Merge branch 'rs/pretty-describe'

"git log --format='...'" learned "%(describe)" placeholder.

* rs/pretty-describe:
  archive: expand only a single %(describe) per archive
  pretty: document multiple %(describe) being inconsistent
  t4205: assert %(describe) test coverage
  pretty: add merge and exclude options to %(describe)
  pretty: add %(describe)

Documentation/gitattributes.txt

@@ -1174,7 +1174,8 @@ tag then no replacement will be done.  The placeholders are the same
 as those for the option `--pretty=format:` of linkgit:git-log[1],
 except that they need to be wrapped like this: `$Format:PLACEHOLDERS$`
 in the file.  E.g. the string `$Format:%H$` will be replaced by the
-commit hash.
+commit hash.  However, only one `%(describe)` placeholder is expanded
+per archive to avoid denial-of-service attacks.
 
 
 Packing objects

Documentation/pretty-formats.txt

@@ -208,6 +208,19 @@ The placeholders are:
 '%cs':: committer date, short format (`YYYY-MM-DD`)
 '%d':: ref names, like the --decorate option of linkgit:git-log[1]
 '%D':: ref names without the " (", ")" wrapping.
+'%(describe[:options])':: human-readable name, like
+			  linkgit:git-describe[1]; empty string for
+			  undescribable commits.  The `describe` string
+			  may be followed by a colon and zero or more
+			  comma-separated options.  Descriptions can be
+			  inconsistent when tags are added or removed at
+			  the same time.
++
+** 'match=<pattern>': Only consider tags matching the given
+   `glob(7)` pattern, excluding the "refs/tags/" prefix.
+** 'exclude=<pattern>': Do not consider tags matching the given
+   `glob(7)` pattern, excluding the "refs/tags/" prefix.
+
 '%S':: ref name given on the command line by which the commit was reached
        (like `git log --source`), only works with `git log`
 '%e':: encoding

archive.c

@@ -37,13 +37,10 @@ void init_archivers(void)
 
 static void format_subst(const struct commit *commit,
 			 const char *src, size_t len,
-			 struct strbuf *buf)
+			 struct strbuf *buf, struct pretty_print_context *ctx)
 {
 	char *to_free = NULL;
 	struct strbuf fmt = STRBUF_INIT;
-	struct pretty_print_context ctx = {0};
-	ctx.date_mode.type = DATE_NORMAL;
-	ctx.abbrev = DEFAULT_ABBREV;
 
 	if (src == buf->buf)
 		to_free = strbuf_detach(buf, NULL);
@@ -61,7 +58,7 @@ static void format_subst(const struct commit *commit,
 		strbuf_add(&fmt, b + 8, c - b - 8);
 
 		strbuf_add(buf, src, b - src);
-		format_commit_message(commit, fmt.buf, buf, &ctx);
+		format_commit_message(commit, fmt.buf, buf, ctx);
 		len -= c + 1 - src;
 		src  = c + 1;
 	}
@@ -94,7 +91,7 @@ static void *object_file_to_archive(const struct archiver_args *args,
 		strbuf_attach(&buf, buffer, *sizep, *sizep + 1);
 		convert_to_working_tree(args->repo->index, path, buf.buf, buf.len, &buf, &meta);
 		if (commit)
-			format_subst(commit, buf.buf, buf.len, &buf);
+			format_subst(commit, buf.buf, buf.len, &buf, args->pretty_ctx);
 		buffer = strbuf_detach(&buf, &size);
 		*sizep = size;
 	}
@@ -633,12 +630,19 @@ int write_archive(int argc, const char **argv, const char *prefix,
 		  const char *name_hint, int remote)
 {
 	const struct archiver *ar = NULL;
+	struct pretty_print_describe_status describe_status = {0};
+	struct pretty_print_context ctx = {0};
 	struct archiver_args args;
 	int rc;
 
 	git_config_get_bool("uploadarchive.allowunreachable", &remote_allow_unreachable);
 	git_config(git_default_config, NULL);
 
+	describe_status.max_invocations = 1;
+	ctx.date_mode.type = DATE_NORMAL;
+	ctx.abbrev = DEFAULT_ABBREV;
+	ctx.describe_status = &describe_status;
+	args.pretty_ctx = &ctx;
 	args.repo = repo;
 	args.prefix = prefix;
 	string_list_init(&args.extra_files, 1);

archive.h

@@ -5,6 +5,7 @@
 #include "pathspec.h"
 
 struct repository;
+struct pretty_print_context;
 
 struct archiver_args {
 	struct repository *repo;
@@ -22,6 +23,7 @@ struct archiver_args {
 	unsigned int convert : 1;
 	int compression_level;
 	struct string_list extra_files;
+	struct pretty_print_context *pretty_ctx;
 };
 
 /* main api */

pretty.c

@@ -12,6 +12,7 @@
 #include "reflog-walk.h"
 #include "gpg-interface.h"
 #include "trailer.h"
+#include "run-command.h"
 
 static char *user_format;
 static struct cmt_fmt_map {
@@ -1206,6 +1207,34 @@ int format_set_trailers_options(struct process_trailer_options *opts,
 	return 0;
 }
 
