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git/commit.h
Thomas Rast 53d00b39ce log: use true parents for diff even when rewriting
When using pathspec filtering in combination with diff-based log
output, parent simplification happens before the diff is computed.
The diff is therefore against the *simplified* parents.

This works okay, arguably by accident, in the normal case:
simplification reduces to one parent as long as the commit is TREESAME
to it.  So the simplified parent of any given commit must have the
same tree contents on the filtered paths as its true (unfiltered)
parent.

However, --full-diff breaks this guarantee, and indeed gives pretty
spectacular results when comparing the output of

  git log --graph --stat ...
  git log --graph --full-diff --stat ...

(--graph internally kicks in parent simplification, much like
--parents).

To fix it, store a copy of the parent list before simplification (in a
slab) whenever --full-diff is in effect.  Then use the stored parents
instead of the simplified ones in the commit display code paths.  The
latter do not actually check for --full-diff to avoid duplicated code;
they just grab the original parents if save_parents() has not been
called for this revision walk.

For ordinary commits it should be obvious that this is the right thing
to do.

Merge commits are a bit subtle.  Observe that with default
simplification, merge simplification is an all-or-nothing decision:
either the merge is TREESAME to one parent and disappears, or it is
different from all parents and the parent list remains intact.
Redundant parents are not pruned, so the existing code also shows them
as a merge.

So if we do show a merge commit, the parent list just consists of the
rewrite result on each parent.  Running, e.g., --cc on this in
--full-diff mode is not very useful: if any commits were skipped, some
hunks will disagree with all sides of the merge (with one side,
because commits were skipped; with the others, because they didn't
have those changes in the first place).  This triggers --cc showing
these hunks spuriously.

Therefore I believe that even for merge commits it is better to show
the diffs wrt. the original parents.

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Thomas Rast <trast@inf.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-08-01 10:25:48 -07:00

