From d391c0ff94e1b314b0664db0e8eb5bd92934f9cb Mon Sep 17 00:00:00 2001 From: Jeff King Date: Tue, 21 Sep 2010 17:01:24 -0400 Subject: [PATCH] diff: don't use pathname-based diff drivers for symlinks When we're diffing symlinks, we consider the contents to be the pathname that the symlink points to. When a user sets up a userdiff driver like "*.pdf diff=pdf", their "diff.pdf.*" config generally tells us what to do with the content of pdf files. With the current code, we will actually process a symlink like "link.pdf" using a configured pdf driver, meaning we are using contents which consist of a pathname with configuration that is expecting contents that consist of an actual pdf file. The most noticeable example of this would have been textconv; however, it was already protected in its own textconv-specific code path. We can still see the breakage with something like "diff.*.binary", though. You could also see it with diff.*.funcname, though it is a bit harder to trigger accidentally there. This patch adds a check for S_ISREG lower in the callstack than the textconv-specific check, which should block use of any userdiff config for non-regular files. We can drop the check in the textconv code, which is now redundant. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- diff.c | 11 ++++++++--- t/t4011-diff-symlink.sh | 26 ++++++++++++++++++++++++++ 2 files changed, 34 insertions(+), 3 deletions(-) diff --git a/diff.c b/diff.c index 19b5bf63ed..95835d875e 100644 --- a/diff.c +++ b/diff.c @@ -1764,8 +1764,14 @@ static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two, char *pre static void diff_filespec_load_driver(struct diff_filespec *one) { - if (!one->driver) + /* Use already-loaded driver */ + if (one->driver) + return; + + if (S_ISREG(one->mode)) one->driver = userdiff_find_by_path(one->path); + + /* Fallback to default settings */ if (!one->driver) one->driver = userdiff_find_by_name("default"); } @@ -1813,8 +1819,7 @@ struct userdiff_driver *get_textconv(struct diff_filespec *one) { if (!DIFF_FILE_VALID(one)) return NULL; - if (!S_ISREG(one->mode)) - return NULL; + diff_filespec_load_driver(one); if (!one->driver->textconv) return NULL; diff --git a/t/t4011-diff-symlink.sh b/t/t4011-diff-symlink.sh index 918a21a2f4..cec6196685 100755 --- a/t/t4011-diff-symlink.sh +++ b/t/t4011-diff-symlink.sh @@ -94,4 +94,30 @@ test_expect_success \ test_must_fail git diff --no-index pinky brain > output 2> output.err && grep narf output && ! grep error output.err' + +test_expect_success SYMLINKS 'setup symlinks with attributes' ' + echo "*.bin diff=bin" >>.gitattributes && + echo content >file.bin && + ln -s file.bin link.bin && + git add -N file.bin link.bin +' + +cat >expect <<'EOF' +diff --git a/file.bin b/file.bin +index e69de29..d95f3ad 100644 +Binary files a/file.bin and b/file.bin differ +diff --git a/link.bin b/link.bin +index e69de29..dce41ec 120000 +--- a/link.bin ++++ b/link.bin +@@ -0,0 +1 @@ ++file.bin +\ No newline at end of file +EOF +test_expect_success SYMLINKS 'symlinks do not respect userdiff config by path' ' + git config diff.bin.binary true && + git diff file.bin link.bin >actual && + test_cmp expect actual +' + test_done