[PATCH v4 0/4] pre-merge-commit hook

[Josh Steadmon <steadmon@google.com>]

This series adds a new pre-merge-commit hook, similar in usage to
pre-commit. It also improves hook testing in t7503, by verifying that
the correct hooks are run or bypassed as expected.

The original series was done by Michael J Gruber <git@grubix.eu>. I have
addressed the outstanding review comments, and noted my changes in the
commit messages in "[js: ...]" blocks.

Changes since V3:
* Applied several test style fixes suggested by Martin (thanks!).
* Clarified the documentation for pre-merge-commit hook.
* Fixed a few cases where testing that the merge hook did not run might
  erroneously succeed if we don't have any merge to actually perform.
* Simplified test cleanup by adding a new non-executable sample hook
  script.
* Added test cases for non-executable pre-merge-commit hooks.

Changes since V2:
* Renamed the hook from "pre-merge" to "pre-merge-commit".
* Added a new patch (1/4) to improve t7503 by verifying that the
  expected hooks are (or are not) run.
* Squashed test changes (from V2's patch 4/4) into patch 3/4.
  Modified the tests to follow the example set in patch 1/4.
* Reworded commit messages to match with the current state of certain
  flags, which changed in between V1 and V2 of this series.

Josh Steadmon (1):
  t7503: verify proper hook execution

Michael J Gruber (3):
  merge: do no-verify like commit
  git-merge: honor pre-merge-commit hook
  merge: --no-verify to bypass pre-merge-commit hook

 Documentation/git-merge.txt                   |   2 +-
 Documentation/githooks.txt                    |  22 ++
 Documentation/merge-options.txt               |   4 +
 builtin/merge.c                               |  18 +-
 ...3-pre-commit-and-pre-merge-commit-hooks.sh | 281 ++++++++++++++++++
 t/t7503-pre-commit-hook.sh                    | 139 ---------
 templates/hooks--pre-merge-commit.sample      |  13 +
 7 files changed, 336 insertions(+), 143 deletions(-)
 create mode 100755 t/t7503-pre-commit-and-pre-merge-commit-hooks.sh
 delete mode 100755 t/t7503-pre-commit-hook.sh
 create mode 100755 templates/hooks--pre-merge-commit.sample

Range-diff against v3:
1:  f0476b2b1e ! 1:  5085729095 t7503: verify proper hook execution
    @@ Commit message
         write_script() and doing setup inside a test_expect_success block.
     
    +    Improved-by: Martin Ågren <martin.agren@gmail.com>
    +    Signed-off-by: Martin Ågren <martin.agren@gmail.com>
     
      ## t/t7503-pre-commit-hook.sh ##
     @@ t/t7503-pre-commit-hook.sh: test_description='pre-commit hook'
    @@ t/t7503-pre-commit-hook.sh: test_description='pre-commit hook'
     +	echo $0 >>actual_hooks
     +	exit 1
     +	EOF
    ++	write_script "$HOOKDIR/non-exec.sample" <<-\EOF &&
    ++	echo $0 >>actual_hooks
    ++	exit 1
    ++	EOF
    ++	chmod -x "$HOOKDIR/non-exec.sample" &&
     +	write_script "$HOOKDIR/require-prefix.sample" <<-\EOF &&
     +	echo $0 >>actual_hooks
     +	test $GIT_PREFIX = "success/"
    @@ t/t7503-pre-commit-hook.sh: test_description='pre-commit hook'
      
