git/builtin-revert.c
Robin Rosenberg d5be89d8ad git-revert: record the parent against which a revert was made
As described in Documentation/howto/revert-a-faulty-merge.txt, re-merging
from a previously reverted a merge of a side branch may need a revert of
the revert beforehand.  Record against which parent the revert was made in
the commit, so that later the user can figure out what went on.

Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-12-21 18:32:04 -08:00

460 lines
12 KiB
C

#include "cache.h"
#include "builtin.h"
#include "object.h"
#include "commit.h"
#include "tag.h"
#include "wt-status.h"
#include "run-command.h"
#include "exec_cmd.h"
#include "utf8.h"
#include "parse-options.h"
#include "cache-tree.h"
#include "diff.h"
#include "revision.h"
#include "rerere.h"
#include "merge-recursive.h"
/*
* This implements the builtins revert and cherry-pick.
*
* Copyright (c) 2007 Johannes E. Schindelin
*
* Based on git-revert.sh, which is
*
* Copyright (c) 2005 Linus Torvalds
* Copyright (c) 2005 Junio C Hamano
*/
static const char * const revert_usage[] = {
"git revert [options] <commit-ish>",
NULL
};
static const char * const cherry_pick_usage[] = {
"git cherry-pick [options] <commit-ish>",
NULL
};
static int edit, no_replay, no_commit, mainline, signoff;
static enum { REVERT, CHERRY_PICK } action;
static struct commit *commit;
static const char *me;
#define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
static void parse_args(int argc, const char **argv)
{
const char * const * usage_str =
action == REVERT ? revert_usage : cherry_pick_usage;
unsigned char sha1[20];
const char *arg;
int noop;
struct option options[] = {
OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
OPT_BOOLEAN('x', NULL, &no_replay, "append commit name when cherry-picking"),
OPT_BOOLEAN('r', NULL, &noop, "no-op (backward compatibility)"),
OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
OPT_INTEGER('m', "mainline", &mainline, "parent number"),
OPT_END(),
};
if (parse_options(argc, argv, options, usage_str, 0) != 1)
usage_with_options(usage_str, options);
arg = argv[0];
if (get_sha1(arg, sha1))
die ("Cannot find '%s'", arg);
commit = (struct commit *)parse_object(sha1);
if (!commit)
die ("Could not find %s", sha1_to_hex(sha1));
if (commit->object.type == OBJ_TAG) {
commit = (struct commit *)
deref_tag((struct object *)commit, arg, strlen(arg));
}
if (commit->object.type != OBJ_COMMIT)
die ("'%s' does not point to a commit", arg);
}
static char *get_oneline(const char *message)
{
char *result;
const char *p = message, *abbrev, *eol;
int abbrev_len, oneline_len;
if (!p)
die ("Could not read commit message of %s",
sha1_to_hex(commit->object.sha1));
while (*p && (*p != '\n' || p[1] != '\n'))
p++;
if (*p) {
p += 2;
for (eol = p + 1; *eol && *eol != '\n'; eol++)
; /* do nothing */
} else
eol = p;
abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
abbrev_len = strlen(abbrev);
oneline_len = eol - p;
result = xmalloc(abbrev_len + 5 + oneline_len);
memcpy(result, abbrev, abbrev_len);
memcpy(result + abbrev_len, "... ", 4);
memcpy(result + abbrev_len + 4, p, oneline_len);
result[abbrev_len + 4 + oneline_len] = '\0';
return result;
}
static char *get_encoding(const char *message)
{
const char *p = message, *eol;
if (!p)
die ("Could not read commit message of %s",
sha1_to_hex(commit->object.sha1));
while (*p && *p != '\n') {
for (eol = p + 1; *eol && *eol != '\n'; eol++)
; /* do nothing */
if (!prefixcmp(p, "encoding ")) {
char *result = xmalloc(eol - 8 - p);
strlcpy(result, p + 9, eol - 8 - p);
return result;
}
