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git/builtin/merge.c

1769 lines
48 KiB

/*
* Builtin "git merge"
*
* Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
*
* Based on git-merge.sh by Junio C Hamano.
*/
#define USE_THE_INDEX_COMPATIBILITY_MACROS
#include "cache.h"
#include "config.h"
#include "parse-options.h"
#include "builtin.h"
#include "lockfile.h"
#include "run-command.h"
#include "hook.h"
#include "diff.h"
#include "diff-merges.h"
#include "refs.h"
#include "refspec.h"
#include "commit.h"
#include "diffcore.h"
#include "revision.h"
#include "unpack-trees.h"
#include "cache-tree.h"
#include "dir.h"
#include "utf8.h"
#include "log-tree.h"
#include "color.h"
#include "rerere.h"
#include "help.h"
#include "merge-recursive.h"
#include "merge-ort-wrappers.h"
#include "resolve-undo.h"
#include "remote.h"
#include "fmt-merge-msg.h"
commit: teach --gpg-sign option This uses the gpg-interface.[ch] to allow signing the commit, i.e. $ git commit --gpg-sign -m foo You need a passphrase to unlock the secret key for user: "Junio C Hamano <gitster@pobox.com>" 4096-bit RSA key, ID 96AFE6CB, created 2011-10-03 (main key ID 713660A7) [master 8457d13] foo 1 files changed, 1 insertions(+), 0 deletions(-) The lines of GPG detached signature are placed in a new multi-line header field, instead of tucking the signature block at the end of the commit log message text (similar to how signed tag is done), for multiple reasons: - The signature won't clutter output from "git log" and friends if it is in the extra header. If we place it at the end of the log message, we would need to teach "git log" and friends to strip the signature block with an option. - Teaching new versions of "git log" and "gitk" to optionally verify and show signatures is cleaner if we structurally know where the signature block is (instead of scanning in the commit log message). - The signature needs to be stripped upon various commit rewriting operations, e.g. rebase, filter-branch, etc. They all already ignore unknown headers, but if we place signature in the log message, all of these tools (and third-party tools) also need to learn how a signature block would look like. - When we added the optional encoding header, all the tools (both in tree and third-party) that acts on the raw commit object should have been fixed to ignore headers they do not understand, so it is not like that new header would be more likely to break than extra text in the commit. A commit made with the above sample sequence would look like this: $ git cat-file commit HEAD tree 3cd71d90e3db4136e5260ab54599791c4f883b9d parent b87755351a47b09cb27d6913e6e0e17e6254a4d4 author Junio C Hamano <gitster@pobox.com> 1317862251 -0700 committer Junio C Hamano <gitster@pobox.com> 1317862251 -0700 gpgsig -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQIcBAABAgAGBQJOjPtrAAoJELC16IaWr+bL4TMP/RSe2Y/jYnCkds9unO5JEnfG ... =dt98 -----END PGP SIGNATURE----- foo but "git log" (unless you ask for it with --pretty=raw) output is not cluttered with the signature information. Signed-off-by: Junio C Hamano <gitster@pobox.com>
11 years ago
#include "gpg-interface.h"
#include "sequencer.h"
#include "string-list.h"
#include "packfile.h"
#include "tag.h"
#include "alias.h"
#include "branch.h"
#include "commit-reach.h"
#include "wt-status.h"
#include "commit-graph.h"
#define DEFAULT_TWOHEAD (1<<0)
#define DEFAULT_OCTOPUS (1<<1)
#define NO_FAST_FORWARD (1<<2)
#define NO_TRIVIAL (1<<3)
struct strategy {
const char *name;
unsigned attr;
};
static const char * const builtin_merge_usage[] = {
N_("git merge [<options>] [<commit>...]"),
"git merge --abort",
"git merge --continue",
NULL
};
static int show_diffstat = 1, shortlog_len = -1, squash;
static int option_commit = -1;
static int option_edit = -1;
static int allow_trivial = 1, have_message, verify_signatures;
gpg-interface: add minTrustLevel as a configuration option Previously, signature verification for merge and pull operations checked if the key had a trust-level of either TRUST_NEVER or TRUST_UNDEFINED in verify_merge_signature(). If that was the case, the process die()d. The other code paths that did signature verification relied entirely on the return code from check_commit_signature(). And signatures made with a good key, irregardless of its trust level, was considered valid by check_commit_signature(). This difference in behavior might induce users to erroneously assume that the trust level of a key in their keyring is always considered by Git, even for operations where it is not (e.g. during a verify-commit or verify-tag). The way it worked was by gpg-interface.c storing the result from the key/signature status *and* the lowest-two trust levels in the `result` member of the signature_check structure (the last of these status lines that were encountered got written to `result`). These are documented in GPG under the subsection `General status codes` and `Key related`, respectively [1]. The GPG documentation says the following on the TRUST_ status codes [1]: """ These are several similar status codes: - TRUST_UNDEFINED <error_token> - TRUST_NEVER <error_token> - TRUST_MARGINAL [0 [<validation_model>]] - TRUST_FULLY [0 [<validation_model>]] - TRUST_ULTIMATE [0 [<validation_model>]] For good signatures one of these status lines are emitted to indicate the validity of the key used to create the signature. The error token values are currently only emitted by gpgsm. """ My interpretation is that the trust level is conceptionally different from the validity of the key and/or signature. That seems to also have been the assumption of the old code in check_signature() where a result of 'G' (as in GOODSIG) and 'U' (as in TRUST_NEVER or TRUST_UNDEFINED) were both considered a success. The two cases where a result of 'U' had special meaning were in verify_merge_signature() (where this caused git to die()) and in format_commit_one() (where it affected the output of the %G? format specifier). I think it makes sense to refactor the processing of TRUST_ status lines such that users can configure a minimum trust level that is enforced globally, rather than have individual parts of git (e.g. merge) do it themselves (except for a grace period with backward compatibility). I also think it makes sense to not store the trust level in the same struct member as the key/signature status. While the presence of a TRUST_ status code does imply that the signature is good (see the first paragraph in the included snippet above), as far as I can tell, the order of the status lines from GPG isn't well-defined; thus it would seem plausible that the trust level could be overwritten with the key/signature status if they were stored in the same member of the signature_check structure. This patch introduces a new configuration option: gpg.minTrustLevel. It consolidates trust-level verification to gpg-interface.c and adds a new `trust_level` member to the signature_check structure. Backward-compatibility is maintained by introducing a special case in verify_merge_signature() such that if no user-configurable gpg.minTrustLevel is set, then the old behavior of rejecting TRUST_UNDEFINED and TRUST_NEVER is enforced. If, on the other hand, gpg.minTrustLevel is set, then that value overrides the old behavior. Similarly, the %G? format specifier will continue show 'U' for signatures made with a key that has a trust level of TRUST_UNDEFINED or TRUST_NEVER, even though the 'U' character no longer exist in the `result` member of the signature_check structure. A new format specifier, %GT, is also introduced for users that want to show all possible trust levels for a signature. Another approach would have been to simply drop the trust-level requirement in verify_merge_signature(). This would also have made the behavior consistent with other parts of git that perform signature verification. However, requiring a minimum trust level for signing keys does seem to have a real-world use-case. For example, the build system used by the Qubes OS project currently parses the raw output from verify-tag in order to assert a minimum trust level for keys used to sign git tags [2]. [1] https://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=blob;f=doc/doc/DETAILS;h=bd00006e933ac56719b1edd2478ecd79273eae72;hb=refs/heads/master [2] https://github.com/QubesOS/qubes-builder/blob/9674c1991deef45b1a1b1c71fddfab14ba50dccf/scripts/verify-git-tag#L43 Signed-off-by: Hans Jerry Illikainen <hji@dyntopia.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
3 years ago
static int check_trust_level = 1;
static int overwrite_ignore = 1;
static struct strbuf merge_msg = STRBUF_INIT;
static struct strategy **use_strategies;
static size_t use_strategies_nr, use_strategies_alloc;
static const char **xopts;
static size_t xopts_nr, xopts_alloc;
static const char *branch;
static char *branch_mergeoptions;
static int verbosity;
static int allow_rerere_auto;
static int abort_current_merge;
static int quit_current_merge;
static int continue_current_merge;
merge: refuse to create too cool a merge by default While it makes sense to allow merging unrelated histories of two projects that started independently into one, in the way "gitk" was merged to "git" itself aka "the coolest merge ever", such a merge is still an unusual event. Worse, if somebody creates an independent history by starting from a tarball of an established project and sends a pull request to the original project, "git merge" however happily creates such a merge without any sign of something unusual is happening. Teach "git merge" to refuse to create such a merge by default, unless the user passes a new "--allow-unrelated-histories" option to tell it that the user is aware that two unrelated projects are merged. Because such a "two project merge" is a rare event, a configuration option to always allow such a merge is not added. We could add the same option to "git pull" and have it passed through to underlying "git merge". I do not have a fundamental opposition against such a feature, but this commit does not do so and instead leaves it as low-hanging fruit for others, because such a "two project merge" would be done after fetching the other project into some location in the working tree of an existing project and making sure how well they fit together, it is sufficient to allow a local merge without such an option pass-through from "git pull" to "git merge". Many tests that are updated by this patch does the pass-through manually by turning: git pull something into its equivalent: git fetch something && git merge --allow-unrelated-histories FETCH_HEAD If somebody is inclined to add such an option, updated tests in this change need to be adjusted back to: git pull --allow-unrelated-histories something Signed-off-by: Junio C Hamano <gitster@pobox.com>
7 years ago
static int allow_unrelated_histories;