     -	echo "foo" > file &&
     +test_expect_success 'with no hook' '
    -+	test_when_finished "rm -f expected_hooks actual_hooks" &&
    -+	touch expected_hooks actual_hooks &&
    ++	test_when_finished "rm -f actual_hooks" &&
     +	echo "foo" >file &&
      	git add file &&
     -	git commit -m "first"
     -
     +	git commit -m "first" &&
    -+	test_cmp expected_hooks actual_hooks
    ++	test_path_is_missing actual_hooks
      '
      
      test_expect_success '--no-verify with no hook' '
     -
     -	echo "bar" > file &&
    -+	test_when_finished "rm -f expected_hooks actual_hooks" &&
    -+	touch expected_hooks actual_hooks &&
    ++	test_when_finished "rm -f actual_hooks" &&
     +	echo "bar" >file &&
      	git add file &&
     -	git commit --no-verify -m "bar"
     -
     +	git commit --no-verify -m "bar" &&
    -+	test_cmp expected_hooks actual_hooks
    ++	test_path_is_missing actual_hooks
      '
      
     -# now install hook that always succeeds
    @@ t/t7503-pre-commit-hook.sh: test_description='pre-commit hook'
     -	echo "more" >> file &&
     +	test_when_finished "rm -f \"$PRECOMMIT\" expected_hooks actual_hooks" &&
     +	ln -s "success.sample" "$PRECOMMIT" &&
    -+	touch actual_hooks &&
     +	echo "$PRECOMMIT" >expected_hooks &&
     +	echo "more" >>file &&
      	git add file &&
    @@ t/t7503-pre-commit-hook.sh: test_description='pre-commit hook'
      test_expect_success '--no-verify with succeeding hook' '
     -
     -	echo "even more" >> file &&
    -+	test_when_finished "rm -f \"$PRECOMMIT\" expected_hooks actual_hooks" &&
    ++	test_when_finished "rm -f \"$PRECOMMIT\" actual_hooks" &&
     +	ln -s "success.sample" "$PRECOMMIT" &&
    -+	touch expected_hooks actual_hooks &&
     +	echo "even more" >>file &&
      	git add file &&
     -	git commit --no-verify -m "even more"
     -
     +	git commit --no-verify -m "even more" &&
    -+	test_cmp expected_hooks actual_hooks
    ++	test_path_is_missing actual_hooks
      '
      
     -# now a hook that fails
    @@ t/t7503-pre-commit-hook.sh: test_description='pre-commit hook'
     -	echo "another" >> file &&
     +	test_when_finished "rm -f \"$PRECOMMIT\" expected_hooks actual_hooks" &&
     +	ln -s "fail.sample" "$PRECOMMIT" &&
    -+	touch actual_hooks &&
     +	echo "$PRECOMMIT" >expected_hooks &&
     +	echo "another" >>file &&
      	git add file &&
    @@ t/t7503-pre-commit-hook.sh: test_description='pre-commit hook'
      test_expect_success '--no-verify with failing hook' '
     -
     -	echo "stuff" >> file &&
    -+	test_when_finished "rm -f \"$PRECOMMIT\" expected_hooks actual_hooks" &&
    ++	test_when_finished "rm -f \"$PRECOMMIT\" actual_hooks" &&
     +	ln -s "fail.sample" "$PRECOMMIT" &&
    -+	touch expected_hooks actual_hooks &&
     +	echo "stuff" >>file &&
      	git add file &&
     -	git commit --no-verify -m "stuff"
     -
     +	git commit --no-verify -m "stuff" &&
    -+	test_cmp expected_hooks actual_hooks
    ++	test_path_is_missing actual_hooks
      '
      
     -chmod -x "$HOOK"
      test_expect_success POSIXPERM 'with non-executable hook' '
     -
     -	echo "content" >> file &&
    -+	test_when_finished "rm -f \"$PRECOMMIT\" expected_hooks actual_hooks; chmod +x \"$HOOKDIR/fail.sample\"" &&
    -+	ln -s "fail.sample" "$PRECOMMIT" &&
    -+	chmod -x "$HOOKDIR/fail.sample" &&
    -+	touch expected_hooks actual_hooks &&
    ++	test_when_finished "rm -f \"$PRECOMMIT\" actual_hooks" &&
    ++	ln -s "non-exec.sample" "$PRECOMMIT" &&
     +	echo "content" >>file &&
      	git add file &&
     -	git commit -m "content"
     -
     +	git commit -m "content" &&
    -+	test_cmp expected_hooks actual_hooks
    ++	test_path_is_missing actual_hooks
      '
      
