When we diff a blob against a working tree file like:
git diff HEAD:Makefile Makefile
we always use the working tree filename for both sides of
the diff. In most cases that's fine, as the two would be the
same anyway, as above. And until recently, we used the
"name" for the blob, not the path, which would have the
messy "HEAD:" on the beginning.
But when they don't match, like:
git diff HEAD:old_path new_path
it makes sense to show both names.
This patch uses the blob's path field if it's available, and
otherwise falls back to using the filename (in preference to
the blob's name, which is likely to be garbage like a raw
sha1).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There's a subtle distinction between "name" and "path" for a
blob that we resolve: the name is what the user told us on
the command line, and the path is what we traversed when
finding the blob within a tree (if we did so).
When we diff blobs directly, we use "name", but "path" is
more likely to be useful to the user (it will find the
correct .gitattributes, and give them a saner diff header).
We still have to fall back to using the name for some cases
(i.e., any blob reference that isn't of the form tree:path).
That's the best we can do in such a case.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "a..b" revision syntax was designed to handle commits,
so it doesn't bother to record any mode we find while
traversing a "tree:path" endpoint. These days "git diff" can
diff blobs using either "a:path..b:path" (with dots) or
"a:path b:path" (without), but the two behave
inconsistently, as the with-dots version fails to notice the
mode.
Let's teach the dot-dot range parser to record modes; it
doesn't cost us anything, and it makes this case work.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The git-diff command can directly compare two blobs (or a
blob and a file), but we don't test this at all. Let's add
some basic tests that reveal a few problems.
There are basically four interesting inputs:
1. sha1 against sha1 (where diff has no information beyond
the contents)
2. tree:path against tree:path (where it can get
information via get_sha1_with_context)
3. Same as (2), but using the ".." range syntax
4. tree:path against a filename
And beyond generating a sane diff, we care about a few
little bits: which paths they show in the diff header, and
whether they correctly pick up a mode change.
They should all be able to show a mode except for (1),
though note that case (3) is currently broken.
For the headers, we would ideally show the path within the
tree if we have it, making:
git diff a:path b:path
look the same as:
git diff a b -- path
We can't always do that (e.g., in the direct sha1/sha1 diff,
we have no path to show), in which case we should fall back
to the name that resolved to the blob (which is nonsense
from the repository's perspective, but is the best we can
do).
Aside from the fallback case in (1), none of the cases get
this right. Cases (2) and (3) always show the full
tree:path, even though we should be able to know just the
"path" portion.
Case (4) picks up the filename path, but assigns it to
_both_ sides of the diff. So this works for:
git diff tree:path path
but not for:
git diff tree:other_path path
The appropriate tests are marked to expect failure.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
