Re: [PATCH v0] sha1_name: grok <revision>:./<relative-path>

From

Jeff King <peff@peff.net>

Date

Dec 19, 2007, 15:05 UTC

Message-ID

<20071219150510.GB13942@coredump.intra.peff.net>

In-Reply-To

<Pine.LNX.4.64.0712191334460.23902@racer.site>

On Wed, Dec 19, 2007 at 01:40:27PM +0000, Johannes Schindelin wrote:

> When you are in a deeply-nested directory structure, and just want
> to reference a blob in a past revision, it can be pretty slow to
> type out "HEAD~29:/bla/blub/.../that-file".
> 
> This patch makes "HEAD~29:./that-file" substitute the current prefix
> for "./".  If there is not working directory, the prefix is empty.
> 
> Note that this patch does not handle "../", and neither do I plan to.

diff --git a/tree-walk.c b/tree-walk.c
index 8d4b673..fc54354 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -191,6 +191,7 @@ int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned ch
 	unsigned long size;
 	struct tree_desc t;
 	unsigned char root[20];
+	const char *prefix;
 
 	tree = read_object_with_reference(tree_sha1, tree_type, &size, root);
 	if (!tree)
@@ -202,7 +203,11 @@ int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned ch
 	}
 
 	init_tree_desc(&t, tree, size);
-	retval = find_tree_entry(&t, name, sha1, mode);
+	if (!prefixcmp(name, "./") && (prefix = get_current_prefix()))
+		retval = find_tree_entry(&t, mkpath("%s%s", prefix, name + 2),
+				sha1, mode);
+	else
+		retval = find_tree_entry(&t, name, sha1, mode);
 	free(tree);
 	return retval;
 }


This means that the directory '.' becomes a token replacement for "my
current path" in tree paths. So if you are in "foo/bar", and you are
looking at a distance commit where the same content was in
"baz/foo/bar", you can do:

  git show distant:baz/./file

This is probably insane because:
  - this is a fairly unlikely use case
  - get_tree_entry gets called in a lot of places, and I have no idea if
    there will be some crazy fallouts.

So it is probably not worth pursuing, but maybe somebody else can think
of a good use.

-Peff