      test_expect_success POSIXPERM '--no-verify with non-executable hook' '
     -
     -	echo "more content" >> file &&
    -+	test_when_finished "rm -f \"$PRECOMMIT\" expected_hooks actual_hooks; chmod +x \"$HOOKDIR/fail.sample\"" &&
    -+	ln -s "fail.sample" "$PRECOMMIT" &&
    -+	chmod -x "$HOOKDIR/fail.sample" &&
    -+	touch expected_hooks actual_hooks &&
    ++	test_when_finished "rm -f \"$PRECOMMIT\" actual_hooks" &&
    ++	ln -s "non-exec.sample" "$PRECOMMIT" &&
     +	echo "more content" >>file &&
      	git add file &&
     -	git commit --no-verify -m "more content"
     -
     +	git commit --no-verify -m "more content" &&
    -+	test_cmp expected_hooks actual_hooks
    ++	test_path_is_missing actual_hooks
      '
     -chmod +x "$HOOK"
     -
2:  89ddbf410f = 2:  3b701a5c41 merge: do no-verify like commit
3:  61b989ff16 ! 3:  9210421fbb git-merge: honor pre-merge-commit hook
    @@ Commit message
     
         [js: * renamed hook from "pre-merge" to "pre-merge-commit"
              * only discard the index if the hook is actually present
    +         * expanded githooks documentation entry
              * clarified that hook should write messages to stderr
              * squashed test changes from the original series' patch 4/4
              * modified tests to follow new pattern from this series' patch 1/4
    +         * added a test case for non-executable merge hooks
    +         * added a test case for failed merges
    +         * when testing that the merge hook did not run, make sure we
    +           actually have a merge to perform (by resetting the "side" branch
    +           to its original state).
              * reworded commit message
         ]
     
    +    Improved-by: Martin Ågren <martin.agren@gmail.com>
         Signed-off-by: Michael J Gruber <git@grubix.eu>
    +    Signed-off-by: Martin Ågren <martin.agren@gmail.com>
     
      ## Documentation/githooks.txt ##
    @@ Documentation/githooks.txt: The default 'pre-commit' hook, when enabled--and wit
     +pre-merge-commit
     +~~~~~~~~~~~~~~~~
     +
    -+This hook is invoked by 'git merge' when doing an automatic merge
    -+commit; it is equivalent to 'pre-commit' for a non-automatic commit
    -+for a merge.
    ++This hook is invoked by linkgit:git-merge[1]. It takes no parameters, and is
    ++invoked after the merge has been carried out successfully and before
    ++obtaining the proposed commit log message to
    ++make a commit.  Exiting with a non-zero status from this script
    ++causes the `git merge` command to abort before creating a commit.
    ++
    ++The default 'pre-merge-commit' hook, when enabled, runs the
    ++'pre-commit' hook, if the latter is enabled.
    ++
    ++This hook is invoked with the environment variable
    ++`GIT_EDITOR=:` if the command will not bring up an editor
    ++to modify the commit message.
    ++
    ++If the merge cannot be carried out automatically, the conflicts
    ++need to be resolved and the result committed separately (see
    ++linkgit:git-merge[1]). At that point, this hook will not be executed,
    ++but the 'pre-commit' hook will, if it is enabled.
     +
      prepare-commit-msg
      ~~~~~~~~~~~~~~~~~~
    @@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success 'sample sc
      '
      
