diff options
authorJeff King <>2010-09-21 21:01:24 (GMT)
committerJunio C Hamano <>2010-09-24 01:32:32 (GMT)
commitd391c0ff94e1b314b0664db0e8eb5bd92934f9cb (patch)
parente22148f406a7a31a25ebda01d21d9a4646ce82ea (diff)
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 <>
2 files changed, 34 insertions, 3 deletions
diff --git a/diff.c b/diff.c
index 19b5bf6..95835d8 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;
if (!one->driver->textconv)
return NULL;
diff --git a/t/ b/t/
index 918a21a..cec6196 100755
--- a/t/
+++ b/t/
@@ -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 @@
+\ No newline at end of file
+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