git/builtin/fmt-merge-msg.c

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#include "builtin.h"
#include "config.h"
#include "fmt-merge-msg.h"
#include "gettext.h"
#include "parse-options.h"
#include "wrapper.h"
static const char * const fmt_merge_msg_usage[] = {
N_("git fmt-merge-msg [-m <message>] [--log[=<n>] | --no-log] [--file <file>]"),
NULL
};
int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
{
const char *inpath = NULL;
const char *message = NULL;
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>
2021-12-20 22:53:43 +00:00
char *into_name = NULL;
int shortlog_len = -1;
struct option options[] = {
{ OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
N_("populate log with at most <n> entries from shortlog"),
PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
{ OPTION_INTEGER, 0, "summary", &shortlog_len, N_("n"),
N_("alias for --log (deprecated)"),
PARSE_OPT_OPTARG | PARSE_OPT_HIDDEN, NULL,
DEFAULT_MERGE_LOG_LEN },
OPT_STRING('m', "message", &message, N_("text"),
N_("use <text> as start of 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>
2021-12-20 22:53:43 +00:00
OPT_STRING(0, "into-name", &into_name, N_("name"),
N_("use <name> instead of the real target branch")),
OPT_FILENAME('F', "file", &inpath, N_("file to read from")),
OPT_END()
};
FILE *in = stdin;
struct strbuf input = STRBUF_INIT, output = STRBUF_INIT;
int ret;
struct fmt_merge_msg_opts opts;
git_config(fmt_merge_msg_config, NULL);
argc = parse_options(argc, argv, prefix, options, fmt_merge_msg_usage,
0);
if (argc > 0)
usage_with_options(fmt_merge_msg_usage, options);
if (shortlog_len < 0)
shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
if (inpath && strcmp(inpath, "-")) {
in = fopen(inpath, "r");
if (!in)
die_errno("cannot open '%s'", inpath);
}
if (strbuf_read(&input, fileno(in), 0) < 0)
die_errno("could not read input file");
if (message)
strbuf_addstr(&output, message);
memset(&opts, 0, sizeof(opts));
opts.add_title = !message;
opts.credit_people = 1;
opts.shortlog_len = shortlog_len;
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>
2021-12-20 22:53:43 +00:00
opts.into_name = into_name;
ret = fmt_merge_msg(&input, &output, &opts);
if (ret)
return ret;
write_in_full(STDOUT_FILENO, output.buf, output.len);
return 0;
}