     +test_expect_success 'root commit' '
    -+	echo "root" > file &&
    ++	echo "root" >file &&
     +	git add file &&
     +	git commit -m "zeroth" &&
     +	git checkout -b side &&
    -+	echo "foo" > foo &&
    ++	echo "foo" >foo &&
     +	git add foo &&
     +	git commit -m "make it non-ff" &&
    ++	git branch side-orig side &&
     +	git checkout master
     +'
    ++
    ++test_expect_success 'setup conflicting branches' '
    ++	test_when_finished "git checkout master" &&
    ++	git checkout -b conflicting-a master &&
    ++	echo a >conflicting &&
    ++	git add conflicting &&
    ++	git commit -m conflicting-a &&
    ++	git checkout -b conflicting-b master &&
    ++	echo b >conflicting &&
    ++	git add conflicting &&
    ++	git commit -m conflicting-b
    ++'
     +
      test_expect_success 'with no hook' '
    - 	test_when_finished "rm -f expected_hooks actual_hooks" &&
    - 	touch expected_hooks actual_hooks &&
    + 	test_when_finished "rm -f actual_hooks" &&
    + 	echo "foo" >file &&
     @@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success 'with no hook' '
    - 	test_cmp expected_hooks actual_hooks
    + 	test_path_is_missing actual_hooks
      '
      
     +test_expect_success 'with no hook (merge)' '
    -+	test_when_finished "rm -f expected_hooks actual_hooks" &&
    -+	touch expected_hooks actual_hooks &&
    ++	test_when_finished "rm -f actual_hooks" &&
    ++	git branch -f side side-orig &&
     +	git checkout side &&
     +	git merge -m "merge master" master &&
     +	git checkout master &&
    -+	test_cmp expected_hooks actual_hooks
    ++	test_path_is_missing actual_hooks
     +'
     +
      test_expect_success '--no-verify with no hook' '
    - 	test_when_finished "rm -f expected_hooks actual_hooks" &&
    - 	touch expected_hooks actual_hooks &&
    + 	test_when_finished "rm -f actual_hooks" &&
    + 	echo "bar" >file &&
     @@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success 'with succeeding hook' '
      	test_cmp expected_hooks actual_hooks
      '
    @@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success 'with succ
     +test_expect_success 'with succeeding hook (merge)' '
     +	test_when_finished "rm -f \"$PREMERGE\" expected_hooks actual_hooks" &&
     +	ln -s "success.sample" "$PREMERGE" &&
    -+	touch actual_hooks &&
     +	echo "$PREMERGE" >expected_hooks &&
     +	git checkout side &&
     +	git merge -m "merge master" master &&
     +	git checkout master &&
     +	test_cmp expected_hooks actual_hooks
     +'
    ++
    ++test_expect_success 'automatic merge fails; both hooks are available' '
    ++	test_when_finished "rm -f \"$PREMERGE\" \"$PRECOMMIT\"" &&
    ++	test_when_finished "rm -f expected_hooks actual_hooks" &&
    ++	test_when_finished "git checkout master" &&
    ++	ln -s "success.sample" "$PREMERGE" &&
    ++	ln -s "success.sample" "$PRECOMMIT" &&
    ++
    ++	git checkout conflicting-a &&
    ++	test_must_fail git merge -m "merge conflicting-b" conflicting-b &&
    ++	test_path_is_missing actual_hooks &&
    ++
    ++	echo "$PRECOMMIT" >expected_hooks &&
    ++	echo a+b >conflicting &&
    ++	git add conflicting &&
    ++	git commit -m "resolve conflict" &&
    ++	test_cmp expected_hooks actual_hooks
    ++'
     +
      test_expect_success '--no-verify with succeeding hook' '
    - 	test_when_finished "rm -f \"$PRECOMMIT\" expected_hooks actual_hooks" &&
    + 	test_when_finished "rm -f \"$PRECOMMIT\" actual_hooks" &&
      	ln -s "success.sample" "$PRECOMMIT" &&
     @@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success '--no-verify with failing hook' '
    - 	test_cmp expected_hooks actual_hooks
    + 	test_path_is_missing actual_hooks
      '
      
