[PATCH v3 15/17] trailer: set author and committer env variables

@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "run-command.h"
+#include "argv-array.h"
 /*
  * Copyright (c) 2013 Christian Couder <chriscool@tuxfamily.org>
  */

@@ -415,14 +416,40 @@ static int read_from_command(struct child_process *cp, struct strbuf *buf)
 	return 0;
 }
 
+static void setup_ac_env(struct argv_array *env, const char *ac_name, const char *ac_mail, const char *(*read)(int))
+{
+	if (!getenv(ac_name) || !getenv(ac_mail)) {
+		struct ident_split ident;
+		const char *namebuf, *mailbuf;
+		int namelen, maillen;
+		const char *ac_info = read(IDENT_NO_DATE);
+
+		if (split_ident_line(&ident, ac_info, strlen(ac_info)))
+			return;
+
+		namelen = ident.name_end - ident.name_begin;
+		namebuf = ident.name_begin;
+
+		maillen = ident.mail_end - ident.mail_begin;
+		mailbuf = ident.mail_begin;
+
+		argv_array_pushf(env, "%s=%.*s", ac_name, namelen, namebuf);
+		argv_array_pushf(env, "%s=%.*s", ac_mail, maillen, mailbuf);
+	}
+}
+
 static const char *apply_command(const char *command, const char *arg)
 {
+	struct argv_array env = ARGV_ARRAY_INIT;
 	struct strbuf cmd = STRBUF_INIT;
 	struct strbuf buf = STRBUF_INIT;
 	struct child_process cp;
 	const char *argv[] = {NULL, NULL};
 	const char *result = "";
 
+	setup_ac_env(&env, "GIT_AUTHOR_NAME", "GIT_AUTHOR_EMAIL", git_author_info);
+	setup_ac_env(&env, "GIT_COMMITTER_NAME", "GIT_COMMITTER_EMAIL", git_committer_info);
+
 	strbuf_addstr(&cmd, command);
 	if (arg)
 		strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);

@@ -430,7 +457,7 @@ static const char *apply_command(const char *command, const char *arg)
 	argv[0] = cmd.buf;
 	memset(&cp, 0, sizeof(cp));
 	cp.argv = argv;
-	cp.env = local_repo_env;
+	cp.env = env.argv;
 	cp.no_stdin = 1;
 	cp.out = -1;
 	cp.use_shell = 1;

@@ -441,6 +468,7 @@ static const char *apply_command(const char *command, const char *arg)
 		result = strbuf_detach(&buf, NULL);
 
 	strbuf_release(&cmd);
+	argv_array_clear(&env);
 	return result;
 }