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 <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/diff.c b/diff.c
index 19b5bf6..95835d8 100644
--- a/diff.c
+++ b/diff.c
@@ -1764,8 +1764,14 @@
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 @@
{
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;
