From 35d2fffdb857836cc46f5a4ada525a246ddd5e11 Mon Sep 17 00:00:00 2001 From: Johan Herland Date: Tue, 9 Nov 2010 22:49:59 +0100 Subject: Provide 'git merge --abort' as a synonym to 'git reset --merge' Teach 'git merge' the --abort option, which verifies the existence of MERGE_HEAD and then invokes 'git reset --merge' to abort the current in-progress merge and attempt to reconstruct the pre-merge state. The reason for adding this option is to provide a user interface for aborting an in-progress merge that is consistent with the interface for aborting a rebase ('git rebase --abort'), aborting the application of a patch series ('git am --abort'), and aborting an in-progress notes merge ('git notes merge --abort'). The patch includes documentation and testcases that explain and verify the various scenarios in which 'git merge --abort' can run. The testcases also document the cases in which 'git merge --abort' is unable to correctly restore the pre-merge state (look for the '###' comments towards the bottom of t/t7609-merge-abort.sh). This patch has been improved by the following contributions: - Jonathan Nieder: Move test documentation into test_description Thanks-to: Jonathan Nieder Signed-off-by: Johan Herland Signed-off-by: Junio C Hamano diff --git a/Documentation/git-merge.txt b/Documentation/git-merge.txt index 84043cc..47b59a5 100644 --- a/Documentation/git-merge.txt +++ b/Documentation/git-merge.txt @@ -13,6 +13,7 @@ SYNOPSIS [-s ] [-X ] [--[no-]rerere-autoupdate] [-m ] ... 'git merge' HEAD ... +'git merge' --abort DESCRIPTION ----------- @@ -47,6 +48,14 @@ The second syntax ( `HEAD` ...) is supported for historical reasons. Do not use it from the command line or in new scripts. It is the same as `git merge -m ...`. +The third syntax ("`git merge --abort`") can only be run after the +merge has resulted in conflicts. 'git merge --abort' will abort the +merge process and try to reconstruct the pre-merge state. However, +if there were uncommitted changes when the merge started (and +especially if those changes were further modified after the merge +was started), 'git merge --abort' will in some cases be unable to +reconstruct the original (pre-merge) changes. Therefore: + *Warning*: Running 'git merge' with uncommitted changes is discouraged: while possible, it leaves you in a state that is hard to back out of in the case of a conflict. @@ -72,6 +81,18 @@ include::merge-options.txt[] Allow the rerere mechanism to update the index with the result of auto-conflict resolution if possible. +--abort:: + Abort the current conflict resolution process, and + try to reconstruct the pre-merge state. ++ +If there were uncommitted worktree changes present when the merge +started, 'git merge --abort' will in some cases be unable to +reconstruct these changes. It is therefore recommended to always +commit or stash your changes before running 'git merge'. ++ +'git merge --abort' is equivalent to 'git reset --merge' when +`MERGE_HEAD` is present. + ...:: Commits, usually other branch heads, to merge into our branch. You need at least one . Specifying more than one @@ -142,7 +163,7 @@ happens: i.e. matching `HEAD`. If you tried a merge which resulted in complex conflicts and -want to start over, you can recover with `git reset --merge`. +want to start over, you can recover with `git merge --abort`. HOW CONFLICTS ARE PRESENTED --------------------------- @@ -213,8 +234,8 @@ After seeing a conflict, you can do two things: * Decide not to merge. The only clean-ups you need are to reset the index file to the `HEAD` commit to reverse 2. and to clean - up working tree changes made by 2. and 3.; `git-reset --hard` can - be used for this. + up working tree changes made by 2. and 3.; `git merge --abort` + can be used for this. * Resolve the conflicts. Git will mark the conflicts in the working tree. Edit the files into shape and diff --git a/builtin/merge.c b/builtin/merge.c index 478a492..0539f7c 100644 --- a/builtin/merge.c +++ b/builtin/merge.c @@ -56,6 +56,7 @@ static size_t xopts_nr, xopts_alloc; static const char *branch; static int verbosity; static int allow_rerere_auto; +static int abort_current_merge; static struct strategy all_strategy[] = { { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL }, @@ -194,6 +195,8 @@ static struct option builtin_merge_options[] = { "message to be used for the merge commit (if any)", option_parse_message), OPT__VERBOSITY(&verbosity), + OPT_BOOLEAN(0, "abort", &abort_current_merge, + "abort the current in-progress merge"), OPT_END() }; @@ -914,6 +917,17 @@ int cmd_merge(int argc, const char **argv, const char *prefix) argc = parse_options(argc, argv, prefix, builtin_merge_options, builtin_merge_usage, 0); + if (abort_current_merge) { + int nargc = 2; + const char *nargv[] = {"reset", "--merge", NULL}; + + if (!file_exists(git_path("MERGE_HEAD"))) + die("There is no merge to abort (MERGE_HEAD missing)."); + + /* Invoke 'git reset --merge' */ + return cmd_reset(nargc, nargv, prefix); + } + if (read_cache_unmerged()) die_resolve_conflict("merge"); diff --git a/t/t7609-merge-abort.sh b/t/t7609-merge-abort.sh new file mode 100755 index 0000000..61890bc --- /dev/null +++ b/t/t7609-merge-abort.sh @@ -0,0 +1,313 @@ +#!