Re: [PATCH 1/2] pack-refs: write peeled entry for non-tags
flat view
From: Michael Haggerty <hidden>
Date: 2016-06-15 22:56:25
Looks good aside from a couple of minor points mentioned below. On 03/16/2013 10:01 AM, Jeff King wrote:
When we pack an annotated tag ref, we write not only the sha1 of the tag object along with the ref, but also the sha1 obtained by peeling the tag. This lets readers of the pack-refs file know the peeled value without having to actually load the object, speeding up upload-pack's ref advertisement. The writer marks a packed-refs file with peeled refs using the "peeled" trait at the top of the file. When the reader sees this trait, it knows that each ref is either followed by its peeled value, or it is not an annotated tag. However, there is a mismatch between the assumptions of the reader and writer. The writer will only peel refs under refs/tags, but the reader does not know this; it will assume a ref without a peeled value must not be a tag object. Thus an annotated tag object placed outside of the refs/tags hierarchy will not have its peeled value printed by upload-pack. The simplest way to fix this is to start writing peel values for all refs. This matches what the reader expects for both new and old versions of git. Signed-off-by: Jeff King <redacted>
I like your explanation of the problem.
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--- pack-refs.c | 16 ++++++++-------- t/t3211-peel-ref.sh | 42 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 50 insertions(+), 8 deletions(-) create mode 100755 t/t3211-peel-ref.shdiff --git a/pack-refs.c b/pack-refs.c index f09a054..10832d7 100644 --- a/pack-refs.c +++ b/pack-refs.c@@ -27,6 +27,7 @@ static int handle_one_ref(const char *path, const unsigned char *sha1, int flags, void *cb_data) { struct pack_refs_cb_data *cb = cb_data; + struct object *o; int is_tag_ref; /* Do not pack the symbolic refs */@@ -39,14 +40,13 @@ static int handle_one_ref(const char *path, const unsigned char *sha1, return 0; fprintf(cb->refs_file, "%s %s\n", sha1_to_hex(sha1), path); - if (is_tag_ref) { - struct object *o = parse_object(sha1); - if (o->type == OBJ_TAG) { - o = deref_tag(o, path, 0); - if (o) - fprintf(cb->refs_file, "^%s\n", - sha1_to_hex(o->sha1)); - } + + o = parse_object(sha1); + if (o->type == OBJ_TAG) {
You suggested that I add a test (o != NULL) at the equivalent place in my code (which was derived from this code). Granted, my code was explicitly intending to pass invalid SHA1 values to parse_object(). But wouldn't it be a good defensive step to add the same check here?
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+ o = deref_tag(o, path, 0); + if (o) + fprintf(cb->refs_file, "^%s\n", + sha1_to_hex(o->sha1)); } if ((cb->flags & PACK_REFS_PRUNE) && !do_not_prune(flags)) {diff --git a/t/t3211-peel-ref.sh b/t/t3211-peel-ref.sh new file mode 100755 index 0000000..dd5b48b --- /dev/null +++ b/t/t3211-peel-ref.sh@@ -0,0 +1,42 @@ +#!/bin/sh + +test_description='tests for the peel_ref optimization of packed-refs' +. ./test-lib.sh + +test_expect_success 'create annotated tag in refs/tags' ' + test_commit base && + git tag -m annotated foo +' + +test_expect_success 'create annotated tag outside of refs/tags' ' + git update-ref refs/outside/foo refs/tags/foo +' + +# This matches show-ref's output +print_ref() { + echo "`git rev-parse "$1"` $1" +} +
CodingGuidelines prefers $() over ``.
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+test_expect_success 'set up expected show-ref output' ' + { + print_ref "refs/heads/master" && + print_ref "refs/outside/foo" && + print_ref "refs/outside/foo^{}" && + print_ref "refs/tags/base" && + print_ref "refs/tags/foo" && + print_ref "refs/tags/foo^{}" + } >expect +' + +test_expect_success 'refs are peeled outside of refs/tags (loose)' ' + git show-ref -d >actual && + test_cmp expect actual +' + +test_expect_success 'refs are peeled outside of refs/tags (packed)' ' + git pack-refs --all && + git show-ref -d >actual && + test_cmp expect actual +' + +test_done
-- Michael Haggerty mhagger@alum.mit.edu http://softwareswirl.blogspot.com/