format-patch: add --description-file option

This patch makes it possible to directly feed a branch description to
derive the cover letter from. The use case is formatting dynamically
created temporary commits which are not referenced anywhere.

The most obvious alternative would be creating a temporary branch and
setting a description on it, but that doesn't seem particularly elegant.

Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index 373b46fc0de64f4c7426f683b95f24f95ff9cd84..8e515c7dbba1bf9d737d5b1fe56171c805796c57 100644 (file)
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -215,6 +215,10 @@ is greater than 100 bytes, then the mode will be `message`, otherwise
 If `<mode>` is `none`, both the cover letter subject and body will be
 populated with placeholder text.
 
+--description-file=<file>::
+       Use the contents of <file> instead of the branch's description
+       for generating the cover letter.
+
 --subject-prefix=<subject prefix>::
        Instead of the standard '[PATCH]' prefix in the subject
        line, instead use '[<subject prefix>]'. This

diff --git a/builtin/log.c b/builtin/log.c
index db3a88bfe96058679dff1059a6f4769599ee1801..3ced8b22cb81817385e3cc33084f99669e5876b4 100644 (file)
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1253,7 +1253,15 @@ static void show_diffstat(struct rev_info *rev,
        fprintf(rev->diffopt.file, "\n");
 }
 
+static void read_desc_file(struct strbuf *buf, const char *desc_file)
+{
+       if (strbuf_read_file(buf, desc_file, 0) < 0)
+               die_errno(_("unable to read branch description file '%s'"),
+                         desc_file);
+}
+
 static void prepare_cover_text(struct pretty_print_context *pp,
+                              const char *description_file,
                               const char *branch_name,
                               struct strbuf *sb,
                               const char *encoding,
@@ -1267,7 +1275,9 @@ static void prepare_cover_text(struct pretty_print_context *pp,
        if (cover_from_description_mode == COVER_FROM_NONE)
                goto do_pp;
 
-       if (branch_name && *branch_name)
+       if (description_file && *description_file)
+               read_desc_file(&description_sb, description_file);
+       else if (branch_name && *branch_name)
                read_branch_desc(&description_sb, branch_name);
        if (!description_sb.len)
                goto do_pp;
@@ -1313,6 +1323,7 @@ static void get_notes_args(struct strvec *arg, struct rev_info *rev)
 static void make_cover_letter(struct rev_info *rev, int use_separate_file,
                              struct commit *origin,
                              int nr, struct commit **list,
+                             const char *description_file,
                              const char *branch_name,
                              int quiet)
 {
@@ -1352,7 +1363,8 @@ static void make_cover_letter(struct rev_info *rev, int use_separate_file,
        pp.rev = rev;
        pp.print_email_subject = 1;
        pp_user_info(&pp, NULL, &sb, committer, encoding);
-       prepare_cover_text(&pp, branch_name, &sb, encoding, need_8bit_cte);
+       prepare_cover_text(&pp, description_file, branch_name, &sb,
+                          encoding, need_8bit_cte);
        fprintf(rev->diffopt.file, "%s\n", sb.buf);
 
        strbuf_release(&sb);
@@ -1893,6 +1905,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
        int quiet = 0;
        const char *reroll_count = NULL;
        char *cover_from_description_arg = NULL;
+       char *description_file = NULL;
        char *branch_name = NULL;
        char *base_commit = NULL;
        struct base_tree_info bases;
@@ -1936,6 +1949,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
                OPT_STRING(0, "cover-from-description", &cover_from_description_arg,
                            N_("cover-from-description-mode"),
                            N_("generate parts of a cover letter based on a branch's description")),
+               OPT_FILENAME(0, "description-file", &description_file,
+                            N_("use branch description from file")),
                OPT_CALLBACK_F(0, "subject-prefix", &rev, N_("prefix"),
                            N_("use [<prefix>] instead of [PATCH]"),
                            PARSE_OPT_NONEG, subject_prefix_callback),
@@ -2321,7 +2336,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
                if (thread)
                        gen_message_id(&rev, "cover");
                make_cover_letter(&rev, !!output_directory,
-                                 origin, nr, list, branch_name, quiet);
+                                 origin, nr, list, description_file, branch_name, quiet);
                print_bases(&bases, rev.diffopt.file);
                print_signature(rev.diffopt.file);
                total++;

diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index 3cf2b7a7fb70ec272d9f12294a26e2a1685c5999..bc0e29b31aa06bec617912c43ecd59e973cb46ed 100755 (executable)
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -1991,6 +1991,20 @@ test_expect_success 'cover letter using branch description (6)' '
        grep hello actual
 '
 
+test_expect_success 'cover letter with --description-file' '
+       test_when_finished "rm -f description.txt" &&
+       cat >description.txt <<-\EOF &&
+       subject from file
+
+       body from file
+       EOF
+       git checkout rebuild-1 &&
+       git format-patch --stdout --cover-letter --cover-from-description auto \
+               --description-file description.txt main >actual &&
+       grep "^Subject: \[PATCH 0/2\] subject from file$" actual &&
+       grep "^body from file$" actual
+'
+
 test_expect_success 'cover letter with nothing' '
        git format-patch --stdout --cover-letter >actual &&
        test_line_count = 0 actual