Merge branch 'jc/war-on-dashed-git' into seen

The first step to remove on-disk binaries for built-in subcommands
by soliciting objections.

* jc/war-on-dashed-git:
  git: catch an attempt to run "git-foo"

command-list.txt

@@ -39,6 +39,9 @@
 # mainporcelain commands are completable so you don't need this
 # attribute.
 #
+# "onpath" attribute is used to mark that the command MUST appear
+# on $PATH (typically in /usr/bin) due to protocol requirement.
+#
 # As part of the Git man page list, the man(5/7) guides are also
 # specified here, which can only have "guide" attribute and nothing
 # else.
@@ -145,7 +148,7 @@ git-quiltimport                         foreignscminterface
 git-range-diff                          mainporcelain
 git-read-tree                           plumbingmanipulators
 git-rebase                              mainporcelain           history
-git-receive-pack                        synchelpers
+git-receive-pack                        synchelpers        onpath
 git-reflog                              ancillarymanipulators           complete
 git-remote                              ancillarymanipulators           complete
 git-repack                              ancillarymanipulators           complete
@@ -160,7 +163,7 @@ git-rev-parse                           plumbinginterrogators
 git-rm                                  mainporcelain           worktree
 git-send-email                          foreignscminterface             complete
 git-send-pack                           synchingrepositories
-git-shell                               synchelpers
+git-shell                               synchelpers        onpath
 git-shortlog                            mainporcelain
 git-show                                mainporcelain           info
 git-show-branch                         ancillaryinterrogators          complete
@@ -183,8 +186,8 @@ git-unpack-objects                      plumbingmanipulators
 git-update-index                        plumbingmanipulators
 git-update-ref                          plumbingmanipulators
 git-update-server-info                  synchingrepositories
-git-upload-archive                      synchelpers
-git-upload-pack                         synchelpers
+git-upload-archive                      synchelpers        onpath
+git-upload-pack                         synchelpers        onpath
 git-var                                 plumbinginterrogators
 git-verify-commit                       ancillaryinterrogators
 git-verify-pack                         plumbinginterrogators

git.c

@@ -872,6 +872,8 @@ int cmd_main(int argc, const char **argv)
 	 * that one cannot handle it.
 	 */
 	if (skip_prefix(cmd, "git-", &cmd)) {
+		warn_on_dashed_git(argv[0]);
+
 		argv[0] = cmd;
 		handle_builtin(argc, argv);
 		die(_("cannot handle %s as a builtin"), cmd);

help.c

@@ -722,3 +722,37 @@ NORETURN void help_unknown_ref(const char *ref, const char *cmd,
 	string_list_clear(&suggested_refs, 0);
 	exit(1);
 }
+
+static struct cmdname_help *find_cmdname_help(const char *name)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(command_list); i++) {
+		if (!strcmp(command_list[i].name, name))
+			return &command_list[i];
+	}
+	return NULL;
+}
+
+void warn_on_dashed_git(const char *cmd)
+{
+	struct cmdname_help *cmdname;
+	static const char *still_in_use_var = "GIT_I_STILL_USE_DASHED_GIT";
+	static const char *still_in_use_msg =
+		N_("Use of '%s' in the dashed-form is nominated for removal.\n"
+		   "If you still use it, export '%s=true'\n"
+		   "and send an e-mail to <git@vger.kernel.org>\n"
+		   "to let us know and stop our removal plan.  Thanks.\n");
+
+	if (!cmd)
+		return; /* git-help is OK */
+
+	cmdname = find_cmdname_help(cmd);
+	if (cmdname && (cmdname->category & CAT_onpath))
+		return; /* git-upload-pack and friends are OK */
+
+	if (!git_env_bool(still_in_use_var, 0)) {
+		fprintf(stderr, _(still_in_use_msg), cmd, still_in_use_var);
+		exit(1);
+	}
+}

help.h

@@ -46,6 +46,9 @@ void get_version_info(struct strbuf *buf, int show_build_options);
  */
 NORETURN void help_unknown_ref(const char *ref, const char *cmd, const char *error);
 
+/* When the cmd_main() sees "git-foo", check if the user intended */
+void warn_on_dashed_git(const char *);
+
 static inline void list_config_item(struct string_list *list,
 				    const char *prefix,
 				    const char *str)