Re: git should not use a default user.email config value

[Jeff King <peff@peff.net>]

On Tue, Aug 13, 2013 at 07:46:35AM -0400, Jeff King wrote:

> The only downside I can think of is that we might want to use the
> subsection in "include.SUBSECTION.*" for some other limiting conditions
> (e.g., "only include this config when running version >= X.Y", or even
> "include only when environment variable FOO is true").
> 
> I guess we could do something like:
> 
>   [include "repo:...your regex here..."]
>     path = .gitconfig-only-for-some-repos
>   [include "env:USE_MY_MAGIC_CONFIG"]
>     path = .gitconfig-only-when-magic-env-set
> 
> Adding the "repo:" prefix for this repo-dir matching is pretty trivial.
> Adding a similar env-matching is only slightly less trivial; but does
> anybody actually want it?

Here it is with the "repo:" prefix, if you want to build on that.

Adding the "env" spec is as easy as doing this on top:


	diff --git a/config.c b/config.c
	index f1ca6fa..64ba141 100644
	--- a/config.c
	+++ b/config.c
	@@ -150,6 +150,8 @@ static int match_config_include(const char *spec)
	 	const char *val;
	 	if ((val = skip_prefix(spec, "repo:")))
	 		return match_repo_path(val);
	+	if ((val = skip_prefix(spec, "env:")))
	+		return git_env_bool(val, 0);
	 
	 	/* Unknown specs are considered "no match". */
	 	return 0;

---
diff --git a/config.c b/config.c
index e13a7b6..f1ca6fa 100644
--- a/config.c
+++ b/config.c
@@ -119,10 +119,55 @@ int git_config_include(const char *var, const char *value, void *data)
 	return ret;
 }
 
+static NORETURN void die_bad_regex(int err, regex_t *re)
+{
+	char errbuf[1024];
+	regerror(err, re, errbuf, sizeof(errbuf));
+	if (cf && cf->name)
+		die("bad regex (at %s:%d): %s", cf->name, cf->linenr, errbuf);
+	else
+		die("bad regex: %s", errbuf);
+}
+
+static int match_repo_path(const char *re_str)
+{
+	regex_t re;
+	int ret;
+	const char *repo_path;
+
+	ret = regcomp(&re, re_str, REG_EXTENDED);
+	if (ret)
+		die_bad_regex(ret, &re);
+
+	repo_path = absolute_path(get_git_dir());
+	ret = regexec(&re, repo_path, 0, NULL, 0);
+	regfree(&re);
+	return !ret;
+}
+
+static int match_config_include(const char *spec)
+{
+	const char *val;
+	if ((val = skip_prefix(spec, "repo:")))
+		return match_repo_path(val);
+
+	/* Unknown specs are considered "no match". */
+	return 0;
+}
+
+static int match_config_include_mem(const char *spec, int spec_len)
+{
+	char *spec_str = xmemdupz(spec, spec_len);
+	int ret = match_config_include(spec_str);
+	free(spec_str);
+	return ret;
+}
+
 int git_config_include(const char *var, const char *value, void *data)
 {
 	struct config_include_data *inc = data;
-	const char *type;
+	const char *match, *type;
+	int match_len;
 	int ret;
 
 	/*
@@ -133,8 +178,9 @@ int git_config_include(const char *var, const char *value, void *data)
 	if (ret < 0)
 		return ret;
 
-	type = skip_prefix(var, "include.");
-	if (!type)
+	if (parse_config_key(var, "include", &match, &match_len, &type))
+		return ret;
+	if (match && !match_config_include_mem(match, match_len))
 		return ret;
 
 	if (!strcmp(type, "path"))