Merge pull request #49 from apainintheneck/add-statup-stats-command

Add statup stats command

.github/workflows/integration_tests.yml

@@ -40,3 +40,5 @@ jobs:
     - run: rake test:generate-api-diff
 
     - run: rake test:service-diff
+
+    - run: rake test:startup-stats

README.md

@@ -102,6 +102,26 @@ running other brew commands simultaneously.
   -h, --help                       Show this message.
 ```
 
+### brew startup-stats
+
+```
+Usage: brew startup-stats [option]
+
+Get information about the state of brew at the time a command is called. This
+includes loaded constants, requires and other such information.
+
+      --defined                    Check if a constant is defined.
+      --require                    Diagnostics about a single require statement.
+      --list-requires              List all requires made before this command
+                                   was run.
+      --list-constants             List all constants loaded before this command
+                                   was run.
+  -d, --debug                      Display any debugging information.
+  -q, --quiet                      Make some output more quiet.
+  -v, --verbose                    Make some output more verbose.
+  -h, --help                       Show this message.
+```
+
 ## Development
 
 Linting and readme checks are run on each pull request while integration tests are only run weekly.

Rakefile

@@ -112,12 +112,17 @@ namespace "test" do
     end
   end
 
+  task :"startup-stats" do
+    cmd "brew", "startup-stats", "--require", "tap"
+  end
+
   task :all do
     %w[
       test:api-readall-test
       test:branch-compare
       test:generate-api-diff
       test:service-diff
+      test:startup-stats
     ].each_with_index do |task, index|
       puts "--------------------" if index.positive?
       Rake::Task[task].invoke
@@ -148,7 +153,7 @@ task :"missing-tests" do
       Missing integration tests for the following commands:
       #{missing_test_list}
 
-      Add tests to the #{INTEGRATON_TESTS} file.
+      Add tests to the #{INTEGRATION_TESTS_FILE} file.
     EOS
   end
 end

cmd/startup-stats.rb

@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+module Homebrew
+  module Cmd
+    class StartupStats < AbstractCommand
+      cmd_args do
+        usage_banner "`startup-stats` [<option>]"
+        description <<~EOS
+          Get information about the state of brew at the time a command is called.
+          This includes loaded constants, requires and other such information.
+        EOS
+
+        flag "--defined=", description: "Check if a constant is defined."
+        flag "--require=", description: "Diagnostics about a single require statement."
+        switch "--list-requires", description: "List all requires made before this command was run."
+        switch "--list-constants", description: "List all constants loaded before this command was run."
+
+        %w[
+          --defined
+          --require
+          --list-requires
+          --list-constants
+        ].combination(2) do |combo|
+          conflicts(*combo)
+        end
+      end
+
+      def run
+        if args.defined
+          puts Object.const_defined?(args.defined)
+        elsif args.require
+          require_diagnostics
+        elsif args.list_requires?
+          puts require_list
+        elsif args.list_constants?
+          puts constant_list
+        else
+          odie "No options provided to the command!"
+        end
+      end
+
+      def require_list
+        $LOADED_FEATURES.sort
+      end
+
+      def constant_list
+        Object.constants.sort
+      end
+
+      def require_diagnostics
+        odie "'brew' cannot be required directly." if args.require == "brew"
+
+        begin
+          before_require_list = require_list
+          before_constant_list = constant_list
+
+          hash = benchmark { require args.require }
+          hash => { result:, elapsed_seconds: }
+
+          new_require_list = require_list - before_require_list
+          new_constant_list = constant_list - before_constant_list
+
+          if result
+            oh1 "require '#{args.require}'"
+            ohai "elapsed seconds"
+            puts "- #{elapsed_seconds}"
+            if new_require_list.any?
+              puts
+              ohai "new requires"
+              new_require_list.each { puts "- #{_1}" }
+            end
+            if new_constant_list.any?
+              puts
+              ohai "new constants"
+              new_constant_list.each { puts "- #{_1}" }
+            end
+          else
+            odie "'#{args.require}' has already been required."
+          end
+        rescue LoadError => e
+          odie e.to_s
+        end
+      end
+
+      def benchmark
+        start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+        result = yield
+        end_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+        elapsed_seconds = end_time - start_time
+        { result:, elapsed_seconds: }
+      end
+    end
+  end
+end