static int show_progress = -1;
static int default_to_upstream = 1;
static int signoff;
commit: teach --gpg-sign option This uses the gpg-interface.[ch] to allow signing the commit, i.e. $ git commit --gpg-sign -m foo You need a passphrase to unlock the secret key for user: "Junio C Hamano <gitster@pobox.com>" 4096-bit RSA key, ID 96AFE6CB, created 2011-10-03 (main key ID 713660A7) [master 8457d13] foo 1 files changed, 1 insertions(+), 0 deletions(-) The lines of GPG detached signature are placed in a new multi-line header field, instead of tucking the signature block at the end of the commit log message text (similar to how signed tag is done), for multiple reasons: - The signature won't clutter output from "git log" and friends if it is in the extra header. If we place it at the end of the log message, we would need to teach "git log" and friends to strip the signature block with an option. - Teaching new versions of "git log" and "gitk" to optionally verify and show signatures is cleaner if we structurally know where the signature block is (instead of scanning in the commit log message). - The signature needs to be stripped upon various commit rewriting operations, e.g. rebase, filter-branch, etc. They all already ignore unknown headers, but if we place signature in the log message, all of these tools (and third-party tools) also need to learn how a signature block would look like. - When we added the optional encoding header, all the tools (both in tree and third-party) that acts on the raw commit object should have been fixed to ignore headers they do not understand, so it is not like that new header would be more likely to break than extra text in the commit. A commit made with the above sample sequence would look like this: $ git cat-file commit HEAD tree 3cd71d90e3db4136e5260ab54599791c4f883b9d parent b87755351a47b09cb27d6913e6e0e17e6254a4d4 author Junio C Hamano <gitster@pobox.com> 1317862251 -0700 committer Junio C Hamano <gitster@pobox.com> 1317862251 -0700 gpgsig -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQIcBAABAgAGBQJOjPtrAAoJELC16IaWr+bL4TMP/RSe2Y/jYnCkds9unO5JEnfG ... =dt98 -----END PGP SIGNATURE----- foo but "git log" (unless you ask for it with --pretty=raw) output is not cluttered with the signature information. Signed-off-by: Junio C Hamano <gitster@pobox.com>
11 years ago
static const char *sign_commit;
static int autostash;
static int no_verify;
merge: allow to pretend a merge is made into a different branch When a series of patches for a topic-B depends on having topic-A, the workflow to prepare the topic-B branch would look like this: $ git checkout -b topic-B main $ git merge --no-ff --no-edit topic-A $ git am <mbox-for-topic-B When topic-A gets updated, recreating the first merge and rebasing the rest of the topic-B, all on detached HEAD, is a useful technique. After updating topic-A with its new round of patches: $ git checkout topic-B $ prev=$(git rev-parse 'HEAD^{/^Merge branch .topic-A. into}') $ git checkout --detach $prev^1 $ git merge --no-ff --no-edit topic-A $ git rebase --onto HEAD $prev @{-1}^0 $ git checkout -B @{-1} This will (0) check out the current topic-B. (1) find the previous merge of topic-A into topic-B. (2) detach the HEAD to the parent of the previous merge. (3) merge the updated topic-A to it. (4) reapply the patches to rebuild the rest of topic-B. (5) update topic-B with the result. without contaminating the reflog of topic-B too much. topic-B@{1} is the "logically previous" state before topic-A got updated, for example. At (4), comparison (e.g. range-diff) between HEAD and @{-1} is a meaningful way to sanity check the result, and the same can be done at (5) by comparing topic-B and topic-B@{1}. But there is one glitch. The merge into the detached HEAD done in the step (3) above gives us "Merge branch 'topic-A' into HEAD", and does not say "into topic-B". Teach the "--into-name=<branch>" option to "git merge" and its underlying "git fmt-merge-message", to pretend as if we were merging into <branch>, no matter what branch we are actually merging into, when they prepare the merge message. The pretend name honors the usual "into <target>" suppression mechanism, which can be seen in the tests added here. Signed-off-by: Junio C Hamano <gitster@pobox.com>
11 months ago
static char *into_name;
static struct strategy all_strategy[] = {
Change default merge backend from recursive to ort There are a few reasons to switch the default: * Correctness * Extensibility * Performance I'll provide some summaries about each. === Correctness === The original impetus for a new merge backend was to fix issues that were difficult to fix within recursive's design. The success with this goal is perhaps most easily demonstrated by running the following: $ git grep -2 KNOWN_FAILURE t/ | grep -A 4 GIT_TEST_MERGE_ALGORITHM $ git grep test_expect_merge_algorithm.failure.success t/ $ git grep test_expect_merge_algorithm.success.failure t/ In order, these greps show: * Seven sets of submodule tests (10 total tests) that fail with recursive but succeed with ort * 22 other tests that fail with recursive, but succeed with ort * 0 tests that pass with recursive, but fail with ort === Extensibility === Being able to perform merges without touching the working tree or index makes it possible to create new features that were difficult with the old backend: * Merging, cherry-picking, rebasing, reverting in bare repositories... or