     +test_expect_success 'with failing hook (merge)' '
     +	test_when_finished "rm -f \"$PREMERGE\" expected_hooks actual_hooks" &&
     +	ln -s "fail.sample" "$PREMERGE" &&
    -+	touch actual_hooks &&
     +	echo "$PREMERGE" >expected_hooks &&
     +	git checkout side &&
     +	test_must_fail git merge -m "merge master" master &&
    @@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success '--no-veri
     +'
     +
      test_expect_success POSIXPERM 'with non-executable hook' '
    - 	test_when_finished "rm -f \"$PRECOMMIT\" expected_hooks actual_hooks; chmod +x \"$HOOKDIR/fail.sample\"" &&
    - 	ln -s "fail.sample" "$PRECOMMIT" &&
    + 	test_when_finished "rm -f \"$PRECOMMIT\" actual_hooks" &&
    + 	ln -s "non-exec.sample" "$PRECOMMIT" &&
    +@@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success POSIXPERM '--no-verify with non-executable hook' '
    + 	test_path_is_missing actual_hooks
    + '
    + 
    ++test_expect_success POSIXPERM 'with non-executable hook (merge)' '
    ++	test_when_finished "rm -f \"$PREMERGE\" actual_hooks" &&
    ++	ln -s "non-exec.sample" "$PREMERGE" &&
    ++	git branch -f side side-orig &&
    ++	git checkout side &&
    ++	git merge -m "merge master" master &&
    ++	git checkout master &&
    ++	test_path_is_missing actual_hooks
    ++'
    ++
    + test_expect_success 'with hook requiring GIT_PREFIX' '
    + 	test_when_finished "rm -rf \"$PRECOMMIT\" expected_hooks actual_hooks success" &&
    + 	ln -s "require-prefix.sample" "$PRECOMMIT" &&
     
      ## templates/hooks--pre-merge-commit.sample (new) ##
     @@
4:  45828c56fc ! 4:  96c54883d3 merge: --no-verify to bypass pre-merge-commit hook
    @@ Commit message
              * cleaned up trailing whitespace
              * squashed test changes from the original series' patch 4/4
              * modified tests to follow pattern from this series' patch 1/4
    +         * added a test case for --no-verify with non-executable hook
    +         * when testing that the merge hook did not run, make sure we
    +           actually have a merge to perform (by resetting the "side" branch
    +           to its original state).
    +
         ]
     
    +    Improved-by: Martin Ågren <martin.agren@gmail.com>
         Signed-off-by: Michael J Gruber <git@grubix.eu>
    +    Signed-off-by: Martin Ågren <martin.agren@gmail.com>
     
      ## Documentation/githooks.txt ##
    -@@ Documentation/githooks.txt: pre-merge-commit
    - 
    - This hook is invoked by 'git merge' when doing an automatic merge
    - commit; it is equivalent to 'pre-commit' for a non-automatic commit
    --for a merge.
    -+for a merge, and can be bypassed with the `--no-verify` option.
    +@@ Documentation/githooks.txt: the use of non-ASCII filenames.
    + pre-merge-commit
    + ~~~~~~~~~~~~~~~~
      
    - prepare-commit-msg
    - ~~~~~~~~~~~~~~~~~~
    +-This hook is invoked by linkgit:git-merge[1]. It takes no parameters, and is
    ++This hook is invoked by linkgit:git-merge[1], and can be bypassed
    ++with the `--no-verify` option.  It takes no parameters, and is
    + invoked after the merge has been carried out successfully and before
    + obtaining the proposed commit log message to
    + make a commit.  Exiting with a non-zero status from this script
     
      ## builtin/merge.c ##
     @@ builtin/merge.c: static struct option builtin_merge_options[] = {
    @@ builtin/merge.c: static void prepare_to_commit(struct commit_list *remoteheads)
     
      ## t/t7503-pre-commit-and-pre-merge-commit-hooks.sh ##
     @@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success '--no-verify with no hook' '
    - 	test_cmp expected_hooks actual_hooks
    + 	test_path_is_missing actual_hooks
      '
      