/bin/sh + +test_description='test aborting in-progress merges + +Set up repo with conflicting and non-conflicting branches: + +There are three files foo/bar/baz, and the following graph illustrates the +content of these files in each commit: + +# foo/bar/baz --- foo/bar/bazz <-- master +# \ +# --- foo/barf/bazf <-- conflict_branch +# \ +# --- foo/bart/baz <-- clean_branch + +Next, test git merge --abort with the following variables: +- before/after successful merge (should fail when not in merge context) +- with/without conflicts +- clean/dirty index before merge +- clean/dirty worktree before merge +- dirty index before merge matches contents on remote branch +- changed/unchanged worktree after merge +- changed/unchanged index after merge +' +. ./test-lib.sh + +test_expect_success 'setup' ' + # Create the above repo + echo foo > foo && + echo bar > bar && + echo baz > baz && + git add foo bar baz && + git commit -m initial && + echo bazz > baz && + git commit -a -m "second" && + git checkout -b conflict_branch HEAD^ && + echo barf > bar && + echo bazf > baz && + git commit -a -m "conflict" && + git checkout -b clean_branch HEAD^ && + echo bart > bar && + git commit -a -m "clean" && + git checkout master +' + +pre_merge_head="$(git rev-parse HEAD)" + +test_expect_success 'fails without MERGE_HEAD (unstarted merge)' ' + test_must_fail git merge --abort 2>output && + grep -q MERGE_HEAD output && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" +' + +test_expect_success 'fails without MERGE_HEAD (completed merge)' ' + git merge clean_branch && + test ! -f .git/MERGE_HEAD && + # Merge successfully completed + post_merge_head="$(git rev-parse HEAD)" && + test_must_fail git merge --abort 2>output && + grep -q MERGE_HEAD output && + test ! -f .git/MERGE_HEAD && + test "$post_merge_head" = "$(git rev-parse HEAD)" +' + +test_expect_success 'Forget previous merge' ' + git reset --hard "$pre_merge_head" +' + +test_expect_success 'Abort after --no-commit' ' + # Redo merge, but stop before creating merge commit + git merge --no-commit clean_branch && + test -f .git/MERGE_HEAD && + # Abort non-conflicting merge + git merge --abort && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + test -z "$(git diff)" && + test -z "$(git diff --staged)" +' + +test_expect_success 'Abort after conflicts' ' + # Create conflicting merge + test_must_fail git merge conflict_branch && + test -f .git/MERGE_HEAD && + # Abort conflicting merge + git merge --abort && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + test -z "$(git diff)" && + test -z "$(git diff --staged)" +' + +test_expect_success 'Clean merge with dirty index fails' ' + echo xyzzy >> foo && + git add foo && + git diff --staged > expect && + test_must_fail git merge clean_branch && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + test -z "$(git diff)" && + git diff --staged > actual && + test_cmp expect actual +' + +test_expect_success 'Conflicting merge with dirty index fails' ' + test_must_fail git merge conflict_branch && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + test -z "$(git diff)" && + git diff --staged > actual && + test_cmp expect actual +' + +test_expect_success 'Reset index (but preserve worktree changes)' ' + git reset "$pre_merge_head" && + git diff > actual && + test_cmp expect actual +' + +test_expect_success 'Abort clean merge with non-conflicting dirty worktree' ' + git merge --no-commit clean_branch && + test -f .git/MERGE_HEAD && + # Abort merge + git merge --abort && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + test -z "$(git diff --staged)" && + git diff > actual && + test_cmp expect actual +' + +test_expect_success 'Abort conflicting merge with non-conflicting dirty worktree' ' + test_must_fail git merge conflict_branch && + test -f .git/MERGE_HEAD && + # Abort merge + git merge --abort && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + test -z "$(git diff --staged)" && + git diff > actual && + test_cmp expect actual +' + +test_expect_success 'Reset worktree changes' ' + git reset --hard "$pre_merge_head" +' + +test_expect_success 'Fail clean merge with conflicting dirty worktree' ' + echo xyzzy >> bar && + git diff > expect && + test_must_fail git merge --no-commit clean_branch && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + test -z "$(git diff --staged)" && + git diff > actual && + test_cmp expect actual +' + +test_expect_success 'Fail conflicting merge with