just on branches that aren't checked out. * `git diff AUTO_MERGE` -- ability to see what changes the user has made to resolve conflicts so far (see commit 5291828df8 ("merge-ort: write $GIT_DIR/AUTO_MERGE whenever we hit a conflict", 2021-03-20) * A --remerge-diff option for log/show, used to show diffs for merges that display the difference between what an automatic merge would have created and what was recorded in the merge. (This option will often result in an empty diff because many merges are clean, but for the non-clean ones it will show how conflicts were fixed including the removal of conflict markers, and also show additional changes made outside of conflict regions to e.g. fix semantic conflicts.) * A --remerge-diff-only option for log/show, similar to --remerge-diff but also showing how cherry-picks or reverts differed from what an automatic cherry-pick or revert would provide. The last three have been implemented already (though only one has been submitted upstream so far; the others were waiting for performance work to complete), and I still plan to implement the first one. === Performance === I'll quote from the summary of my final optimization for merge-ort (while fixing the testcase name from 'no-renames' to 'few-renames'): Timings Infinite merge- merge- Parallelism recursive recursive of rename merge-ort v2.30.0 current detection current ---------- --------- ----------- --------- few-renames: 18.912 s 18.030 s 11.699 s 198.3 ms mega-renames: 5964.031 s 361.281 s 203.886 s 661.8 ms just-one-mega: 149.583 s 11.009 s 7.553 s 264.6 ms Speedup factors Infinite merge- merge- Parallelism recursive recursive of rename v2.30.0 current detection merge-ort ---------- --------- ----------- --------- few-renames: 1 1.05 1.6 95 mega-renames: 1 16.5 29 9012 just-one-mega: 1 13.6 20 565 And, for partial clone users: Factor reduction in number of objects needed Infinite merge- merge- Parallelism recursive recursive of rename v2.30.0 current detection merge-ort ---------- --------- ----------- --------- mega-renames: 1 1 1 181.3 Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 year ago
{ "recursive", NO_TRIVIAL },
{ "octopus", DEFAULT_OCTOPUS },
Change default merge backend from recursive to ort There are a few reasons to switch the default: * Correctness * Extensibility * Performance I'll provide some summaries about each. === Correctness === The original impetus for a new merge backend was to fix issues that were difficult to fix within recursive's design. The success with this goal is perhaps most easily demonstrated by running the following: $ git grep -2 KNOWN_FAILURE t/ | grep -A 4 GIT_TEST_MERGE_ALGORITHM $ git grep test_expect_merge_algorithm.failure.success t/ $ git grep test_expect_merge_algorithm.success.failure t/ In order, these greps show: * Seven sets of submodule tests (10 total tests) that fail with recursive but succeed with ort * 22 other tests that fail with recursive, but succeed with ort * 0 tests that pass with recursive, but fail with ort === Extensibility === Being able to perform merges without touching the working tree or index makes it possible to create new features that were difficult with the old backend: * Merging, cherry-picking, rebasing, reverting in bare repositories... or just on branches that aren't checked out. * `git diff AUTO_MERGE` -- ability to see what changes the user has made to resolve conflicts so far (see commit 5291828df8 ("merge-ort: write $GIT_DIR/AUTO_MERGE whenever we hit a conflict", 2021-03-20) * A --remerge-diff option for log/show, used to show diffs for merges that display the difference between what an automatic merge would have created and what was recorded in the merge. (This option will often result in an empty diff because many merges are clean, but for the non-clean ones it will show how conflicts were fixed including the removal of conflict markers, and also show additional changes made outside of conflict regions to e.g. fix semantic conflicts.) * A --remerge-diff-only option for log/show, similar to --remerge-diff but also showing how cherry-picks or reverts differed from what an automatic cherry-pick or revert would provide. The last three have been implemented already (though only one has been submitted upstream so far; the others were waiting for performance work to complete), and I still plan to implement the first one. === Performance === I'll quote from the summary of my final optimization for merge-ort (while fixing the testcase name from 'no-renames' to 'few-renames'): Timings Infinite merge- merge- Parallelism recursive recursive of rename merge-ort v2.30.0 current detection current ---------- --------- ----------- --------- few-renames: 18.912 s 18.030 s 11.699 s 198.3 ms mega-renames: 5964.031 s 361.281 s 203.886 s 661.8 ms just-one-mega: 149.583 s 11.009 s 7.553 s 264.6 ms Speedup factors Infinite merge- merge- Parallelism recursive recursive of rename v2.30.0 current detection merge-ort ---------- --------- ----------- --------- few-renames: 1 1.05 1.6 95 mega-renames: 1 16.5 29 9012 just-one-mega: 1 13.6 20 565 And, for partial clone users: Factor reduction in number of objects needed Infinite merge- merge- Parallelism recursive recursive of rename v2.30.0 current detection merge-ort ---------- --------- ----------- --------- mega-renames: 1 1 1 181.3 Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 year ago
{ "ort", DEFAULT_TWOHEAD | NO_TRIVIAL },