276 lines
9.0 KiB
C

#ifndef COMMIT_H
#define COMMIT_H
#include "object.h"
#include "tree.h"
#include "strbuf.h"
#include "decorate.h"
#include "gpg-interface.h"
#include "string-list.h"
struct commit_list {
struct commit *item;
struct commit_list *next;
};
struct commit {
struct object object;
void *util;
unsigned int index;
unsigned long date;
struct commit_list *parents;
struct tree *tree;
char *buffer;
};
extern int save_commit_buffer;
extern const char *commit_type;
/* While we can decorate any object with a name, it's only used for commits.. */
extern struct decoration name_decoration;
struct name_decoration {
struct name_decoration *next;
int type;
char name[1];
};
struct commit *lookup_commit(const unsigned char *sha1);
struct commit *lookup_commit_reference(const unsigned char *sha1);
struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
int quiet);
struct commit *lookup_commit_reference_by_name(const char *name);
/*
* Look up object named by "sha1", dereference tag as necessary,
* get a commit and return it. If "sha1" does not dereference to
* a commit, use ref_name to report an error and die.
*/
struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name);
int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size);
int parse_commit(struct commit *item);
/* Find beginning and length of commit subject. */
int find_commit_subject(const char *commit_buffer, const char **subject);
struct commit_list *commit_list_insert(struct commit *item,
struct commit_list **list);
struct commit_list **commit_list_append(struct commit *commit,
struct commit_list **next);
unsigned commit_list_count(const struct commit_list *l);
struct commit_list *commit_list_insert_by_date(struct commit *item,
struct commit_list **list);
void commit_list_sort_by_date(struct commit_list **list);
/* Shallow copy of the input list */
struct commit_list *copy_commit_list(struct commit_list *list);
void free_commit_list(struct commit_list *list);
/* Commit formats */
enum cmit_fmt {
CMIT_FMT_RAW,
CMIT_FMT_MEDIUM,
CMIT_FMT_DEFAULT = CMIT_FMT_MEDIUM,
CMIT_FMT_SHORT,
CMIT_FMT_FULL,
CMIT_FMT_FULLER,
CMIT_FMT_ONELINE,
CMIT_FMT_EMAIL,
CMIT_FMT_USERFORMAT,
CMIT_FMT_UNSPECIFIED
};
struct pretty_print_context {
/*
* Callers should tweak these to change the behavior of pp_* functions.
*/
enum cmit_fmt fmt;
int abbrev;
const char *subject;
const char *after_subject;
int preserve_subject;
enum date_mode date_mode;
unsigned date_mode_explicit:1;
int need_8bit_cte;
char *notes_message;
struct reflog_walk_info *reflog_info;
const char *output_encoding;
struct string_list *mailmap;
int color;
struct ident_split *from_ident;
/*
* Fields below here are manipulated internally by pp_* functions and
* should not be counted on by callers.
*/
/* Manipulated by the pp_* functions internally. */
struct string_list in_body_headers;
};
struct userformat_want {
unsigned notes:1;
};
extern int has_non_ascii(const char *text);
struct rev_info; /* in revision.h, it circularly uses enum cmit_fmt */
extern char *logmsg_reencode(const struct commit *commit,
char **commit_encoding,
const char *output_encoding);
extern void logmsg_free(char *msg, const struct commit *commit);
extern void get_commit_format(const char *arg, struct rev_info *);
extern const char *format_subject(struct strbuf *sb, const char *msg,
const char *line_separator);
extern void userformat_find_requirements(const char *fmt, struct userformat_want *w);
extern void format_commit_message(const struct commit *commit,
const char *format, struct strbuf *sb,
const struct pretty_print_context *context);
extern void pretty_print_commit(struct pretty_print_context *pp,
const struct commit *commit,
struct strbuf *sb);
extern void pp_commit_easy(enum cmit_fmt fmt, const struct commit *commit,
struct strbuf *sb);
void pp_user_info(struct pretty_print_context *pp,
const char *what, struct strbuf *sb,
const char *line, const char *encoding);
void pp_title_line(struct pretty_print_context *pp,
const char **msg_p,
struct strbuf *sb,
const char *encoding,
int need_8bit_cte);
void pp_remainder(struct pretty_print_context *pp,
const char **msg_p,
struct strbuf *sb,
int indent);
/** Removes the first commit from a list sorted by date, and adds all
* of its parents.
**/
struct commit *pop_most_recent_commit(struct commit_list **list,
unsigned int mark);
struct commit *pop_commit(struct commit_list **stack);
void clear_commit_marks(struct commit *commit, unsigned int mark);
void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark);
void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark);
enum rev_sort_order {
REV_SORT_IN_GRAPH_ORDER = 0,
REV_SORT_BY_COMMIT_DATE,
REV_SORT_BY_AUTHOR_DATE
};
/*
* Performs an in-place topological sort of list supplied.
*
* invariant of resulting list is:
* a reachable from b => ord(b) < ord(a)
* sort_order further specifies:
* REV_SORT_IN_GRAPH_ORDER: try to show a commit on a single-parent
* chain together.
* REV_SORT_BY_COMMIT_DATE: show eligible commits in committer-date order.
*/
void sort_in_topological_order(struct commit_list **, enum rev_sort_order);
struct commit_graft {
unsigned char sha1[20];
int nr_parent; /* < 0 if shallow commit */
unsigned char parent[FLEX_ARRAY][20]; /* more */
};
typedef int (*each_commit_graft_fn)(const struct commit_graft *, void *);
struct commit_graft *read_graft_line(char *buf, int len);
int register_commit_graft(struct commit_graft *, int);
struct commit_graft *lookup_commit_graft(const unsigned char *sha1);
extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2, int cleanup);
extern struct commit_list *get_merge_bases_many(struct commit *one, int n, struct commit **twos, int cleanup);
extern struct commit_list *get_octopus_merge_bases(struct commit_list *in);
/* largest positive number a signed 32-bit integer can contain */
#define INFINITE_DEPTH 0x7fffffff
extern int register_shallow(const unsigned char *sha1);
extern int unregister_shallow(const unsigned char *sha1);
extern int for_each_commit_graft(each_commit_graft_fn, void *);
extern int is_repository_shallow(void);
extern struct commit_list *get_shallow_commits(struct object_array *heads,
int depth, int shallow_flag, int not_shallow_flag);
extern void check_shallow_file_for_update(void);
extern void set_alternate_shallow_file(const char *path);
int is_descendant_of(struct commit *, struct commit_list *);
int in_merge_bases(struct commit *, struct commit *);
int in_merge_bases_many(struct commit *, int, struct commit **);
extern int interactive_add(int argc, const char **argv, const char *prefix, int patch);
extern int run_add_interactive(const char *revision, const char *patch_mode,
const char **pathspec);
static inline int single_parent(struct commit *commit)
{
return commit->parents && !commit->parents->next;
}
struct commit_list *reduce_heads(struct commit_list *heads);
struct commit_extra_header {
struct commit_extra_header *next;
char *key;
char *value;
size_t len;
};
extern void append_merge_tag_headers(struct commit_list *parents,
struct commit_extra_header ***tail);
extern int commit_tree(const struct strbuf *msg, unsigned char *tree,
struct commit_list *parents, unsigned char *ret,
const char *author, const char *sign_commit);
extern int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
struct commit_list *parents, unsigned char *ret,
const char *author, const char *sign_commit,
struct commit_extra_header *);
extern struct commit_extra_header *read_commit_extra_headers(struct commit *, const char **);
extern void free_commit_extra_headers(struct commit_extra_header *extra);
struct merge_remote_desc {
struct object *obj; /* the named object, could be a tag */
const char *name;
};
#define merge_remote_util(commit) ((struct merge_remote_desc *)((commit)->util))
/*
* Given "name" from the command line to merge, find the commit object
* and return it, while storing merge_remote_desc in its ->util field,
* to allow callers to tell if we are told to merge a tag.
*/
struct commit *get_merge_parent(const char *name);
extern int parse_signed_commit(const unsigned char *sha1,
struct strbuf *message, struct strbuf *signature);
extern void print_commit_list(struct commit_list *list,
const char *format_cur,
const char *format_last);
/*
* Check the signature of the given commit. The result of the check is stored
* in sig->check_result, 'G' for a good signature, 'U' for a good signature
* from an untrusted signer, 'B' for a bad signature and 'N' for no signature
* at all. This may allocate memory for sig->gpg_output, sig->gpg_status,
* sig->signer and sig->key.
*/
extern void check_commit_signature(const struct commit* commit, struct signature_check *sigc);
int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused);
#endif /* COMMIT_H */