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