{ "resolve", 0 },
{ "ours", NO_FAST_FORWARD | NO_TRIVIAL },
{ "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
};
static const char *pull_twohead, *pull_octopus;
enum ff_type {
FF_NO,
FF_ALLOW,
FF_ONLY
};
static enum ff_type fast_forward = FF_ALLOW;
static const char *cleanup_arg;
static enum commit_msg_cleanup_mode cleanup_mode;
static int option_parse_message(const struct option *opt,
const char *arg, int unset)
{
struct strbuf *buf = opt->value;
if (unset)
strbuf_setlen(buf, 0);
else if (arg) {
strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
have_message = 1;
} else
return error(_("switch `m' requires a value"));
return 0;
}
static enum parse_opt_result option_read_message(struct parse_opt_ctx_t *ctx,
const struct option *opt,
const char *arg_not_used,
int unset)
{
struct strbuf *buf = opt->value;
const char *arg;
BUG_ON_OPT_ARG(arg_not_used);
if (unset)
BUG("-F cannot be negated");
if (ctx->opt) {
arg = ctx->opt;
ctx->opt = NULL;
} else if (ctx->argc > 1) {
ctx->argc--;
arg = *++ctx->argv;
} else
return error(_("option `%s' requires a value"), opt->long_name);
if (buf->len)
strbuf_addch(buf, '\n');
if (ctx->prefix && !is_absolute_path(arg))
arg = prefix_filename(ctx->prefix, arg);
if (strbuf_read_file(buf, arg, 0) < 0)
return error(_("could not read file '%s'"), arg);
have_message = 1;
return 0;
}
static struct strategy *get_strategy(const char *name)
{
int i;
struct strategy *ret;
static struct cmdnames main_cmds, other_cmds;
static int loaded;
char *default_strategy = getenv("GIT_TEST_MERGE_ALGORITHM");
if (!name)
return NULL;
if (default_strategy &&
!strcmp(default_strategy, "ort") &&
!strcmp(name, "recursive")) {
name = "ort";
}
for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
if (!strcmp(name, all_strategy[i].name))
return &all_strategy[i];
if (!loaded) {
struct cmdnames not_strategies;
loaded = 1;
memset(&not_strategies, 0, sizeof(struct cmdnames));
load_command_list("git-merge-", &main_cmds, &other_cmds);
for (i = 0; i < main_cmds.cnt; i++) {
int j, found = 0;
struct cmdname *ent = main_cmds.names[i];
for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
if (!strncmp(ent->name, all_strategy[j].name, ent->len)
&& !all_strategy[j].name[ent->len])
found = 1;
if (!found)
add_cmdname(&not_strategies, ent->name, ent->len);
}
exclude_cmds(&main_cmds, &not_strategies);
}
if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
fprintf(stderr, _("Available strategies are:"));
for (i = 0; i < main_cmds.cnt; i++)
fprintf(stderr, " %s", main_cmds.names[i]->name);
fprintf(stderr, ".\n");
if (other_cmds.cnt) {
fprintf(stderr, _("Available custom strategies are:"));
for (i = 0; i < other_cmds.cnt; i++)
fprintf(stderr, " %s", other_cmds.names[i]->name);
fprintf(stderr, ".\n");
}
exit(1);
}
CALLOC_ARRAY(ret, 1);
ret->name = xstrdup(name);
ret->attr = NO_TRIVIAL;
return ret;
}
static void append_strategy(struct strategy *s)
{
ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
use_strategies[use_strategies_nr++] = s;
}
static int option_parse_strategy(const struct option *opt,
const char *name, int unset)
{
if (unset)
return 0;
append_strategy(get_strategy(name));
return 0;
}
static int option_parse_x(const struct option *opt,
const char *arg, int unset)
{
if (unset)
return 0;
ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
xopts[xopts_nr++] = xstrdup(arg);
return 0;
}
static int option_parse_n(const struct option *opt,
const char *arg, int unset)
{
assert NOARG/NONEG behavior of parse-options callbacks When we define a parse-options callback, the flags we put in the option struct must match what the callback expects. For example, a callback which does not handle the "unset" parameter should only be used with PARSE_OPT_NONEG. But since the callback and the option struct are not defined next to each other, it's easy to get this wrong (as earlier patches in this series show). Fortunately, the compiler can help us here: compiling with -Wunused-parameters can show us which callbacks ignore their "unset" parameters (and likewise, ones that ignore "arg" expect to be triggered with PARSE_OPT_NOARG). But after we've inspected a callback and determined that all of its callers use the right flags, what do we do next? We'd like to silence the compiler warning, but do so in a way that will catch any wrong calls in the future. We can do that by actually checking those variables and asserting that they match our expectations. Because this is such a common pattern, we'll introduce some helper macros. The resulting messages aren't as descriptive as we could make them, but the file/line information from BUG() is enough to identify the problem (and anyway, the point is that these should never be seen). Each of the annotated callbacks in this patch triggers -Wunused-parameters, and was manually inspected to make sure all callers use the correct options (so none of these BUGs should be triggerable). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
4 years ago
BUG_ON_OPT_ARG(arg);
show_diffstat = unset;
return 0;
}
static struct option builtin_merge_options[] = {
OPT_CALLBACK_F('n', NULL, NULL, NULL,
N_("do not show a diffstat at the end of the merge"),
PARSE_OPT_NOARG, option_parse_n),
OPT_BOOL(0, "stat", &show_diffstat,
N_("show a diffstat at the end of the merge")),
OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
{ OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
N_("add (at most <n>) entries from shortlog to merge commit message"),
PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
OPT_BOOL(0, "squash", &squash,
N_("create a single commit instead of doing a merge")),
OPT_BOOL(0, "commit", &option_commit,
N_("perform a commit if the merge succeeds (default)")),
merge: use editor by default in interactive sessions Traditionally, a cleanly resolved merge was committed by "git merge" using the auto-generated merge commit log message without invoking the editor. After 5 years of use in the field, it turns out that people perform too many unjustified merges of the upstream history into their topic branches. These merges are not just useless, but they are often not explained well, and making the end result unreadable when it gets time for merging their history back to their upstream. Earlier we added the "--edit" option to the command, so that people can edit the log message to explain and justify their merge commits. Let's take it one step further and spawn the editor by default when we are in an interactive session (i.e. the standard input and the standard output are pointing at the same tty device). There may be existing scripts that leave the standard input and the standard output of the "git merge" connected to whatever environment the scripts were started, and such invocation might trigger the above "interactive session" heuristics. GIT_MERGE_AUTOEDIT environment variable can be set to "no" at the beginning of such scripts to use the historical behaviour while the script runs. Note that this backward compatibility is meant only for scripts, and we deliberately do *not* support "merge.edit = yes/no/auto" configuration option to allow people to keep the historical behaviour. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
11 years ago
OPT_BOOL('e', "edit", &option_edit,
N_("edit message before committing")),
OPT_CLEANUP(&cleanup_arg),
OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
OPT_SET_INT_F(0, "ff-only", &fast_forward,
N_("abort if fast-forward is not possible"),
FF_ONLY, PARSE_OPT_NONEG),
OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
OPT_BOOL(0, "verify-signatures", &verify_signatures,
N_("verify that the named commit has a valid GPG signature")),
OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
N_("merge strategy to use"), option_parse_strategy),
OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
N_("option for selected merge strategy"), option_parse_x),
OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
N_("merge commit message (for a non-fast-forward merge)"),
option_parse_message),
{ OPTION_LOWLEVEL_CALLBACK, 'F', "file", &merge_msg, N_("path"),
N_("read message from file"), PARSE_OPT_NONEG,
NULL, 0, option_read_message },
merge: allow to pretend a merge is made into a different branch When a series of patches for a topic-B depends on having topic-A, the workflow to prepare the topic-B branch would look like this: $ git checkout -b topic-B main $ git merge --no-ff --no-edit topic-A $ git am <mbox-for-topic-B When topic-A gets updated, recreating the first merge and rebasing the rest of the topic-B, all on detached HEAD, is a useful technique. After updating topic-A with its new round of patches: $ git checkout topic-B $ prev=$(git rev-parse 'HEAD^{/^Merge branch .topic-A. into}') $ git checkout --detach $prev^1 $ git merge --no-ff --no-edit topic-A $ git rebase --onto HEAD $prev @{-1}^0 $ git checkout -B @{-1} This will (0) check out the current topic-B. (1) find the previous merge of topic-A into topic-B. (2) detach the HEAD to the parent of the previous merge. (3) merge the updated topic-A to it. (4) reapply the patches to rebuild the rest of topic-B. (5) update topic-B with the result. without contaminating the reflog of topic-B too much. topic-B@{1} is the "logically previous" state before topic-A got updated, for example. At (4), comparison (e.g. range-diff) between HEAD and @{-1} is a meaningful way to sanity check the result, and the same can be done at (5) by comparing topic-B and topic-B@{1}. But there is one glitch. The merge into the detached HEAD done in the step (3) above gives us "Merge branch 'topic-A' into HEAD", and does not say "into topic-B". Teach the "--into-name=<branch>" option to "git merge" and its underlying "git fmt-merge-message", to pretend as if we were merging into <branch>, no matter what branch we are actually merging into, when they prepare the merge message. The pretend name honors the usual "into <target>" suppression mechanism, which can be seen in the tests added here. Signed-off-by: Junio C Hamano <gitster@pobox.com>
11 months ago
OPT_STRING(0, "into-name", &into_name, N_("name"),
N_("use <name> instead of the real target")),
OPT__VERBOSITY(&verbosity),
OPT_BOOL(0, "abort", &abort_current_merge,
N_("abort the current in-progress merge")),
OPT_BOOL(0, "quit", &quit_current_merge,
N_("--abort but leave index and working tree alone")),
OPT_BOOL(0, "continue", &continue_current_merge,
N_("continue the current in-progress merge")),
