Staging
v0.8.1
Revision e88aab917e0dc3e99af8fb0f3ecbef66ac3e49b6 authored by Derrick Stolee on 24 October 2019, 13:40:41 UTC, committed by Junio C Hamano on 25 October 2019, 02:19:14 UTC
While dogfooding, Johannes found a bug in the fetch.writeCommitGraph
config behavior. His example initially happened during a clone with
--recurse-submodules, we found that this happens with the first fetch
after cloning a repository that contains a submodule:

	$ git clone <url> test
	$ cd test
	$ git -c fetch.writeCommitGraph=true fetch origin
	Computing commit graph generation numbers: 100% (12/12), done.
	BUG: commit-graph.c:886: missing parent <hash1> for commit <hash2>
	Aborted (core dumped)

In the repo I had cloned, there were really 60 commits to scan, but
only 12 were in the list to write when calling
compute_generation_numbers(). A commit in the list expects to see a
parent, but that parent is not in the list.

A follow-up will fix the bug, but first we create a test that
demonstrates the problem. This test must be careful about an existing
commit-graph file, since GIT_TEST_COMMIT_GRAPH=1 will cause the repo we
are cloning to already have one. This then prevents the incremtnal
commit-graph write during the first 'git fetch'.

Helped-by: Jeff King <peff@peff.net>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Helped-by: Szeder Gábor <szeder.dev@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Raw File
cache-tree.h
#ifndef CACHE_TREE_H
#define CACHE_TREE_H

#include "cache.h"
#include "tree.h"
#include "tree-walk.h"

struct cache_tree;
struct cache_tree_sub {
	struct cache_tree *cache_tree;
	int count;		/* internally used by update_one() */
	int namelen;
	int used;
	char name[FLEX_ARRAY];
};

struct cache_tree {
	int entry_count; /* negative means "invalid" */
	struct object_id oid;
	int subtree_nr;
	int subtree_alloc;
	struct cache_tree_sub **down;
};

struct cache_tree *cache_tree(void);
void cache_tree_free(struct cache_tree **);
void cache_tree_invalidate_path(struct index_state *, const char *);
struct cache_tree_sub *cache_tree_sub(struct cache_tree *, const char *);

void cache_tree_write(struct strbuf *, struct cache_tree *root);
struct cache_tree *cache_tree_read(const char *buffer, unsigned long size);

int cache_tree_fully_valid(struct cache_tree *);
int cache_tree_update(struct index_state *, int);
void cache_tree_verify(struct repository *, struct index_state *);

/* bitmasks to write_cache_as_tree flags */
#define WRITE_TREE_MISSING_OK 1
#define WRITE_TREE_IGNORE_CACHE_TREE 2
#define WRITE_TREE_DRY_RUN 4
#define WRITE_TREE_SILENT 8
#define WRITE_TREE_REPAIR 16

/* error return codes */
#define WRITE_TREE_UNREADABLE_INDEX (-1)
#define WRITE_TREE_UNMERGED_INDEX (-2)
#define WRITE_TREE_PREFIX_ERROR (-3)

int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix);
void prime_cache_tree(struct repository *, struct index_state *, struct tree *);

int cache_tree_matches_traversal(struct cache_tree *, struct name_entry *ent, struct traverse_info *info);

#ifdef USE_THE_INDEX_COMPATIBILITY_MACROS
static inline int write_cache_as_tree(struct object_id *oid, int flags, const char *prefix)
{
	return write_index_as_tree(oid, &the_index, get_index_file(), flags, prefix);
}

static inline int update_main_cache_tree(int flags)
{
	if (!the_index.cache_tree)
		the_index.cache_tree = cache_tree();
	return cache_tree_update(&the_index, flags);
}
#endif

#endif
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