completion: add and use --list-cmds=alias

By providing aliases via --list-cmds=, we could simplify command
collection code in the script. We only issue one git command. Before
this patch that is "git config", after it's "git --list-cmds=". In
"git help" completion case we actually reduce one "git" process (for
getting guides) but that call was added in this series so it does not
really count.

A couple of bash functions are removed because they are not needed
anymore. __git_compute_all_commands() and $__git_all_commands stay
because they are still needed for completing pager.* config and
without "alias" group, the result is still cacheable.

There is a slight (good) change in _git_help() with this patch: before
"git help <tab>" shows external commands (as in _not_ part of git) as
well as part of $__git_all_commands. We have finer control over
command listing now and can exclude that because we can't provide a
man page for external commands anyway.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 19 insertions, 2 deletions

diff --git a/alias.c b/alias.c
index e9726ce8c5..a7e4e57130 100644
--- a/alias.c
+++ b/alias.c
@@ -1,10 +1,12 @@
 #include "cache.h"
 #include "alias.h"
 #include "config.h"
+#include "string-list.h"
 
 struct config_alias_data {
 	const char *alias;
 	char *v;
+	struct string_list *list;
 };
 
 static int config_alias_cb(const char *key, const char *value, void *d)
@@ -12,8 +14,16 @@ static int config_alias_cb(const char *key, const char *value, void *d)
 	struct config_alias_data *data = d;
 	const char *p;
 
-	if (skip_prefix(key, "alias.", &p) && !strcasecmp(p, data->alias))
-		return git_config_string((const char **)&data->v, key, value);
+	if (!skip_prefix(key, "alias.", &p))
+		return 0;
+
+	if (data->alias) {
+		if (!strcasecmp(p, data->alias))
+			return git_config_string((const char **)&data->v,
+						 key, value);
+	} else if (data->list) {
+		string_list_append(data->list, p);
+	}
 
 	return 0;
 }
@@ -27,6 +37,13 @@ char *alias_lookup(const char *alias)
 	return data.v;
 }
 
+void list_aliases(struct string_list *list)
+{
+	struct config_alias_data data = { NULL, NULL, list };
+
+	read_early_config(config_alias_cb, &data);
+}
+
 #define SPLIT_CMDLINE_BAD_ENDING 1
 #define SPLIT_CMDLINE_UNCLOSED_QUOTE 2
 static const char *split_cmdline_errors[] = {