merge: refuse to create too cool a merge by default While it makes sense to allow merging unrelated histories of two projects that started independently into one, in the way "gitk" was merged to "git" itself aka "the coolest merge ever", such a merge is still an unusual event. Worse, if somebody creates an independent history by starting from a tarball of an established project and sends a pull request to the original project, "git merge" however happily creates such a merge without any sign of something unusual is happening. Teach "git merge" to refuse to create such a merge by default, unless the user passes a new "--allow-unrelated-histories" option to tell it that the user is aware that two unrelated projects are merged. Because such a "two project merge" is a rare event, a configuration option to always allow such a merge is not added. We could add the same option to "git pull" and have it passed through to underlying "git merge". I do not have a fundamental opposition against such a feature, but this commit does not do so and instead leaves it as low-hanging fruit for others, because such a "two project merge" would be done after fetching the other project into some location in the working tree of an existing project and making sure how well they fit together, it is sufficient to allow a local merge without such an option pass-through from "git pull" to "git merge". Many tests that are updated by this patch does the pass-through manually by turning: git pull something into its equivalent: git fetch something && git merge --allow-unrelated-histories FETCH_HEAD If somebody is inclined to add such an option, updated tests in this change need to be adjusted back to: git pull --allow-unrelated-histories something Signed-off-by: Junio C Hamano <gitster@pobox.com>
7 years ago
OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
N_("allow merging unrelated histories")),
OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
{ OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
OPT_AUTOSTASH(&autostash),
OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
Documentation: stylistically normalize references to Signed-off-by: Ted reported an old typo in the git-commit.txt and merge-options.txt. Namely, the phrase "Signed-off-by line" was used without either a definite nor indefinite article. Upon examination, it seems that the documentation (including items in Documentation/, but also option help strings) have been quite inconsistent on usage when referring to `Signed-off-by`. First, very few places used a definite or indefinite article with the phrase "Signed-off-by line", but that was the initial typo that led to this investigation. So, normalize using either an indefinite or definite article consistently. The original phrasing, in Commit 3f971fc425b (Documentation updates, 2005-08-14), is "Add Signed-off-by line". Commit 6f855371a53 (Add --signoff, --check, and long option-names. 2005-12-09) switched to using "Add `Signed-off-by:` line", but didn't normalize the former commit to match. Later commits seem to have cut and pasted from one or the other, which is likely how the usage became so inconsistent. Junio stated on the git mailing list in <xmqqy2k1dfoh.fsf@gitster.c.googlers.com> a preference to leave off the colon. Thus, prefer `Signed-off-by` (with backticks) for the documentation files and Signed-off-by (without backticks) for option help strings. Additionally, Junio argued that "trailer" is now the standard term to refer to `Signed-off-by`, saying that "becomes plenty clear that we are not talking about any random line in the log message". As such, prefer "trailer" over "line" anywhere the former word fits. However, leave alone those few places in documentation that use Signed-off-by to refer to the process (rather than the specific trailer), or in places where mail headers are generally discussed in comparison with Signed-off-by. Reported-by: "Theodore Y. Ts'o" <tytso@mit.edu> Signed-off-by: Bradley M. Kuhn <bkuhn@sfconservancy.org> Acked-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2 years ago
OPT_BOOL(0, "signoff", &signoff, N_("add a Signed-off-by trailer")),
OPT_BOOL(0, "no-verify", &no_verify, N_("bypass pre-merge-commit and commit-msg hooks")),
OPT_END()
};
static int save_state(struct object_id *stash)
{
int len;
struct child_process cp = CHILD_PROCESS_INIT;
struct strbuf buffer = STRBUF_INIT;
int rc = -1;
strvec_pushl(&cp.args, "stash", "create", NULL);
cp.out = -1;
cp.git_cmd = 1;
if (start_command(&cp))
die(_("could not run stash."));
len = strbuf_read(&buffer, cp.out, 1024);
close(cp.out);
if (finish_command(&cp) || len < 0)
die(_("stash failed"));
else if (!len) /* no changes */
goto out;
strbuf_setlen(&buffer, buffer.len-1);
if (get_oid(buffer.buf, stash))
die(_("not a valid object: %s"), buffer.buf);
rc = 0;
out:
strbuf_release(&buffer);
return rc;
}
static void read_empty(const struct object_id *oid, int verbose)
{
int i = 0;
const char *args[7];
args[i++] = "read-tree";
if (verbose)
args[i++] = "-v";
args[i++] = "-m";
args[i++] = "-u";
args[i++] = empty_tree_oid_hex();
args[i++] = oid_to_hex(oid);
args[i] = NULL;
if (run_command_v_opt(args, RUN_GIT_CMD))
die(_("read-tree failed"));
}
static void reset_hard(const struct object_id *oid, int verbose)
{
int i = 0;
const char *args[6];
args[i++] = "read-tree";
if (verbose)
args[i++] = "-v";
args[i++] = "--reset";
args[i++] = "-u";
args[i++] = oid_to_hex(oid);
args[i] = NULL;
if (run_command_v_opt(args, RUN_GIT_CMD))
die(_("read-tree failed"));
}
static void restore_state(const struct object_id *head,
const struct object_id *stash)
{
struct strbuf sb = STRBUF_INIT;
const char *args[] = { "stash", "apply", NULL, NULL };
if (is_null_oid(stash))
return;
reset_hard(head, 1);
args[2] = oid_to_hex(stash);
/*
* It is OK to ignore error here, for example when there was
* nothing to restore.
