use the git config file for reading origin_url

src/resolvers/git.cr

@@ -1,4 +1,5 @@
 require "uri"
+require "ini"
 require "./resolver"
 require "../versions"
 require "../logger"
@@ -369,8 +370,16 @@ module Shards
       false
     end
 
-    private def origin_url
-      @origin_url ||= capture("git -C #{local_path} config --get remote.origin.url").strip
+    private def origin_url : String?
+      @origin_url ||= begin
+        git_config_file = File.join(local_path, "config")
+
+        return nil unless File.exists?(git_config_file)
+
+        config = INI.parse(File.read(git_config_file))
+
+        return config.dig("remote \"origin\"", "url")
+      end
     end
 
     # Returns whether origin URLs have differing hosts and/or paths.
@@ -387,14 +396,14 @@ module Shards
         return true
       end
 
-      origin_parsed = parse_uri(origin_url)
-      git_parsed = parse_uri(git_url)
+      origin_parsed = parse_uri(origin_url.not_nil!)
+      git_parsed = parse_uri(git_url.not_nil!)
 
       (origin_parsed.host != git_parsed.host) || (origin_parsed.path != git_parsed.path)
     end
 
     # Parses a URI string, with additional support for ssh+git URI schemes.
-    private def parse_uri(raw_uri)
+    private def parse_uri(raw_uri : String)
       # Need to check for file URIs early, otherwise generic parsing will fail on a colon.
       if (path = raw_uri.lchop?("file://"))
         return URI.new(scheme: "file", path: path)