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[PATCH 1/2] add-patch: fix inverted return code of repo_read_index()

From
Jeff King <peff@peff.net>
Date
Sep 7, 2020, 08:08 UTC
Message-ID
<20200907080853.GA1263923@coredump.intra.peff.net>
In-Reply-To
<20200907080632.GA1261825@coredump.intra.peff.net>

After applying hunks to a file with "add -p", the C patch_update_file() function tries to refresh the index (just like the perl version does). We can only refresh the index if we're able to read it in, so we first check the return value of repo_read_index(). But unlike many functions, where "0" is success, that function is documented to return the number of entries in the index. Hence we should be checking for success with a non-negative return value.

Neither the tests nor any users seem to have noticed this, probably due to a combination of:

  - this affects only the C version, which is not yet the default
  - following it up with any porcelain command like "git diff" or "git
    commit" would refresh the index automatically.

But you can see the problem by running the plumbing "git diff-files" immediately after "add -p" stages all hunks. Running the new test with GIT_TEST_ADD_I_USE_BUILTIN=1 fails without the matching code change.

Signed-off-by: Jeff King <peff@peff.net>
---
 add-patch.c                | 2 +-
 t/t3701-add-interactive.sh | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/add-patch.c b/add-patch.c
index 457b8c550e..9544437247 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -1641,7 +1641,7 @@ static int patch_update_file(struct add_p_state *s,
 					 NULL, 0, NULL, 0))
 				error(_("'git apply' failed"));
 		}
-		if (!repo_read_index(s->s.r))
+		if (repo_read_index(s->s.r) >= 0)
 			repo_refresh_and_write_index(s->s.r, REFRESH_QUIET, 0,
 						     1, NULL, NULL, NULL);
 	}
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index fb73a847cb..67d1c36cef 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -569,6 +569,13 @@ test_expect_success 'patch mode ignores unmerged entries' '
 	diff_cmp expected diff
 '
 
+test_expect_success 'index is refreshed after applying patch' '
+	git reset --hard &&
+	echo content >test &&
+	printf y | git add -p &&
+	git diff-files --exit-code
+'
+
 test_expect_success 'diffs can be colorized' '
 	git reset --hard &&
 
-- 
2.28.0.889.g64d3ad7607
Previous: Jeff KingNext: Jeff King
Message 2 of 7 in “some minor add--interactive fixes”
  1. 0/2 some minor add--interactive fixesJeff King, Sep 7, 2020
  2. 1/2 add-patch: fix inverted return code of repo_read_index()Jeff King, Sep 7, 2020
  3. 2/2 add--interactive.perl: specify --no-color explicitlyJeff King, Sep 7, 2020
  4. Jeff KingSep 7, 2020
  5. Junio C HamanoSep 8, 2020
  6. Johannes SchindelinSep 8, 2020
  7. Jeff KingSep 9, 2020

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