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cb99a34e23
The previous commit includes a failing test for an issue around
fetch.writeCommitGraph and fetching in a repo with a submodule. Here, we
fix that bug and set the test to "test_expect_success".
The problem arises with this set of commands when the remote repo at
<url> has a submodule. Note that --recurse-submodules is not needed to
demonstrate the bug.
$ 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)
As an initial fix, I converted the code in builtin/fetch.c that calls
write_commit_graph_reachable() to instead launch a "git commit-graph
write --reachable --split" process. That code worked, but is not how we
want the feature to work long-term.
That test did demonstrate that the issue must be something to do with
internal state of the 'git fetch' process.
The write_commit_graph() method in commit-graph.c ensures the commits we
plan to write are "closed under reachability" using close_reachable().
This method walks from the input commits, and uses the UNINTERESTING
flag to mark which commits have already been visited. This allows the
walk to take O(N) time, where N is the number of commits, instead of
O(P) time, where P is the number of paths. (The number of paths can be
exponential in the number of commits.)
However, the UNINTERESTING flag is used in lots of places in the
codebase. This flag usually means some barrier to stop a commit walk,
such as in revision-walking to compare histories. It is not often
cleared after the walk completes because the starting points of those
walks do not have the UNINTERESTING flag, and clear_commit_marks() would
stop immediately.
This is happening during a 'git fetch' call with a remote. The fetch
negotiation is comparing the remote refs with the local refs and marking
some commits as UNINTERESTING.
I tested running clear_commit_marks_many() to clear the UNINTERESTING
flag inside close_reachable(), but the tips did not have the flag, so
that did nothing.
It turns out that the calculate_changed_submodule_paths() method is at
fault. Thanks, Peff, for pointing out this detail! More specifically,
for each submodule, the collect_changed_submodules() runs a revision
walk to essentially do file-history on the list of submodules. That
revision walk marks commits UNININTERESTING if they are simplified away
by not changing the submodule.
Instead, I finally arrived on the conclusion that I should use a flag
that is not used in any other part of the code. In commit-reach.c, a
number of flags were defined for commit walk algorithms. The REACHABLE
flag seemed like it made the most sense, and it seems it was not
actually used in the file. The REACHABLE flag was used in early versions
of commit-reach.c, but was removed by 4fbcca4 (commit-reach: make
can_all_from_reach... linear, 2018-07-20).
Add the REACHABLE flag to commit-graph.c and use it instead of
UNINTERESTING in close_reachable(). This fixes the bug in manual
testing.
Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Helped-by: Jeff King <peff@peff.net>
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>
196 lines
6.3 KiB
C
196 lines
6.3 KiB
C
#ifndef OBJECT_H
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#define OBJECT_H
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#include "cache.h"
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struct buffer_slab;
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struct parsed_object_pool {
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struct object **obj_hash;
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int nr_objs, obj_hash_size;
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/* TODO: migrate alloc_states to mem-pool? */
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struct alloc_state *blob_state;
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struct alloc_state *tree_state;
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struct alloc_state *commit_state;
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struct alloc_state *tag_state;
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struct alloc_state *object_state;
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unsigned commit_count;
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/* parent substitutions from .git/info/grafts and .git/shallow */
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struct commit_graft **grafts;
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int grafts_alloc, grafts_nr;
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int is_shallow;
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struct stat_validity *shallow_stat;
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char *alternate_shallow_file;
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int commit_graft_prepared;
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struct buffer_slab *buffer_slab;
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};
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struct parsed_object_pool *parsed_object_pool_new(void);
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void parsed_object_pool_clear(struct parsed_object_pool *o);
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struct object_list {
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struct object *item;
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struct object_list *next;
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};
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struct object_array {
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unsigned int nr;
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unsigned int alloc;
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struct object_array_entry {
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struct object *item;
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/*
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* name or NULL. If non-NULL, the memory pointed to
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* is owned by this object *except* if it points at
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* object_array_slopbuf, which is a static copy of the
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* empty string.