     +test_expect_success '--no-verify with no hook (merge)' '
    -+	test_when_finished "rm -f expected_hooks actual_hooks" &&
    -+	touch expected_hooks actual_hooks &&
    ++	test_when_finished "rm -f actual_hooks" &&
    ++	git branch -f side side-orig &&
     +	git checkout side &&
     +	git merge --no-verify -m "merge master" master &&
     +	git checkout master &&
    -+	test_cmp expected_hooks actual_hooks
    ++	test_path_is_missing actual_hooks
     +'
     +
      test_expect_success 'with succeeding hook' '
      	test_when_finished "rm -f \"$PRECOMMIT\" expected_hooks actual_hooks" &&
      	ln -s "success.sample" "$PRECOMMIT" &&
     @@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success '--no-verify with succeeding hook' '
    - 	test_cmp expected_hooks actual_hooks
    + 	test_path_is_missing actual_hooks
      '
      
     +test_expect_success '--no-verify with succeeding hook (merge)' '
    -+	test_when_finished "rm -f \"$PREMERGE\" expected_hooks actual_hooks" &&
    ++	test_when_finished "rm -f \"$PREMERGE\" actual_hooks" &&
     +	ln -s "success.sample" "$PREMERGE" &&
    -+	touch expected_hooks actual_hooks &&
    ++	git branch -f side side-orig &&
     +	git checkout side &&
     +	git merge --no-verify -m "merge master" master &&
     +	git checkout master &&
    -+	test_cmp expected_hooks actual_hooks
    ++	test_path_is_missing actual_hooks
     +'
     +
      test_expect_success 'with failing hook' '
    @@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success 'with fail
      '
      
     +test_expect_success '--no-verify with failing hook (merge)' '
    -+	test_when_finished "rm -f \"$PREMERGE\" expected_hooks actual_hooks" &&
    ++	test_when_finished "rm -f \"$PREMERGE\" actual_hooks" &&
     +	ln -s "fail.sample" "$PREMERGE" &&
    -+	touch expected_hooks actual_hooks &&
    ++	git branch -f side side-orig &&
     +	git checkout side &&
     +	git merge --no-verify -m "merge master" master &&
     +	git checkout master &&
    -+	test_cmp expected_hooks actual_hooks
    ++	test_path_is_missing actual_hooks
     +'
     +
      test_expect_success POSIXPERM 'with non-executable hook' '
    - 	test_when_finished "rm -f \"$PRECOMMIT\" expected_hooks actual_hooks; chmod +x \"$HOOKDIR/fail.sample\"" &&
    - 	ln -s "fail.sample" "$PRECOMMIT" &&
    + 	test_when_finished "rm -f \"$PRECOMMIT\" actual_hooks" &&
    + 	ln -s "non-exec.sample" "$PRECOMMIT" &&
    +@@ t/t7503-pre-commit-and-pre-merge-commit-hooks.sh: test_expect_success POSIXPERM 'with non-executable hook (merge)' '
    + 	test_path_is_missing actual_hooks
    + '
    + 
    ++test_expect_success POSIXPERM '--no-verify with non-executable hook (merge)' '
    ++	test_when_finished "rm -f \"$PREMERGE\" actual_hooks" &&
    ++	ln -s "non-exec.sample" "$PREMERGE" &&
    ++	git branch -f side side-orig &&
    ++	git checkout side &&
    ++	git merge --no-verify -m "merge master" master &&
    ++	git checkout master &&
    ++	test_path_is_missing actual_hooks
    ++'
    ++
    + test_expect_success 'with hook requiring GIT_PREFIX' '
    + 	test_when_finished "rm -rf \"$PRECOMMIT\" expected_hooks actual_hooks success" &&
    + 	ln -s "require-prefix.sample" "$PRECOMMIT" &&
-- 
2.22.0.770.g0f2c4a37fd-goog