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authorJeff King <peff@peff.net>2014-08-12 00:34:53 -0400
committerJunio C Hamano <gitster@pobox.com>2014-08-12 12:17:19 -0700
commitf7f91086a376ba53f8270ea80b7bbbd8274c3c2d (patch)
tree37490af7d286faf5b7e5c1d7c0f8e3f05f24e456
parent967f8c918465312cc6cc1bcbcfacafcf95152bd8 (diff)
downloadgit-f7f91086a376ba53f8270ea80b7bbbd8274c3c2d.tar.gz
pack-objects: turn off bitmaps when we see --shallow linesjk/pack-shallow-always-without-bitmap
Reachability bitmaps do not work with shallow operations, because they cache a view of the object reachability that represents the true objects. Whereas a shallow repository (or a shallow operation in a repository) is inherently cutting off the object graph with a graft. We explicitly disallow the use of bitmaps in shallow repositories by checking is_repository_shallow(), and we should continue to do that. However, we also want to disallow bitmaps when we are serving a fetch to a shallow client, since we momentarily take on their grafted view of the world. It used to be enough to call is_repository_shallow at the start of pack-objects. Upload-pack wrote the other side's shallow state to a temporary file and pointed the whole pack-objects process at this state with "git --shallow-file", and from the perspective of pack-objects, we really were in a shallow repo. But since b790e0f (upload-pack: send shallow info over stdin to pack-objects, 2014-03-11), we do it differently: we send --shallow lines to pack-objects over stdin, and it registers them itself. This means that our is_repository_shallow check is way too early (we have not been told about the shallowness yet), and that it is insufficient (calling is_repository_shallow is not enough, as the shallow grafts we register do not change its return value). Instead, we can just turn off bitmaps explicitly when we see these lines. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--builtin/pack-objects.c1
-rwxr-xr-xt/t5311-pack-bitmaps-shallow.sh39
2 files changed, 40 insertions, 0 deletions
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index de36c60ca1..2c60ddf4a8 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -2498,6 +2498,7 @@ static void get_object_list(int ac, const char **av)
if (get_sha1_hex(line + 10, sha1))
die("not an SHA-1 '%s'", line + 10);
register_shallow(sha1);
+ use_bitmap_index = 0;
continue;
}
die("not a rev '%s'", line);
diff --git a/t/t5311-pack-bitmaps-shallow.sh b/t/t5311-pack-bitmaps-shallow.sh
new file mode 100755
index 0000000000..872a95df33
--- /dev/null
+++ b/t/t5311-pack-bitmaps-shallow.sh
@@ -0,0 +1,39 @@
+#!/bin/sh
+
+test_description='check bitmap operation with shallow repositories'
+. ./test-lib.sh
+
+# We want to create a situation where the shallow, grafted
+# view of reachability does not match reality in a way that
+# might cause us to send insufficient objects.
+#
+# We do this with a history that repeats a state, like:
+#
+# A -- B -- C
+# file=1 file=2 file=1
+#
+# and then create a shallow clone to the second commit, B.
+# In a non-shallow clone, that would mean we already have
+# the tree for A. But in a shallow one, we've grafted away
+# A, and fetching A to B requires that the other side send
+# us the tree for file=1.
+test_expect_success 'setup shallow repo' '
+ echo 1 >file &&
+ git add file &&
+ git commit -m orig &&
+ echo 2 >file &&
+ git commit -a -m update &&
+ git clone --no-local --bare --depth=1 . shallow.git &&
+ echo 1 >file &&
+ git commit -a -m repeat
+'
+
+test_expect_success 'turn on bitmaps in the parent' '
+ git repack -adb
+'
+
+test_expect_success 'shallow fetch from bitmapped repo' '
+ (cd shallow.git && git fetch)
+'
+
+test_done