p = eol;
if (*p == '\n')
p++;
}
return NULL;
}
static struct lock_file msg_file;
static int msg_fd;
static void add_to_msg(const char *string)
{
int len = strlen(string);
if (write_in_full(msg_fd, string, len) < 0)
die ("Could not write to MERGE_MSG");
}
static void add_message_to_msg(const char *message)
{
const char *p = message;
while (*p && (*p != '\n' || p[1] != '\n'))
p++;
if (!*p)
add_to_msg(sha1_to_hex(commit->object.sha1));
p += 2;
add_to_msg(p);
return;
}
static void set_author_ident_env(const char *message)
{
const char *p = message;
if (!p)
die ("Could not read commit message of %s",
sha1_to_hex(commit->object.sha1));
while (*p && *p != '\n') {
const char *eol;
for (eol = p; *eol && *eol != '\n'; eol++)
; /* do nothing */
if (!prefixcmp(p, "author ")) {
char *line, *pend, *email, *timestamp;
p += 7;
line = xmemdupz(p, eol - p);
email = strchr(line, '<');
if (!email)
die ("Could not extract author email from %s",
sha1_to_hex(commit->object.sha1));
if (email == line)
pend = line;
else
for (pend = email; pend != line + 1 &&
isspace(pend[-1]); pend--);
; /* do nothing */
*pend = '\0';
email++;
timestamp = strchr(email, '>');
if (!timestamp)
die ("Could not extract author time from %s",
sha1_to_hex(commit->object.sha1));
*timestamp = '\0';
for (timestamp++; *timestamp && isspace(*timestamp);
timestamp++)
; /* do nothing */
setenv("GIT_AUTHOR_NAME", line, 1);
setenv("GIT_AUTHOR_EMAIL", email, 1);
setenv("GIT_AUTHOR_DATE", timestamp, 1);
free(line);
return;
}
p = eol;
if (*p == '\n')
p++;
}
die ("No author information found in %s",
sha1_to_hex(commit->object.sha1));
}
static char *help_msg(const unsigned char *sha1)
{
static char helpbuf[1024];
char *msg = getenv("GIT_CHERRY_PICK_HELP");
if (msg)
return msg;
strcpy(helpbuf, " After resolving the conflicts,\n"
"mark the corrected paths with 'git add <paths>' "
"or 'git rm <paths>' and commit the result.");
if (action == CHERRY_PICK) {
sprintf(helpbuf + strlen(helpbuf),
"\nWhen commiting, use the option "
"'-c %s' to retain authorship and message.",
find_unique_abbrev(sha1, DEFAULT_ABBREV));
}
return helpbuf;
}
static int index_is_dirty(void)
{
struct rev_info rev;
init_revisions(&rev, NULL);
setup_revisions(0, NULL, &rev, "HEAD");
DIFF_OPT_SET(&rev.diffopt, QUIET);
DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
run_diff_index(&rev, 1);
return !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
}
static struct tree *empty_tree(void)
{
struct tree *tree = xcalloc(1, sizeof(struct tree));
tree->object.parsed = 1;
tree->object.type = OBJ_TREE;
pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
return tree;
}
static int revert_or_cherry_pick(int argc, const char **argv)
{
unsigned char head[20];
struct commit *base, *next, *parent;
int i, index_fd, clean;
char *oneline, *reencoded_message = NULL;
const char *message, *encoding;
char *defmsg = git_pathdup("MERGE_MSG");
struct merge_options o;
struct tree *result, *next_tree, *base_tree, *head_tree;
static struct lock_file index_lock;
git_config(git_default_config, NULL);
me = action == REVERT ? "revert" : "cherry-pick";
setenv(GIT_REFLOG_ACTION, me, 0);
parse_args(argc, argv);
/* this is copied from the shell script, but it's never triggered... */
if (action == REVERT && !no_replay)
die("revert is incompatible with replay");
if (read_cache() < 0)
die("git %s: failed to read the index", me);
if (no_commit) {
/*
* We do not intend to commit immediately. We just want to
* merge the differences in, so let's compute the tree
* that represents the "current" state for merge-recursive
* to work on.
