fixup! http: add an "auto" mode for http.emptyauth

Note: we keep a "black list" of authentication methods for which we do
not want to enable http.emptyAuth automatically. A white list would be
nicer, but less robust, as we want to support linking to several cURL
versions and the list of authentication methods (as well as their names)
changed over time.

[jes: actually added the "auto" handling, excluded Digest, too]

This fixes #1034

Signed-off-by: Johannes Schindelin <[email protected]>

http.c

@@ -334,7 +334,10 @@ static int http_options(const char *var, const char *value, void *cb)
 		return git_config_string(&user_agent, var, value);
 
 	if (!strcmp("http.emptyauth", var)) {
-		curl_empty_auth = git_config_bool(var, value);
+		if (value && !strcmp("auto", value))
+			curl_empty_auth = -1;
+		else
+			curl_empty_auth = git_config_bool(var, value);
 		return 0;
 	}
 
@@ -385,29 +388,37 @@ static int http_options(const char *var, const char *value, void *cb)
 
 static int curl_empty_auth_enabled(void)
 {
-	if (curl_empty_auth < 0) {
-#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
-		/*
-		 * In the automatic case, kick in the empty-auth
-		 * hack as long as we would potentially try some
-		 * method more exotic than "Basic".
-		 *
-		 * But only do so when this is _not_ our initial
-		 * request, as we would not then yet know what
-		 * methods are available.
-		 */
-		return http_auth_methods_restricted &&
-		       http_auth_methods != CURLAUTH_BASIC;
+	if (curl_empty_auth >= 0)
+		return curl_empty_auth;
+
+#ifndef LIBCURL_CAN_HANDLE_AUTH_ANY
+	/*
+	 * Our libcurl is too old to do AUTH_ANY in the first place;
+	 * just default to turning the feature off.
+	 */
 #else
-		/*
-		 * Our libcurl is too old to do AUTH_ANY in the first place;
-		 * just default to turning the feature off.
-		 */
-		return 0;
+	/*
+	 * In the automatic case, kick in the empty-auth
+	 * hack as long as we would potentially try some
+	 * method more exotic than "Basic".
+	 *
+	 * But only do this when this is our second or
+	 * subsequent * request, as by then we know what
+	 * methods are available.
+	 */
+	if (http_auth_methods_restricted)
+		switch (http_auth_methods) {
+		case CURLAUTH_BASIC:
+		case CURLAUTH_DIGEST:
+#ifdef CURLAUTH_DIGEST_IE
+		case CURLAUTH_DIGEST_IE:
 #endif
-	}
-
-	return curl_empty_auth;
+			return 0;
+		default:
+			return 1;
+		}
+#endif
+	return 0;
 }
 
 static void init_curl_http_auth(CURL *result)