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Re: finding deleted file names

From
Jeff King <peff@peff.net>
Date
Jul 3, 2008, 10:36 UTC
Message-ID
<20080703103658.GA11571@sigill.intra.peff.net>
In-Reply-To
<93c3eada0807021701m13b7adddv51537f4cf9d52533@mail.gmail.com>
On Thu, Jul 03, 2008 at 09:31:55AM +0930, Geoff Russell wrote:
Show 7 quoted lines
> git diff --diff-filter=D --name-only HEAD@{'7 days ago'}
> 
> finds files deleted during the last 7 days, but if my repository is
> only 6 days old I get a
> fatal error.
> 
> fatal: bad object HEAD@{7 days ago}

This should issue a warning, but use the oldest reflog entry. However, there is a slight problem with that. See below for details.

Shawn, does this seem sane to you?

-- >8 -- avoid null SHA1 in oldest reflog

When the user specifies a ref by a reflog entry older than one we have (e.g., "HEAD@{20 years ago"}), we issue a warning and give them the "from" value of the oldest reflog entry. That is, we say "we don't know what happened before this entry, but before this we know we had some particular SHA1".

However, the oldest reflog entry is often a creation event such as clone or branch creation. In this case, the entry claims that the ref went from "00000..." (the null sha1) to the new value, and the reflog lookup returns the null sha1.

While this is technically correct (the entry tells us that the ref didn't exist at the specified time) it is not terribly useful to the end user. What they probably want instead is "the oldest useful sha1 that this ref ever had". This patch changes the behavior such that if the oldest reflog entry would return the null sha1, it instead returns the first actual value the ref ever had.

We never discovered this problem in the test scripts because we created "fake" reflogs that had only a specified segment of history. This patch updates the tests with a creation event at the beginning of history.

Signed-off-by: Jeff King <peff@peff.net>
---
 refs.c                |    4 ++++
 t/t1400-update-ref.sh |    9 ++++++++-
 2 files changed, 12 insertions(+), 1 deletions(-)
diff --git a/refs.c b/refs.c
index 9e8e858..6c6e9e5 100644
--- a/refs.c
+++ b/refs.c
@@ -1412,6 +1412,10 @@ int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *
 	tz = strtoul(tz_c, NULL, 10);
 	if (get_sha1_hex(logdata, sha1))
 		die("Log %s is corrupt.", logfile);
+	if (is_null_sha1(sha1)) {
+		if (get_sha1_hex(logdata + 41, sha1))
+			die("Log %s is corrupt.", logfile);
+	}
 	if (msg)
 		*msg = ref_msg(logdata, logend);
 	munmap(log_mapped, mapsz);
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index f387d46..ca99d37 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -155,7 +155,8 @@ rm -f .git/$m .git/logs/$m expect
 
 git update-ref $m $D
 cat >.git/logs/$m <<EOF
-$C $A $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150320 -0500
+0000000000000000000000000000000000000000 $C $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150320 -0500
+$C $A $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150350 -0500
 $A $B $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150380 -0500
 $F $Z $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150680 -0500
 $Z $E $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150980 -0500
@@ -186,6 +187,12 @@ test_expect_success \
 	'Query "master@{May 26 2005 23:32:00}" (exactly history start)' \
 	'rm -f o e
 	 git rev-parse --verify "master@{May 26 2005 23:32:00}" >o 2>e &&
+	 test '"$C"' = $(cat o) &&
+	 test "" = "$(cat e)"'
+test_expect_success \
+	'Query "master@{May 26 2005 23:32:30}" (first non-creation change)' \
+	'rm -f o e
+	 git rev-parse --verify "master@{May 26 2005 23:32:30}" >o 2>e &&
 	 test '"$A"' = $(cat o) &&
 	 test "" = "$(cat e)"'
 test_expect_success \
-- 
1.5.6.1.282.g8aee2.dirty
Previous: Jakub NarebskiNext: Junio C Hamano
Message 12 of 16 in “finding deleted file names”
  1. Geoff RussellJul 3, 2008
  2. Mikael MagnussonJul 3, 2008
  3. Geoff RussellJul 3, 2008
  4. Mikael MagnussonJul 3, 2008
  5. Jeff KingJul 3, 2008
  6. Geoff RussellJul 4, 2008
  7. Junio C HamanoJul 4, 2008
  8. Geoff RussellJul 6, 2008
  9. Junio C HamanoJul 6, 2008
  10. Geoff RussellJul 7, 2008
  11. Jakub NarebskiJul 3, 2008
  12. Jeff KingJul 3, 2008
  13. Junio C HamanoJul 3, 2008
  14. Jeff KingJul 3, 2008
  15. Shawn O. PearceJul 3, 2008
  16. Johannes SchindelinJul 3, 2008

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