conflicting dirty worktree' ' + test_must_fail git merge conflict_branch && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + test -z "$(git diff --staged)" && + git diff > actual && + test_cmp expect actual +' + +test_expect_success 'Reset worktree changes' ' + git reset --hard "$pre_merge_head" +' + +test_expect_success 'Fail clean merge with matching dirty worktree' ' + echo bart > bar && + git diff > expect && + test_must_fail git merge --no-commit clean_branch && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + test -z "$(git diff --staged)" && + git diff > actual && + test_cmp expect actual +' + +test_expect_success 'Abort clean merge with matching dirty index' ' + git add bar && + git diff --staged > expect && + git merge --no-commit clean_branch && + test -f .git/MERGE_HEAD && + ### When aborting the merge, git will discard all staged changes, + ### including those that were staged pre-merge. In other words, + ### --abort will LOSE any staged changes (the staged changes that + ### are lost must match the merge result, or the merge would not + ### have been allowed to start). Change expectations accordingly: + rm expect && + touch expect && + # Abort merge + git merge --abort && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + git diff --staged > actual && + test_cmp expect actual && + test -z "$(git diff)" +' + +test_expect_success 'Reset worktree changes' ' + git reset --hard "$pre_merge_head" +' + +test_expect_success 'Fail conflicting merge with matching dirty worktree' ' + echo barf > bar && + git diff > expect && + test_must_fail git merge conflict_branch && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + test -z "$(git diff --staged)" && + git diff > actual && + test_cmp expect actual +' + +test_expect_success 'Abort conflicting merge with matching dirty index' ' + git add bar && + git diff --staged > expect && + test_must_fail git merge conflict_branch && + test -f .git/MERGE_HEAD && + ### When aborting the merge, git will discard all staged changes, + ### including those that were staged pre-merge. In other words, + ### --abort will LOSE any staged changes (the staged changes that + ### are lost must match the merge result, or the merge would not + ### have been allowed to start). Change expectations accordingly: + rm expect && + touch expect && + # Abort merge + git merge --abort && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + git diff --staged > actual && + test_cmp expect actual && + test -z "$(git diff)" +' + +test_expect_success 'Reset worktree changes' ' + git reset --hard "$pre_merge_head" +' + +test_expect_success 'Abort merge with pre- and post-merge worktree changes' ' + # Pre-merge worktree changes + echo xyzzy > foo && + echo barf > bar && + git add bar && + git diff > expect && + git diff --staged > expect-staged && + # Perform merge + test_must_fail git merge conflict_branch && + test -f .git/MERGE_HEAD && + # Post-merge worktree changes + echo yzxxz > foo && + echo blech > baz && + ### When aborting the merge, git will discard staged changes (bar) + ### and unmerged changes (baz). Other changes that are neither + ### staged nor marked as unmerged (foo), will be preserved. For + ### these changed, git cannot tell pre-merge changes apart from + ### post-merge changes, so the post-merge changes will be + ### preserved. Change expectations accordingly: + git diff -- foo > expect && + rm expect-staged && + touch expect-staged && + # Abort merge + git merge --abort && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + git diff > actual && + test_cmp expect actual && + git diff --staged > actual-staged && + test_cmp expect-staged actual-staged +' + +test_expect_success 'Reset worktree changes' ' + git reset --hard "$pre_merge_head" +' + +test_expect_success 'Abort merge with pre- and post-merge index changes' ' + # Pre-merge worktree changes + echo xyzzy > foo && + echo barf > bar && + git add bar && + git diff > expect && + git diff --staged > expect-staged && + # Perform merge + test_must_fail git merge conflict_branch && + test -f .git/MERGE_HEAD && + # Post-merge worktree changes + echo yzxxz > foo && + echo blech > baz && + git add foo bar && + ### When aborting the merge, git will discard all staged changes + ### (foo, bar and baz), and no changes will be preserved. Whether + ### the changes were staged pre- or post-merge does not matter + ### (except for not preventing starting the merge). + ### Change expectations accordingly: + rm expect expect-staged && + touch expect && + touch expect-staged && + # Abort merge + git merge --abort && + test ! -f .git/MERGE_HEAD && + test "$pre_merge_head" = "$(git rev-parse HEAD)" && + git diff > actual && + test_cmp expect actual && + git diff --staged > actual-staged && + test_cmp expect-staged actual-staged +' + +test_done -- cgit v0.10.2-6-g49f6