merge/pull: verify GPG signatures of commits being merged

diff --git a/builtin/merge.c b/builtin/merge.c
index 9307e9c726587461d002530938dbf2c0d74d55a1..e57c42c622b0d92c08bebf8eca8560503fe78b80 100644 (file)
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -49,7 +49,7 @@ static const char * const builtin_merge_usage[] = {
 static int show_diffstat = 1, shortlog_len = -1, squash;
 static int option_commit = 1, allow_fast_forward = 1;
 static int fast_forward_only, option_edit = -1;
-static int allow_trivial = 1, have_message;
+static int allow_trivial = 1, have_message, verify_signatures;
 static int overwrite_ignore = 1;
 static struct strbuf merge_msg = STRBUF_INIT;
 static struct strategy **use_strategies;
@@ -199,6 +199,8 @@ static struct option builtin_merge_options[] = {
        OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
                N_("abort if fast-forward is not possible")),
        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"),
@@ -788,17 +790,16 @@ static const char merge_editor_comment[] =
 N_("Please enter a commit message to explain why this merge is necessary,\n"
    "especially if it merges an updated upstream into a topic branch.\n"
    "\n"
-   "Lines starting with '#' will be ignored, and an empty message aborts\n"
+   "Lines starting with '%c' will be ignored, and an empty message aborts\n"
    "the commit.\n");
 
 static void prepare_to_commit(struct commit_list *remoteheads)
 {
        struct strbuf msg = STRBUF_INIT;
-       const char *comment = _(merge_editor_comment);
        strbuf_addbuf(&msg, &merge_msg);
        strbuf_addch(&msg, '\n');
        if (0 < option_edit)
-               strbuf_add_lines(&msg, "# ", comment, strlen(comment));
+               strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
        write_merge_msg(&msg);
        if (run_hook(get_index_file(), "prepare-commit-msg",
                     git_path("MERGE_MSG"), "merge", NULL, NULL))
@@ -1234,6 +1235,36 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                usage_with_options(builtin_merge_usage,
                        builtin_merge_options);
 
+       if (verify_signatures) {
+               for (p = remoteheads; p; p = p->next) {
+                       struct commit *commit = p->item;
+                       char hex[41];
+                       struct signature_check signature_check;
+                       memset(&signature_check, 0, sizeof(signature_check));
+
+                       check_commit_signature(commit, &signature_check);
+
+                       strcpy(hex, find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
+                       switch (signature_check.result) {
+                       case 'G':
+                               break;
+                       case 'B':
+                               die(_("Commit %s has a bad GPG signature "
+                                     "allegedly by %s."), hex, signature_check.signer);
+                       default: /* 'N' */
+                               die(_("Commit %s does not have a GPG signature."), hex);
+                       }
+                       if (verbosity >= 0 && signature_check.result == 'G')
+                               printf(_("Commit %s has a good GPG signature by %s\n"),
+                                      hex, signature_check.signer);
+
+                       free(signature_check.gpg_output);
+                       free(signature_check.gpg_status);
+                       free(signature_check.signer);
+                       free(signature_check.key);
+               }
+       }
+
        strbuf_addstr(&buf, "merge");
        for (p = remoteheads; p; p = p->next)
                strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);