git/builtin/merge-recursive.c

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Fix sparse warnings Fix warnings from 'make check'. - These files don't include 'builtin.h' causing sparse to complain that cmd_* isn't declared: builtin/clone.c:364, builtin/fetch-pack.c:797, builtin/fmt-merge-msg.c:34, builtin/hash-object.c:78, builtin/merge-index.c:69, builtin/merge-recursive.c:22 builtin/merge-tree.c:341, builtin/mktag.c:156, builtin/notes.c:426 builtin/notes.c:822, builtin/pack-redundant.c:596, builtin/pack-refs.c:10, builtin/patch-id.c:60, builtin/patch-id.c:149, builtin/remote.c:1512, builtin/remote-ext.c:240, builtin/remote-fd.c:53, builtin/reset.c:236, builtin/send-pack.c:384, builtin/unpack-file.c:25, builtin/var.c:75 - These files have symbols which should be marked static since they're only file scope: submodule.c:12, diff.c:631, replace_object.c:92, submodule.c:13, submodule.c:14, trace.c:78, transport.c:195, transport-helper.c:79, unpack-trees.c:19, url.c:3, url.c:18, url.c:104, url.c:117, url.c:123, url.c:129, url.c:136, thread-utils.c:21, thread-utils.c:48 - These files redeclare symbols to be different types: builtin/index-pack.c:210, parse-options.c:564, parse-options.c:571, usage.c:49, usage.c:58, usage.c:63, usage.c:72 - These files use a literal integer 0 when they really should use a NULL pointer: daemon.c:663, fast-import.c:2942, imap-send.c:1072, notes-merge.c:362 While we're in the area, clean up some unused #includes in builtin files (mostly exec_cmd.h). Signed-off-by: Stephen Boyd <bebarino@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-22 07:51:05 +00:00
#include "builtin.h"
#include "advice.h"
#include "commit.h"
#include "gettext.h"
#include "hash.h"
#include "tag.h"
#include "merge-recursive.h"
#include "object-name.h"
#include "repository.h"
#include "xdiff-interface.h"
static const char builtin_merge_recursive_usage[] =
"git %s <base>... -- <head> <remote> ...";
static char *better_branch_name(const char *branch)
{
static char githead_env[8 + GIT_MAX_HEXSZ + 1];
char *name;
if (strlen(branch) != the_hash_algo->hexsz)
return xstrdup(branch);
xsnprintf(githead_env, sizeof(githead_env), "GITHEAD_%s", branch);
name = getenv(githead_env);
return xstrdup(name ? name : branch);
}
builtins: mark unused prefix parameters All builtins receive a "prefix" parameter, but it is only useful if they need to adjust filenames given by the user on the command line. For builtins that do not even call parse_options(), they often don't look at the prefix at all, and -Wunused-parameter complains. Let's annotate those to silence the compiler warning. I gave a quick scan of each of these cases, and it seems like they don't have anything they _should_ be using the prefix for (i.e., there is no hidden bug that we are missing). The only questionable cases I saw were: - in git-unpack-file, we create a tempfile which will always be at the root of the repository, even if the command is run from a subdir. Arguably this should be created in the subdir from which we're run (as we report the path only as a relative name). However, nobody has complained, and I'm hesitant to change something that is deep plumbing going back to April 2005 (though I think within our scripts, the sole caller in git-merge-one-file would be OK, as it moves to the toplevel itself). - in fetch-pack, local-filesystem remotes are taken as relative to the project root, not the current directory. So: git init server.git [...put stuff in server.git...] git init client.git cd client.git mkdir subdir cd subdir git fetch-pack ../../server.git ... won't work, as we quietly move to the top of the repository before interpreting the path (so "../server.git" would work). This is weird, but again, nobody has complained and this is how it has always worked. And this is how "git fetch" works, too. Plus it raises questions about how a configured remote like: git config remote.origin.url ../server.git should behave. I can certainly come up with a reasonable set of behavior, but it may not be worth stirring up complications in a plumbing tool. So I've left the behavior untouched in both of those cases. If anybody really wants to revisit them, it's easy enough to drop the UNUSED marker. This commit is just about removing them as obstacles to turning on -Wunused-parameter all the time. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-03-28 20:56:55 +00:00
int cmd_merge_recursive(int argc, const char **argv, const char *prefix UNUSED)
{
const struct object_id *bases[21];
unsigned bases_count = 0;
int i, failed;
struct object_id h1, h2;
struct merge_options o;
char *better1, *better2;
struct commit *result;
init_merge_options(&o, the_repository);
if (argv[0] && ends_with(argv[0], "-subtree"))
o.subtree_shift = "";
if (argc < 4)
usagef(builtin_merge_recursive_usage, argv[0]);
for (i = 1; i < argc; ++i) {
const char *arg = argv[i];
if (starts_with(arg, "--")) {
if (!arg[2])
break;
if (parse_merge_opt(&o, arg + 2))
die(_("unknown option %s"), arg);
continue;
}
if (bases_count < ARRAY_SIZE(bases)-1) {
struct object_id *oid = xmalloc(sizeof(struct object_id));
if (repo_get_oid(the_repository, argv[i], oid))
die(_("could not parse object '%s'"), argv[i]);
bases[bases_count++] = oid;
}
else
warning(Q_("cannot handle more than %d base. "
"Ignoring %s.",
"cannot handle more than %d bases. "
"Ignoring %s.",
ARRAY_SIZE(bases)-1),
(int)ARRAY_SIZE(bases)-1, argv[i]);
}
if (argc - i != 3) /* "--" "<head>" "<remote>" */
die(_("not handling anything other than two heads merge."));
