[PATCH] builtin-commit: use reduce_heads() only when appropriate
- From
SZEDER Gábor <szeder@ira.uka.de>
- Date
- Oct 3, 2008, 15:09 UTC
- Message-ID
- <20081003150927.GG6839@neumann>
- In-Reply-To
- <1223035487-2576-1-git-send-email-vmiklos@frugalware.org>
Since commit 6bb6b034 (builtin-commit: use commit_tree(), 2008-09-10), builtin-commit performs a reduce_heads() unconditionally. However, it's not always needed, and in some cases even harmful.
reduce_heads() is not needed for the initial commit or for an "ordinary" commit, because they don't have any or have only one parent, respectively.
reduce_heads() must be avoided when 'git commit' is run after a 'git merge --no-ff --no-commit', otherwise it will turn the non-fast-forward merge into fast-forward. For the same reason, reduce_heads() must be avoided when amending such a merge commit.
To resolve this issue, 'git merge' will write info about whether fast-forward is allowed or not to $GIT_DIR/MERGE_MODE. Based on this info, 'git commit' will only perform reduce_heads() when it's committing a merge and fast-forward is enabled.
Also add test cases to ensure that non-fast-forward merges are committed and amended properly.
Signed-off-by: SZEDER Gábor <szeder@ira.uka.de> ---
I think this should be squashed onto Miklós' patch.
First, it fixes the segmentation fault caused by using the strbuf before initializing it. Second, amending a no-ff merge commit has the same issues with reduce_heads(); see the new test case. And the commit message is also more detailed ;)
I'm not sure about putting these two new test into t7600-merge.sh. Although the infrastructure to keep these tests very short (repo with branches already set up, verify_parents) is there available, the first test tests not only merge, but the cooperation of merge and commit, and this second one tests only commit.
Regards, Gábor
builtin-commit.c | 21 +++++++++++---------- t/t7600-merge.sh | 7 +++++++ 2 files changed, 18 insertions(+), 10 deletions(-)
diff --git a/builtin-commit.c b/builtin-commit.c index e69b4af..93f360f 100644 --- a/builtin-commit.c +++ b/builtin-commit.c @@ -953,6 +953,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix) return 1; } + strbuf_init(&sb, 0); /* Determine parents */ if (initial_commit) { reflog_msg = "commit (initial)"; @@ -986,22 +987,22 @@ int cmd_commit(int argc, const char **argv, const char *prefix) } fclose(fp); strbuf_release(&m); + if (!stat(git_path("MERGE_MODE"), &statbuf)) { + if (strbuf_read_file(&sb, git_path("MERGE_MODE"), 0) < 0) + die("could not read MERGE_MODE: %s", + strerror(errno)); + if (!strcmp(sb.buf, "no-ff")) + allow_fast_forward = 0; + } + if (allow_fast_forward) + parents = reduce_heads(parents); } else { reflog_msg = "commit"; pptr = &commit_list_insert(lookup_commit(head_sha1), pptr)->next; } - strbuf_reset(&sb); - if (!stat(git_path("MERGE_MODE"), &statbuf)) { - if (strbuf_read_file(&sb, git_path("MERGE_MODE"), 0) < 0) - die("could not read MERGE_MODE: %s", strerror(errno)); - if (!strcmp(sb.buf, "no-ff")) - allow_fast_forward = 0; - } - if (allow_fast_forward) - parents = reduce_heads(parents); /* Finally, get the commit message */ - strbuf_init(&sb, 0); + strbuf_reset(&sb); if (strbuf_read_file(&sb, git_path(commit_editmsg), 0) < 0) { rollback_index_files(); die("could not read commit message"); diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh index 98cfc53..209d7cd 100755 --- a/t/t7600-merge.sh +++ b/t/t7600-merge.sh @@ -520,4 +520,11 @@ test_expect_success 'merge --no-ff --no-commit && commit' ' test_debug 'gitk --all' +test_expect_success 'amending no-ff merge commit' ' + EDITOR=: git commit --amend && + verify_parents $c0 $c1 +' + +test_debug 'gitk --all' + test_done
-- 1.6.0.2.430.gfc53