Re: [PATCH v2 2/2] alias: support non-alphanumeric names via subsection syntax

Suggested-by: Jeff King <redacted>
Signed-off-by: Jonatan Holmgren <redacted>
---
 Documentation/config/alias.adoc | 44 +++++++++++++++++++++-----
 alias.c                         | 45 ++++++++++++++++++++++-----
 help.c                          | 12 +++++--
 t/t0014-alias.sh                | 55 +++++++++++++++++++++++++++++++++
 4 files changed, 137 insertions(+), 19 deletions(-)

diff --git a/Documentation/config/alias.adoc b/Documentation/config/alias.adoc
index 80ce17d2de..17a548cd64 100644
--- a/Documentation/config/alias.adoc
+++ b/Documentation/config/alias.adoc

@@ -1,12 +1,40 @@
 alias.*::
+alias.*.command::
+	Command aliases for the linkgit:git[1] command wrapper. Aliases
+	can be defined using two syntaxes:
++
+--
+1. Without a subsection, e.g., `[alias] co = checkout`. The alias
+   name is limited to alphanumeric characters and `-` (the same
+   limitation as configuration variable names), and is matched
+   case-insensitively.
+2. With a subsection, e.g., `[alias "name"] command = value`. The
+   alias name can contain any characters including UTF-8, and is
+   matched case-sensitively as raw bytes.
+--
++
+Examples:
++
+----
+# Without subsection
+[alias]
+    co = checkout
+    st = status
+
+# With subsection (allows UTF-8 and special characters)
+[alias "hämta"]
+    command = fetch
+[alias "gömma"]
+    command = stash
+----
++
+E.g. after defining `alias.last = cat-file commit HEAD`, the invocation
+`git last` is equivalent to `git cat-file commit HEAD`. To avoid
+confusion and troubles with script usage, aliases that
+hide existing Git commands are ignored except for deprecated
+commands.  Arguments are split by
+spaces, the usual shell quoting and escaping are supported.
+A quote pair or a backslash can be used to quote them.
 +
 Note that the first word of an alias does not necessarily have to be a
 command. It can be a command-line option that will be passed into the

diff --git a/alias.c b/alias.c
index c66a6095bb..cfd313ce5d 100644
--- a/alias.c
+++ b/alias.c

@@ -17,21 +17,50 @@ static int config_alias_cb(const char *key, const char *value,
 			   const struct config_context *ctx UNUSED, void *d)
 {
 	struct config_alias_data *data = d;
-	const char *p;
+	const char *subsection, *subkey;
+	size_t subsection_len;
 
-	if (!skip_prefix(key, "alias.", &p))
+	if (parse_config_key(key, "alias", &subsection, &subsection_len,
+			     &subkey) < 0)
 		return 0;
 
+	/*
+	 * Two config syntaxes:
+	 * - alias.name = value        (without subsection, case-insensitive)
+	 * - [alias "name"]
+	 *       command = value       (with subsection, case-sensitive)
+	 */
+	if (subsection) {
+		if (strcmp(subkey, "command"))
+			return 0;

@@ -108,7 +109,7 @@ static void print_command_list(const struct cmdname_help *cmds,
 
 	for (i = 0; cmds[i].name; i++) {
 		if (cmds[i].category & mask) {
-			size_t len = strlen(cmds[i].name);
+			size_t len = utf8_strwidth(cmds[i].name);
 			printf("   %s   ", cmds[i].name);
 			if (longest > len)
 				mput_char(' ', longest - len);

@@ -492,7 +493,7 @@ static void list_all_cmds_help_aliases(int longest)
 	string_list_sort(&alias_list);
 
 	for (i = 0; i < alias_list.nr; i++) {
-		size_t len = strlen(alias_list.items[i].string);
+		size_t len = utf8_strwidth(alias_list.items[i].string);
 		if (longest < len)
 			longest = len;
 	}

@@ -590,8 +591,13 @@ static int git_unknown_cmd_config(const char *var, const char *value,
 
 	/* Also use aliases for command lookup */
 	if (!parse_config_key(var, "alias", &subsection, &subsection_len, &key)) {
-		if (!subsection)
+		if (subsection) {
+			if (!strcmp(key, "command"))
+				add_cmdname(&cfg->aliases, subsection,
+					    subsection_len);
+		} else {
 			add_cmdname(&cfg->aliases, key, strlen(key));
+		}
 	}