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*/
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char *name;
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char *path;
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unsigned mode;
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} *objects;
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};
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#define OBJECT_ARRAY_INIT { 0, 0, NULL }
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/*
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* object flag allocation:
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* revision.h: 0---------10 25----28
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* fetch-pack.c: 01
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* negotiator/default.c: 2--5
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* walker.c: 0-2
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* upload-pack.c: 4 11-----14 16-----19
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* builtin/blame.c: 12-13
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* bisect.c: 16
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* bundle.c: 16
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* http-push.c: 16-----19
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* commit-graph.c: 15
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* commit-reach.c: 16-----19
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* sha1-name.c: 20
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* list-objects-filter.c: 21
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* builtin/fsck.c: 0--3
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* builtin/index-pack.c: 2021
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* builtin/pack-objects.c: 20
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* builtin/reflog.c: 10--12
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* builtin/show-branch.c: 0-------------------------------------------26
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* builtin/unpack-objects.c: 2021
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*/
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#define FLAG_BITS 29
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/*
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* The object type is stored in 3 bits.
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*/
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struct object {
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unsigned parsed : 1;
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unsigned type : TYPE_BITS;
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unsigned flags : FLAG_BITS;
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struct object_id oid;
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};
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const char *type_name(unsigned int type);
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int type_from_string_gently(const char *str, ssize_t, int gentle);
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#define type_from_string(str) type_from_string_gently(str, -1, 0)
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/*
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* Return the current number of buckets in the object hashmap.
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*/
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unsigned int get_max_object_index(void);
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/*
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* Return the object from the specified bucket in the object hashmap.
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*/
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struct object *get_indexed_object(unsigned int);
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/*
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* This can be used to see if we have heard of the object before, but
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* it can return "yes we have, and here is a half-initialised object"
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* for an object that we haven't loaded/parsed yet.
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*
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* When parsing a commit to create an in-core commit object, its
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* parents list holds commit objects that represent its parents, but
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* they are expected to be lazily initialized and do not know what
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* their trees or parents are yet. When this function returns such a
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* half-initialised objects, the caller is expected to initialize them
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* by calling parse_object() on them.
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*/
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struct object *lookup_object(struct repository *r, const struct object_id *oid);
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void *create_object(struct repository *r, const struct object_id *oid, void *obj);
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void *object_as_type(struct repository *r, struct object *obj, enum object_type type, int quiet);
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/*
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* Returns the object, having parsed it to find out what it is.
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*
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* Returns NULL if the object is missing or corrupt.
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*/
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struct object *parse_object(struct repository *r, const struct object_id *oid);
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/*
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* Like parse_object, but will die() instead of returning NULL. If the
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* "name" parameter is not NULL, it is included in the error message
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* (otherwise, the hex object ID is given).
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*/
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struct object *parse_object_or_die(const struct object_id *oid, const char *name);
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/* Given the result of read_sha1_file(), returns the object after
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* parsing it. eaten_p indicates if the object has a borrowed copy
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* of buffer and the caller should not free() it.
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*/
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struct object *parse_object_buffer(struct repository *r, const struct object_id *oid, enum object_type type, unsigned long size, void *buffer, int *eaten_p);
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/** Returns the object, with potentially excess memory allocated. **/
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struct object *lookup_unknown_object(const struct object_id *oid);
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struct object_list *object_list_insert(struct object *item,
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struct object_list **list_p);
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int object_list_contains(struct object_list *list, struct object *obj);
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/* Object array handling .. */
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void add_object_array(struct object *obj, const char *name, struct object_array *array);
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void add_object_array_with_path(struct object *obj, const char *name, struct object_array *array, unsigned mode, const char *path);
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/*
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* Returns NULL if the array is empty. Otherwise, returns the last object
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* after removing its entry from the array. Other resources associated
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* with that object are left in an unspecified state and should not be
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* examined.
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*/
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struct object *object_array_pop(struct object_array *array);
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typedef int (*object_array_each_func_t)(struct object_array_entry *, void *);
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/*
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* Apply want to each entry in array, retaining only the entries for
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* which the function returns true. Preserve the order of the entries
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* that are retained.
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*/
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void object_array_filter(struct object_array *array,
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object_array_each_func_t want, void *cb_data);
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/*
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* Remove from array all but the first entry with a given name.
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* Warning: this function uses an O(N^2) algorithm.
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*/
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void object_array_remove_duplicates(struct object_array *array);
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/*
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* Remove any objects from the array, freeing all used memory; afterwards
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* the array is ready to store more objects with add_object_array().
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*/
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void object_array_clear(struct object_array *array);
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void clear_object_flags(unsigned flags);
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/*
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* Clear the specified object flags from all in-core commit objects.
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*/
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void clear_commit_marks_all(unsigned int flags);
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#endif /* OBJECT_H */
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