Thread (1 message) 1 message, 1 author, 2018-07-17

Re: [PATCH v3 1/3] t7501: add merge conflict tests for dry run

From: Junio C Hamano <hidden>
Date: 2018-07-17 17:05:57

Samuel Lijin [off-list ref] writes:
The behavior of git commit when doing a dry run changes if there are
unfixed/fixed merge conflits, but the test suite currently only asserts
that `git commit --dry-run` succeeds when all merge conflicts are fixed.

Add tests to document the behavior of all flags which imply a dry run
when (1) there is at least one unfixed merge conflict and (2) when all
merge conflicts are all fixed.
s/conflits/conflicts/
s/fixed/resolved/g	(both above and in the patch text)
s/unfixed/unresolved/g  (both above and in the patch text)
quoted hunk
Signed-off-by: Samuel Lijin <redacted>
---
 t/t7501-commit.sh | 45 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 40 insertions(+), 5 deletions(-)
diff --git a/t/t7501-commit.sh b/t/t7501-commit.sh
index fa61b1a4e..be087e73f 100755
--- a/t/t7501-commit.sh
+++ b/t/t7501-commit.sh
@@ -652,7 +652,8 @@ test_expect_success '--only works on to-be-born branch' '
 	test_cmp expected actual
 '
 
-test_expect_success '--dry-run with conflicts fixed from a merge' '
+# set up env for tests of --dry-run given fixed/unfixed merge conflicts
+test_expect_success 'setup env with unfixed merge conflicts' '
 	# setup two branches with conflicting information
 	# in the same file, resolve the conflict,
 	# call commit with --dry-run
@@ -665,11 +666,45 @@ test_expect_success '--dry-run with conflicts fixed from a merge' '
 	git checkout -b branch-2 HEAD^1 &&
 	echo "commit-2-state" >test-file &&
 	git commit -m "commit 2" -i test-file &&
-	! $(git merge --no-commit commit-1) &&
-	echo "commit-2-state" >test-file &&
+	test_expect_code 1 git merge --no-commit commit-1
The original is bad and also embarrassing.  Whatever comes out of
the standard output of "git merge" is $IFS split and executed as a
shell command (which likely results in "no such command" failure)
and it tries to make sure that a failure happens.

The right way to write that line (without your enhancement in this
patch) would have been:

	test_must_fail git merge --no-commit commit-1 &&

I doubt it is a good idea to hardcode exit status of 1 by using
test_expect_code, though.  "git merge --help" does not say anything
about "1 means this failure, 2 means that failure, 3 means that
other failure".  And my quick forward scan of this series does not
tell me that you are trying to declare that from here on we _will_
make that promise to the end users by carving the exit status(es) in
stone.  The same about "git commit"'s exit code in the following
four tests.
+'
+
+test_expect_success '--dry-run with unfixed merge conflicts' '
+	test_expect_code 1 git commit --dry-run
+'
+
+test_expect_success '--short with unfixed merge conflicts' '
+	test_expect_code 1 git commit --short
+'
+
+test_expect_success '--porcelain with unfixed merge conflicts' '
+	test_expect_code 1 git commit --porcelain
+'
+
+test_expect_success '--long with unfixed merge conflicts' '
+	test_expect_code 1 git commit --long
+'
+
+test_expect_success '--dry-run with conflicts fixed from a merge' '
+	echo "merge-conflicts-fixed" >test-file &&
The original test pretended that we resolved favouring the current
state with "commit-2-state" in the file, as if we ran "-s ours".
Is there a reason why we now use a different contents, or is this
just a change based on subjective preference?  

    Not saying that the latter is necessrily bad; just trying to
    understand why we are making this change.
 	git add test-file &&
-	git commit --dry-run &&
-	git commit -m "conflicts fixed from merge."
+	git commit --dry-run
OK, the original tried --dry-run to ensure it exited with 0 status
(i.e. have something to commit) and then did a commit to record the
updated state with a message.  You are checking only the dry-run
part, leaving the check of the final commit's status to another
test.
+'
+
+test_expect_failure '--short with conflicts fixed from a merge' '
+	git commit --short
+'
With "test_expect_failure", you are saying that "--short" _should_
exit with 0 but currently it does not.  An untold expectation is
that even with the breakage with the exit code, the command still
honors the (implicit) --dry-run correctly and does not create a
new commit.

That was actually tested in the original.  By &&-chaining like this

	git commit --dry-run &&
	git commit -m "conflicts fixed from merge."

we would have noticed if a newly introduced bug caused the first
step "commit --dry-run" to return non-zero status (because then the
step would fail), or if it stopped being dry-run and made a commit
(because then the next step would fail with "nothing to commit").

But by splitting these into separate tests, the patch makes such a
potential failure with "git commit --short" break the later steps.

Not very nice.

It may be a better change to just do in the original one

	git add test-file &&
	git commit --dry-run &&
+	git commit --short &&
+	git commit --long &&
+	git commit --porcelain &&
	git commit -m "conflicts fixed from merge."

without adding these new and separate tests, and then mark that one
to expect a failure (because it would pass up to the --dry-run
commit, but the --short commit would fail) at this step, perhaps?
+test_expect_failure '--porcelain with conflicts fixed from a merge' '
+	git commit --porcelain
+'
+
+test_expect_success '--long with conflicts fixed from a merge' '
+	git commit --long
+'
+
+test_expect_success '--message with conflicts fixed from a merge' '
+	git commit --message "conflicts fixed from merge."
 '
 
 test_done
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