+static size_t parse_describe_args(const char *start, struct strvec *args)
+{
+	const char *options[] = { "match", "exclude" };
+	const char *arg = start;
+
+	for (;;) {
+		const char *matched = NULL;
+		const char *argval;
+		size_t arglen = 0;
+		int i;
+
+		for (i = 0; i < ARRAY_SIZE(options); i++) {
+			if (match_placeholder_arg_value(arg, options[i], &arg,
+							&argval, &arglen)) {
+				matched = options[i];
+				break;
+			}
+		}
+		if (!matched)
+			break;
+
+		if (!arglen)
+			return 0;
+		strvec_pushf(args, "--%s=%.*s", matched, (int)arglen, argval);
+	}
+	return arg - start;
+}
+
 static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
 				const char *placeholder,
 				void *context)
@@ -1271,6 +1300,41 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
 		return parse_padding_placeholder(placeholder, c);
 	}
 
+	if (skip_prefix(placeholder, "(describe", &arg)) {
+		struct child_process cmd = CHILD_PROCESS_INIT;
+		struct strbuf out = STRBUF_INIT;
+		struct strbuf err = STRBUF_INIT;
+		struct pretty_print_describe_status *describe_status;
+
+		describe_status = c->pretty_ctx->describe_status;
+		if (describe_status) {
+			if (!describe_status->max_invocations)
+				return 0;
+			describe_status->max_invocations--;
+		}
+
+		cmd.git_cmd = 1;
+		strvec_push(&cmd.args, "describe");
+
+		if (*arg == ':') {
+			arg++;
+			arg += parse_describe_args(arg, &cmd.args);
+		}
+
+		if (*arg != ')') {
+			child_process_clear(&cmd);
+			return 0;
+		}
+
+		strvec_push(&cmd.args, oid_to_hex(&commit->object.oid));
+		pipe_command(&cmd, NULL, 0, &out, 0, &err, 0);
+		strbuf_rtrim(&out);
+		strbuf_addbuf(sb, &out);
+		strbuf_release(&out);
+		strbuf_release(&err);
+		return arg - placeholder + 1;
+	}
+
 	/* these depend on the commit */
 	if (!commit->object.parsed)
 		parse_object(the_repository, &commit->object.oid);

pretty.h

@@ -24,6 +24,10 @@ enum cmit_fmt {
 	CMIT_FMT_UNSPECIFIED
 };
 
+struct pretty_print_describe_status {
+	unsigned int max_invocations;
+};
+
 struct pretty_print_context {
 	/*
 	 * Callers should tweak these to change the behavior of pp_* functions.
@@ -45,6 +49,7 @@ struct pretty_print_context {
 	int color;
 	struct ident_split *from_ident;
 	unsigned encode_email_headers:1;
+	struct pretty_print_describe_status *describe_status;
 
 	/*
 	 * Fields below here are manipulated internally by pp_* functions and

t/t4205-log-pretty-formats.sh

@@ -962,4 +962,39 @@ test_expect_success 'log --pretty=reference is colored appropriately' '
 	test_cmp expect actual
 '
 
+test_expect_success '%(describe) vs git describe' '
+	git log --format="%H" | while read hash
+	do
+		if desc=$(git describe $hash)
+		then
+			: >expect-contains-good
+		else
+			: >expect-contains-bad
+		fi &&
+		echo "$hash $desc"
+	done >expect &&
+	test_path_exists expect-contains-good &&
+	test_path_exists expect-contains-bad &&
+
+	git log --format="%H %(describe)" >actual 2>err &&
+	test_cmp expect actual &&
+	test_must_be_empty err
+'
+
+test_expect_success '%(describe:match=...) vs git describe --match ...' '
+	test_when_finished "git tag -d tag-match" &&
+	git tag -a -m tagged tag-match&&
+	git describe --match "*-match" >expect &&
+	git log -1 --format="%(describe:match=*-match)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '%(describe:exclude=...) vs git describe --exclude ...' '
+	test_when_finished "git tag -d tag-exclude" &&
+	git tag -a -m tagged tag-exclude &&
+	git describe --exclude "*-exclude" >expect &&
+	git log -1 --format="%(describe:exclude=*-exclude)" >actual &&
+	test_cmp expect actual
+'
+
 test_done

t/t5001-archive-attr.sh

@@ -128,4 +128,18 @@ test_expect_success 'export-subst' '
 	test_cmp substfile2 archive/substfile2
 '
 
+test_expect_success 'export-subst expands %(describe) once' '
+	echo "\$Format:%(describe)\$" >substfile3 &&
+	echo "\$Format:%(describe)\$" >>substfile3 &&
+	echo "\$Format:%(describe)${LF}%(describe)\$" >substfile4 &&
+	git add substfile[34] &&
+	git commit -m export-subst-describe &&
+	git tag -m export-subst-describe export-subst-describe &&
+	git archive HEAD >archive-describe.tar &&
+	extract_tar_to_dir archive-describe &&
+	desc=$(git describe) &&
+	grep -F "$desc" archive-describe/substfile[34] >substituted &&
+	test_line_count = 1 substituted
+'
+
 test_done