Add --local to not fetch remote repositories

Uses the local cahe as is. Speeds up installing shards when we know
the cache is up to date.

It will fail when the repository wasn't cloned into the cache, and
it won't find new releases until the cache is updated by running the
install or update commands without --local.

Author: ysbaddaden

src/cli.cr

@@ -29,6 +29,7 @@ module Shards
       opts.on("--no-color", "Disable colored output.") { self.colors = false }
       opts.on("--version", "Prints the `shards` version.") { puts self.version_string; exit }
       opts.on("--production", "Run in release mode. No development dependencies and strict sync between shard.yml and shard.lock.") { self.production = true }
+      opts.on("--local", "Don't update remote repositories, use the local cache only.") { self.local = true }
       opts.on("-v", "--verbose", "Increases the log verbosity, printing all debug statements.") { self.logger.level = Logger::Severity::DEBUG }
       opts.on("-q", "--quiet", "Decreases the log verbosity, printing only warnings and errors.") { self.logger.level = Logger::Severity::WARN }
       opts.on("-h", "--help", "Prints usage synopsis.") { self.display_help_and_exit(opts) }

src/config.cr

@@ -71,12 +71,6 @@ module Shards
   def self.bin_path=(@@bin_path : String)
   end
 
-  @@production = false
-
-  def self.production?
-    @@production
-  end
-
-  def self.production=(@@production)
-  end
+  class_property? production = false
+  class_property? local = false
 end

src/resolvers/git.cr

@@ -172,7 +172,7 @@ module Shards
         @updated_cache = false
       end
 
-      return if @updated_cache
+      return if Shards.local? || @updated_cache
       Shards.logger.info "Fetching #{git_url}"
 
       if cloned_repository?
@@ -234,6 +234,10 @@ module Shards
     end
 
     private def run(command, path = local_path, capture = false)
+      if Shards.local? && !Dir.exists?(path)
+        dependency_name = File.basename(path, ".git")
+        raise Error.new("Missing repository cache for #{dependency_name.inspect}. Please run without --local to fetch it.")
+      end
       Dir.cd(path) do
         run_in_current_folder(command, capture)
       end

test/integration/update_test.cr

@@ -201,4 +201,32 @@ class UpdateCommandTest < Minitest::Test
     assert File.exists?(foo), "Expected to have installed bin/foo executable"
     assert_equal "FOO\n", `#{foo}`
   end
+
+  def test_doesnt_update_local_cache
+    metadata = {
+      dependencies: { local_cache: "*" },
+    }
+
+    with_shard(metadata) do
+      # error: dependency isn't in local cache
+      ex = assert_raises(FailedCommand) { run("shards install --local --no-color") }
+      assert_match %(E: Missing repository cache for "local_cache".), ex.stdout
+    end
+
+    # re-run without --local to install the dependency:
+    create_git_repository "local_cache", "1.0", "2.0"
+    with_shard(metadata) { run("shards install") }
+    assert_locked "local_cache", "2.0"
+
+    # create a new release:
+    create_git_release "local_cache", "3.0"
+
+    # re-run with --local, which won't find the new release:
+    with_shard(metadata) { run("shards update --local") }
+    assert_locked "local_cache", "2.0"
+
+    # run again without --local, which will find & install the new release:
+    with_shard(metadata) { run("shards update") }
+    assert_locked "local_cache", "3.0"
+  end
 end