Retire the scripted difftool

It served its purpose, but now we have a builtin difftool. Time for the
Perl script to enjoy Florida.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

.gitignore

@@ -76,7 +76,6 @@
 /git-init-db
 /git-interpret-trailers
 /git-instaweb
-/git-legacy-difftool
 /git-log
 /git-ls-files
 /git-ls-remote

Makefile

@@ -522,7 +522,6 @@ SCRIPT_LIB += git-sh-setup
 SCRIPT_LIB += git-sh-i18n
 
 SCRIPT_PERL += git-add--interactive.perl
-SCRIPT_PERL += git-legacy-difftool.perl
 SCRIPT_PERL += git-archimport.perl
 SCRIPT_PERL += git-cvsexportcommit.perl
 SCRIPT_PERL += git-cvsimport.perl

builtin/difftool.c

@@ -616,30 +616,6 @@ static int run_file_diff(int prompt, const char *prefix,
 	exit(ret);
 }
 
-/*
- * NEEDSWORK: this function can go once the legacy-difftool Perl script is
- * retired.
- *
- * We intentionally avoid reading the config directly here, to avoid messing up
- * the GIT_* environment variables when we need to fall back to exec()ing the
- * Perl script.
- */
-static int use_builtin_difftool(void) {
-	struct child_process cp = CHILD_PROCESS_INIT;
-	struct strbuf out = STRBUF_INIT;
-	int ret;
-
-	argv_array_pushl(&cp.args,
-			 "config", "--bool", "difftool.usebuiltin", NULL);
-	cp.git_cmd = 1;
-	if (capture_command(&cp, &out, 6))
-		return 0;
-	strbuf_trim(&out);
-	ret = !strcmp("true", out.buf);
-	strbuf_release(&out);
-	return ret;
-}
-
 int cmd_difftool(int argc, const char **argv, const char *prefix)
 {
 	int use_gui_tool = 0, dir_diff = 0, prompt = -1, symlinks = 0,
@@ -671,23 +647,6 @@ int cmd_difftool(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
-	/*
-	 * NEEDSWORK: Once the builtin difftool has been tested enough
-	 * and git-legacy-difftool.perl is retired to contrib/, this preamble
-	 * can be removed.
-	 */
-	if (!use_builtin_difftool()) {
-		const char *path = mkpath("%s/git-legacy-difftool",
-					  git_exec_path());
-
-		if (sane_execvp(path, (char **)argv) < 0)
-			die_errno("could not exec %s", path);
-
-		return 0;
-	}
-	prefix = setup_git_directory();
-	trace_repo_setup(prefix);
-	setup_work_tree();
 	/* NEEDSWORK: once we no longer spawn anything, remove this */
 	setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
 	setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);

git.c

@@ -424,12 +424,7 @@ static struct cmd_struct commands[] = {
 	{ "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
 	{ "diff-index", cmd_diff_index, RUN_SETUP },
 	{ "diff-tree", cmd_diff_tree, RUN_SETUP },
-	/*
-	 * NEEDSWORK: Once the redirection to git-legacy-difftool.perl in
-	 * builtin/difftool.c has been removed, this entry should be changed to
-	 * RUN_SETUP | NEED_WORK_TREE
-	 */
-	{ "difftool", cmd_difftool },
+	{ "difftool", cmd_difftool, RUN_SETUP | NEED_WORK_TREE },
 	{ "fast-export", cmd_fast_export, RUN_SETUP },
 	{ "fetch", cmd_fetch, RUN_SETUP },
 	{ "fetch-pack", cmd_fetch_pack, RUN_SETUP },