Ensure index matches head before invoking merge machinery, round N This is the bug that just won't die; there always seems to be another form of it somewhere. See the commit message of 55f39cf7551b ("merge: fix misleading pre-merge check documentation", 2018-06-30) for a more detailed explanation), but in short: <quick summary> builtin/merge.c contains this important requirement for merge strategies: ...the index must be in sync with the head commit. The strategies are responsible to ensure this. This condition is important to enforce because there are two likely failure cases when the index isn't in sync with the head commit: * we silently throw away changes the user had staged before the merge * we accidentally (and silently) include changes in the merge that were not part of either of the branches/trees being merged Discarding users' work and mis-merging are both bad outcomes, especially when done silently, so naturally this rule was stated sternly -- but, unfortunately totally ignored in practice unless and until actual bugs were found. But, fear not: the bugs from this were fixed in commit ee6566e8d70d ("[PATCH] Rewrite read-tree", 2005-09-05) through a rewrite of read-tree (again, commit 55f39cf7551b has a more detailed explanation of how this affected merge). And it was fixed again in commit 160252f81626 ("git-merge-ours: make sure our index matches HEAD", 2005-11-03) ...and it was fixed again in commit 3ec62ad9ffba ("merge-octopus: abort if index does not match HEAD", 2016-04-09) ...and again in commit 65170c07d466 ("merge-recursive: avoid incorporating uncommitted changes in a merge", 2017-12-21) ...and again in commit eddd1a411d93 ("merge-recursive: enforce rule that index matches head before merging", 2018-06-30) ...with multiple testcases added to the testsuite that could be enumerated in even more commits. Then, finally, in a patch in the same series as the last fix above, the documentation about this requirement was fixed in commit 55f39cf7551b ("merge: fix misleading pre-merge check documentation", 2018-06-30), and we all lived happily ever after... </quick summary> Unfortunately, "ever after" apparently denotes a limited time and it expired today. The merge-recursive rule to enforce that index matches head was at the beginning of merge_trees() and would only trigger when opt->call_depth was 0. Since merge_recursive() doesn't call merge_trees() until after returning from recursing, this meant that the check wasn't triggered by merge_recursive() until it had first finished all the intermediate merges to create virtual merge bases. That is a potentially HUGE amount of computation (and writing of intermediate merge results into the .git/objects directory) before it errors out and says, in effect, "Sorry, I can't do any merging because you have some local changes that would be overwritten." Trying to enforce that all of merge_trees(), merge_recursive(), and merge_recursive_generic() checked the index == head condition earlier resulted in a bunch of broken tests. It turns out that merge_recursive() has code to drop and reload the cache while recursing to create intermediate virtual merge bases, but unfortunately that code runs even when no recursion is necessary. This unconditional dropping and reloading of the cache masked a few bugs: * builtin/merge-recursive.c: didn't even bother loading the index. * builtin/stash.c: feels like a fake 'builtin' because it repeatedly invokes git subprocesses all over the place, mixed with other operations. In particular, invoking "git reset" will reset the index on disk, but the parent process that invoked it won't automatically have its in-memory index updated. * t3030-merge-recursive.h: this test has always been broken in that it didn't make sure to make index match head before running. But, it didn't care about the index or even the merge result, just the verbose output while running. While commit eddd1a411d93 ("merge-recursive: enforce rule that index matches head before merging", 2018-06-30) should have uncovered this broken test, it used a test_must_fail wrapper around the merge-recursive call because it was known that the merge resulted in a rename/rename conflict. Thus, that fix only made this test fail for a different reason, and since the index == head check didn't happen until after coming all the way back out of the recursion, the testcase had enough information to pass the one check that it did perform. So, load the index in builtin/merge-recursive.c, reload the in-memory index in builtin/stash.c, and modify the t3030 testcase to correctly setup the index and make sure that the test fails in the expected way (meaning it reports a rename/rename conflict). This makes sure that all callers actually make the index match head. The next commit will then enforce the condition that index matches head earlier so this problem doesn't return in the future. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-17 18:41:28 +00:00
if (repo_read_index_unmerged(the_repository))
die_resolve_conflict("merge");
o.branch1 = argv[++i];
o.branch2 = argv[++i];
if (repo_get_oid(the_repository, o.branch1, &h1))
die(_("could not resolve ref '%s'"), o.branch1);
if (repo_get_oid(the_repository, o.branch2, &h2))
die(_("could not resolve ref '%s'"), o.branch2);
o.branch1 = better1 = better_branch_name(o.branch1);
o.branch2 = better2 = better_branch_name(o.branch2);
if (o.verbosity >= 3)
printf(_("Merging %s with %s\n"), o.branch1, o.branch2);
failed = merge_recursive_generic(&o, &h1, &h2, bases_count, bases, &result);
free(better1);
free(better2);
if (failed < 0)
return 128; /* die() error code */
return failed;
}