Re: 'setup_work_tree()' considered harmful

[Linus Torvalds <torvalds@linux-foundation.org>]

On Mon, 16 Jun 2008, Linus Torvalds wrote:
> 
> After that, I fixed "write_loose_object()" to not unnecessarily try to 
> open a git object file, because every single caller has already done a 
> "has_sha1_file(sha1)" or "has_loose_object(sha1)" check before calling 
> that function, so trying to open it again is just pointless.

In case anybody cares, the obvious diff for this part is appended. The 
FIXME! was wrong anyway - any collision detection needs to be done by the 
callers when they do the "do we already have this object". Doing it in 
write_loose_object() is too late (not to mention the wrong place to try to 
do so anyway - not all callers generate new objects: some callers just 
turn a packed object into a loose one).

			Linus

---
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon, 16 Jun 2008 17:17:10 -0700
Subject: [PATCH] write_loose_object: don't bother trying to read an old object

Before even calling this, all callers have done a "has_sha1_file(sha1)"
or "has_loose_object(sha1)" check, so there is no point in doing a
second check.

If something races with us on object creation, we handle that in the
final link() that moves it to the right place.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 sha1_file.c |   14 --------------
 1 files changed, 0 insertions(+), 14 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index f9ec069..4255099 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2160,20 +2160,6 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
 	static char tmpfile[PATH_MAX];
 
 	filename = sha1_file_name(sha1);
-	fd = open(filename, O_RDONLY);
-	if (fd >= 0) {
-		/*
-		 * FIXME!!! We might do collision checking here, but we'd
-		 * need to uncompress the old file and check it. Later.
-		 */
-		close(fd);
-		return 0;
-	}
-
-	if (errno != ENOENT) {
-		return error("sha1 file %s: %s\n", filename, strerror(errno));
-	}
-
 	fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
 	if (fd < 0) {
 		if (errno == EPERM)
-- 
1.5.6.rc3.7.g336d0.dirty