[PATCH] git-merge: add option --no-ff
- From
- Lars Hjemli <hjemli@gmail.com>
- Date
- Sep 17, 2007, 16:23 UTC
- Message-ID
- <11900461843997-git-send-email-hjemli@gmail.com>
- In-Reply-To
- <8c5c35580709170817s467fa7dv375952f872bba0e3@mail.gmail.com>
This option forces fast-forward merges to create a "true" merge commit, i.e. a commit with multiple parents.
Although a fast-forward merge would normally be the right thing to do with git branches, it is suboptimal when operating on git-svn branches since it makes 'git-svn dcommit' fail to recognize the correct upstream subversion branch. But performing such a merge with --no-ff specified will both make git-svn dcommit recognize the correct upstream and create the logically correct history in subversion (the merge performed in git will be recorded as a single revision in subversion, not as a series of revisions seemingly cherry-picked from the merged branch).
Signed-off-by: Lars Hjemli <hjemli@gmail.com> ---
When updating git-svn.txt, I noticed that we might want to update the section "DESIGN PHILOSOPHY". Eric?
Documentation/git-svn.txt | 13 +++++++++++++ Documentation/merge-options.txt | 5 +++++ git-merge.sh | 13 +++++++++++-- t/t6028-merge-up-to-date.sh | 25 +++++++++++++++++++++++++ 4 files changed, 54 insertions(+), 2 deletions(-)
diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt index be2e34e..c510c21 100644 --- a/Documentation/git-svn.txt +++ b/Documentation/git-svn.txt @@ -475,6 +475,19 @@ use 'git-svn rebase' to update your work branch instead of 'git pull' or when committing into SVN, which can lead to merge commits reversing previous commits in SVN. +If you use 'git-svn dcommit' to commit your local work to the upstream +subversion branch, merge commits are usually handled correctly, i.e. +git-svn will only follow the first parent of each merge commit and create +a single subversion revision for each of them. An exception is when two +subversion branches has been merged locally and the merge ended up as a +fast-forward operation. This will make git-svn belive that there are no +local changes to dcommit. To work around this issue, one can redo the +merge using the --no-ff option: + + $ git reset --hard HEAD@{1} ## undo the fast-forward merge + $ git merge --no-ff <branch> + + DESIGN PHILOSOPHY ----------------- Merge tracking in Subversion is lacking and doing branched development diff --git a/Documentation/merge-options.txt b/Documentation/merge-options.txt index d64c259..b34b888 100644 --- a/Documentation/merge-options.txt +++ b/Documentation/merge-options.txt @@ -25,3 +25,8 @@ If there is no `-s` option, a built-in list of strategies is used instead (`git-merge-recursive` when merging a single head, `git-merge-octopus` otherwise). + +--no-ff:: + Force the creation of a merge commit even when the merge would + have resolved as a fast-forward operation. See gitlink:git-svn[1] + for a use-case for this option. diff --git a/git-merge.sh b/git-merge.sh index 3a01db0..13b98e6 100755 --- a/git-merge.sh +++ b/git-merge.sh @@ -3,7 +3,7 @@ # Copyright (c) 2005 Junio C Hamano # -USAGE='[-n] [--summary] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+' +USAGE='[-n] [--summary] [--no-commit] [--no-ff] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+' SUBDIRECTORY_OK=Yes . git-sh-setup @@ -165,6 +165,10 @@ do merge_msg="$1" have_message=t ;; + --no-ff) + no_ff=t + no_fast_forward_strategies=$all_strategies + ;; -*) usage ;; *) break ;; esac @@ -444,7 +448,12 @@ done # auto resolved the merge cleanly. if test '' != "$result_tree" then - parents=$(git show-branch --independent "$head" "$@" | sed -e 's/^/-p /') + if test $no_ff = 't' + then + parents=$(git rev-parse "$head" "$@" | sed -e 's/^/-p /') + else + parents=$(git show-branch --independent "$head" "$@" | sed -e 's/^/-p /') + fi result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit finish "$result_commit" "Merge made by $wt_strategy." dropsave diff --git a/t/t6028-merge-up-to-date.sh b/t/t6028-merge-up-to-date.sh index f8f3e3f..afd74e2 100755 --- a/t/t6028-merge-up-to-date.sh +++ b/t/t6028-merge-up-to-date.sh @@ -10,12 +10,14 @@ test_expect_success setup ' test_tick && git commit -m initial && git tag c0 && + c0=$(git rev-parse c0) echo second >file && git add file && test_tick && git commit -m second && git tag c1 && + c1=$(git rev-parse c1) git branch test ' @@ -41,6 +43,16 @@ test_expect_success 'merge -s recursive fast-forward' ' ' +test_expect_success 'merge -s recursive --no-ff' ' + + git reset --hard c0 && + test_tick && + git merge -s recursive --no-ff c1 && + test $c0 = $(git rev-parse HEAD^1) && + test $c1 = $(git rev-parse HEAD^2) + +' + test_expect_success 'merge -s ours up-to-date' ' git reset --hard c1 && @@ -63,6 +75,19 @@ test_expect_success 'merge -s ours fast-forward' ' ' +test_expect_success 'merge -s ours --no-ff' ' + + git reset --hard c0 && + test_tick && + git merge -s ours --no-ff c1 && + expect=$(git rev-parse c0^{tree}) && + current=$(git rev-parse HEAD^{tree}) && + test "$expect" = "$current" && + test $c0 = $(git rev-parse HEAD^1) && + test $c1 = $(git rev-parse HEAD^2) + +' + test_expect_success 'merge -s subtree up-to-date' ' git reset --hard c1 &&
-- 1.5.3.1.92.g2f5e