*/
if (write_cache_as_tree(head, 0, NULL))
die ("Your index file is unmerged.");
} else {
if (get_sha1("HEAD", head))
die ("You do not have a valid HEAD");
if (index_is_dirty())
die ("Dirty index: cannot %s", me);
}
discard_cache();
index_fd = hold_locked_index(&index_lock, 1);
if (!commit->parents) {
if (action == REVERT)
die ("Cannot revert a root commit");
parent = NULL;
}
else if (commit->parents->next) {
/* Reverting or cherry-picking a merge commit */
int cnt;
struct commit_list *p;
if (!mainline)
die("Commit %s is a merge but no -m option was given.",
sha1_to_hex(commit->object.sha1));
for (cnt = 1, p = commit->parents;
cnt != mainline && p;
cnt++)
p = p->next;
if (cnt != mainline || !p)
die("Commit %s does not have parent %d",
sha1_to_hex(commit->object.sha1), mainline);
parent = p->item;
} else if (0 < mainline)
die("Mainline was specified but commit %s is not a merge.",
sha1_to_hex(commit->object.sha1));
else
parent = commit->parents->item;
if (!(message = commit->buffer))
die ("Cannot get commit message for %s",
sha1_to_hex(commit->object.sha1));
if (parent && parse_commit(parent) < 0)
die("%s: cannot parse parent commit %s",
me, sha1_to_hex(parent->object.sha1));
/*
* "commit" is an existing commit. We would want to apply
* the difference it introduces since its first parent "prev"
* on top of the current HEAD if we are cherry-pick. Or the
* reverse of it if we are revert.
*/
msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
LOCK_DIE_ON_ERROR);
encoding = get_encoding(message);
if (!encoding)
encoding = "utf-8";
if (!git_commit_encoding)
git_commit_encoding = "utf-8";
if ((reencoded_message = reencode_string(message,
git_commit_encoding, encoding)))
message = reencoded_message;
oneline = get_oneline(message);
if (action == REVERT) {
char *oneline_body = strchr(oneline, ' ');
base = commit;
next = parent;
add_to_msg("Revert \"");
add_to_msg(oneline_body + 1);
add_to_msg("\"\n\nThis reverts commit ");
add_to_msg(sha1_to_hex(commit->object.sha1));
if (commit->parents->next) {
add_to_msg(", reversing\nchanges made to ");
add_to_msg(sha1_to_hex(parent->object.sha1));
}
add_to_msg(".\n");
} else {
base = parent;
next = commit;
set_author_ident_env(message);
add_message_to_msg(message);
if (no_replay) {
add_to_msg("(cherry picked from commit ");
add_to_msg(sha1_to_hex(commit->object.sha1));
add_to_msg(")\n");
}
}
read_cache();
init_merge_options(&o);
o.branch1 = "HEAD";
o.branch2 = oneline;
head_tree = parse_tree_indirect(head);
next_tree = next ? next->tree : empty_tree();
base_tree = base ? base->tree : empty_tree();
clean = merge_trees(&o,
head_tree,
next_tree, base_tree, &result);
if (active_cache_changed &&
(write_cache(index_fd, active_cache, active_nr) ||
commit_locked_index(&index_lock)))
die("%s: Unable to write new index file", me);
if (!clean) {
add_to_msg("\nConflicts:\n\n");
for (i = 0; i < active_nr;) {
struct cache_entry *ce = active_cache[i++];
if (ce_stage(ce)) {
add_to_msg("\t");
add_to_msg(ce->name);
add_to_msg("\n");
while (i < active_nr && !strcmp(ce->name,
active_cache[i]->name))
i++;
}
}
if (commit_lock_file(&msg_file) < 0)
die ("Error wrapping up %s", defmsg);
fprintf(stderr, "Automatic %s failed.%s\n",
me, help_msg(commit->object.sha1));
rerere();
exit(1);
}
if (commit_lock_file(&msg_file) < 0)
die ("Error wrapping up %s", defmsg);
fprintf(stderr, "Finished one %s.\n", me);
/*
*
* If we are cherry-pick, and if the merge did not result in
* hand-editing, we will hit this commit and inherit the original
* author date and name.
* If we are revert, or if our cherry-pick results in a hand merge,
* we had better say that the current user is responsible for that.
*/
if (!no_commit) {
/* 6 is max possible length of our args array including NULL */
const char *args[6];
int i = 0;
args[i++] = "commit";
args[i++] = "-n";
if (signoff)
args[i++] = "-s";
if (!edit) {
args[i++] = "-F";
args[i++] = defmsg;
}
args[i] = NULL;
return execv_git_cmd(args);
}
free(reencoded_message);
free(defmsg);
return 0;
}
int cmd_revert(int argc, const char **argv, const char *prefix)
{
if (isatty(0))
edit = 1;
no_replay = 1;
action = REVERT;
return revert_or_cherry_pick(argc, argv);
}
int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
{
no_replay = 0;
action = CHERRY_PICK;
return revert_or_cherry_pick(argc, argv);
}