++
++See also INCOMPATIBLE OPTIONS below.
+
+ --ignore-whitespace::
+ --whitespace=<option>::
+@@ Documentation/git-rebase.txt: In addition, the following pairs of options are incompatible:
+ * --preserve-merges and --empty=
+ * --keep-base and --onto
+ * --keep-base and --root
++ * --fork-point and --root
+
+ BEHAVIORAL DIFFERENCES
+ -----------------------
+
## builtin/rebase.c ##
@@ builtin/rebase.c: int cmd_rebase(int argc, const char **argv, const char *prefix)
die(_("cannot combine '--keep-base' with '--root'"));

 Documentation/git-rebase.txt | 7 +++++--
 builtin/rebase.c             | 3 +++
 2 files changed, 8 insertions(+), 2 deletions(-)

index f7a6033607f..fbad356c68e 100644
@@ -414,12 +414,14 @@ When --fork-point is active, 'fork_point' will be used instead of
 <branch>` command (see linkgit:git-merge-base[1]).  If 'fork_point'
 ends up being empty, the <upstream> will be used as a fallback.
 +
-If either <upstream> or --root is given on the command line, then the
-default is `--no-fork-point`, otherwise the default is `--fork-point`.
+If <upstream> is given on the command line, then the default is
+`--no-fork-point`, otherwise the default is `--fork-point`.
 +
 If your branch was based on <upstream> but <upstream> was rewound and
 your branch contains commits which were dropped, this option can be used
 with `--keep-base` in order to drop those commits from your branch.
++
+See also INCOMPATIBLE OPTIONS below.
 
 --ignore-whitespace::
 --whitespace=<option>::

@@ -600,6 +602,7 @@ In addition, the following pairs of options are incompatible:
  * --preserve-merges and --empty=
  * --keep-base and --onto
  * --keep-base and --root
+ * --fork-point and --root
 
 BEHAVIORAL DIFFERENCES
 -----------------------

index bff53d5d167..287ac1aa21b 100644
@@ -1652,6 +1652,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			die(_("cannot combine '--keep-base' with '--root'"));
 	}
 
+	if (options.root && fork_point > 0)
+		die(_("cannot combine '--root' with '--fork-point'"));
+
 	if (action != ACTION_NONE && !in_progress)
 		die(_("No rebase in progress?"));
 	setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);

base-commit: af6b65d45ef179ed52087e80cb089f6b2349f4ec

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