Strict type Dependabot::Bundler::GemspecFinder (#10004)

* Strict type Dependabot::Bundler::GemspecFinder.

* Strict type Dependabot::Bundler::GemspecFinder.

bundler/lib/dependabot/bundler/file_fetcher/gemspec_finder.rb

@@ -1,32 +1,39 @@
-# typed: true
+# typed: strict
 # frozen_string_literal: true
 
 require "pathname"
 require "parser/current"
 require "dependabot/bundler/file_fetcher"
 require "dependabot/errors"
+require "sorbet-runtime"
 
 module Dependabot
   module Bundler
     class FileFetcher
       # Finds the directories of any gemspecs declared using `gemspec` in the
       # passed Gemfile.
       class GemspecFinder
+        extend T::Sig
+
+        sig { params(gemfile: Dependabot::DependencyFile).void }
         def initialize(gemfile:)
           @gemfile = gemfile
         end
 
+        sig { returns(T::Array[String]) }
         def gemspec_directories
-          ast = Parser::CurrentRuby.parse(gemfile.content)
+          ast = Parser::CurrentRuby.parse(T.must(gemfile).content)
           find_gemspec_paths(ast)
         rescue Parser::SyntaxError
-          raise Dependabot::DependencyFileNotParseable, gemfile.path
+          raise Dependabot::DependencyFileNotParseable, T.must(gemfile).path
         end
 
         private
 
+        sig { returns(T.nilable(Dependabot::DependencyFile)) }
         attr_reader :gemfile
 
+        sig { params(node: T.untyped).returns(T::Array[T.untyped]) }
         def find_gemspec_paths(node)
           return [] unless node.is_a?(Parser::AST::Node)
 
@@ -35,7 +42,7 @@ def find_gemspec_paths(node)
             return [clean_path(".")] unless path_node
 
             unless path_node.type == :str
-              path = gemfile.path
+              path = T.must(gemfile).path
               msg = "Dependabot only supports uninterpolated string arguments " \
                     "to gemspec. Got " \
                     "`#{path_node.loc.expression.source}`"
@@ -51,18 +58,21 @@ def find_gemspec_paths(node)
           end
         end
 
+        sig { returns(T.nilable(String)) }
         def current_dir
-          @current_dir ||= gemfile.name.rpartition("/").first
+          @current_dir ||= T.let(gemfile&.name&.rpartition("/")&.first, T.nilable(String))
           @current_dir = nil if @current_dir == ""
           @current_dir
         end
 
+        sig { params(node: Parser::AST::Node).returns(T::Boolean) }
         def declares_gemspec_dependency?(node)
           return false unless node.is_a?(Parser::AST::Node)
 
           node.children[1] == :gemspec
         end
 
+        sig { params(path: String).returns(Pathname) }
         def clean_path(path)
           if Pathname.new(path).absolute?
             base_path = Pathname.new(File.expand_path(Dir.pwd))
@@ -72,6 +82,7 @@ def clean_path(path)
           Pathname.new(path).cleanpath
         end
 
+        sig { params(node: Parser::AST::Node).returns(T.nilable(Parser::AST::Node)) }
         def path_node_for_gem_declaration(node)
           return unless node.children.last.is_a?(Parser::AST::Node)
           return unless node.children.last.type == :hash
@@ -87,6 +98,7 @@ def path_node_for_gem_declaration(node)
           path_hash_pair.children.last
         end
 
+        sig { params(node: Parser::AST::Node).returns(Symbol) }
         def key_from_hash_pair(node)
           node.children.first.children.first.to_sym
         end