*/
run_command_v_opt(args, RUN_GIT_CMD);
strbuf_release(&sb);
refresh_cache(REFRESH_QUIET);
}
/* This is called when no merge was necessary. */
static void finish_up_to_date(void)
{
if (verbosity >= 0) {
if (squash)
puts(_("Already up to date. (nothing to squash)"));
else
puts(_("Already up to date."));
}
remove_merge_branch_state(the_repository);
}
static void squash_message(struct commit *commit, struct commit_list *remoteheads)
{
struct rev_info rev;
struct strbuf out = STRBUF_INIT;
struct commit_list *j;
struct pretty_print_context ctx = {0};
printf(_("Squash commit -- not updating HEAD\n"));
repo_init_revisions(the_repository, &rev, NULL);
diff_merges_suppress(&rev);
rev.commit_format = CMIT_FMT_MEDIUM;
commit->object.flags |= UNINTERESTING;
add_pending_object(&rev, &commit->object, NULL);
for (j = remoteheads; j; j = j->next)
add_pending_object(&rev, &j->item->object, NULL);
setup_revisions(0, NULL, &rev, NULL);
if (prepare_revision_walk(&rev))
die(_("revision walk setup failed"));
ctx.abbrev = rev.abbrev;
ctx.date_mode = rev.date_mode;
ctx.fmt = rev.commit_format;
strbuf_addstr(&out, "Squashed commit of the following:\n");
while ((commit = get_revision(&rev)) != NULL) {
strbuf_addch(&out, '\n');
strbuf_addf(&out, "commit %s\n",
oid_to_hex(&commit->object.oid));
pretty_print_commit(&ctx, commit, &out);
}
write_file_buf(git_path_squash_msg(the_repository), out.buf, out.len);
strbuf_release(&out);
release_revisions(&rev);
}
static void finish(struct commit *head_commit,
struct commit_list *remoteheads,
const struct object_id *new_head, const char *msg)
{
struct strbuf reflog_message = STRBUF_INIT;
const struct object_id *head = &head_commit->object.oid;
if (!msg)
strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
else {
if (verbosity >= 0)
printf("%s\n", msg);
strbuf_addf(&reflog_message, "%s: %s",
getenv("GIT_REFLOG_ACTION"), msg);
}
if (squash) {
squash_message(head_commit, remoteheads);
} else {
if (verbosity >= 0 && !merge_msg.len)
printf(_("No merge message -- not updating HEAD\n"));
else {
update_ref(reflog_message.buf, "HEAD", new_head, head,
0, UPDATE_REFS_DIE_ON_ERR);
/*
* We ignore errors in 'gc --auto', since the
* user should see them.
*/
run_auto_maintenance(verbosity < 0);
}
}
if (new_head && show_diffstat) {
struct diff_options opts;
repo_diff_setup(the_repository, &opts);
opts.stat_width = -1; /* use full terminal width */
opts.stat_graph_width = -1; /* respect statGraphWidth config */
opts.output_format |=
DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
opts.detect_rename = DIFF_DETECT_RENAME;
diff_setup_done(&opts);
diff_tree_oid(head, new_head, "", &opts);
diffcore_std(&opts);
diff_flush(&opts);
}
/* Run a post-merge hook */
run_hooks_l("post-merge", squash ? "1" : "0", NULL);
apply_autostash(git_path_merge_autostash(the_repository));
strbuf_release(&reflog_message);
}
/* Get the name for the merge commit's message. */