Add option to verify gyb-generated files

Author: ahoppen

build-script.py

@@ -92,28 +92,30 @@ def check_rsync():
             fatal_error('Error: Could not find rsync.')
 
 
-def generate_gyb_files(verbose, add_source_locations):
+def generate_gyb_files(verbose, add_source_locations, destination=None):
     print('** Generating gyb Files **')
 
     check_gyb_exec()
     check_rsync()
 
     swiftsyntax_sources_dir = PACKAGE_DIR + '/Sources/SwiftSyntax'
     temp_files_dir = tempfile.gettempdir()
-    generated_files_dir = swiftsyntax_sources_dir + '/gyb_generated'
+
+    if destination is None:
+        destination = swiftsyntax_sources_dir + '/gyb_generated'
 
     if not os.path.exists(temp_files_dir):
         os.makedirs(temp_files_dir)
-    if not os.path.exists(generated_files_dir):
-        os.makedirs(generated_files_dir)
+    if not os.path.exists(destination):
+        os.makedirs(destination)
 
     # Clear any *.swift files that are relics from the previous run.
-    for previous_gyb_gen_file in os.listdir(generated_files_dir):
+    for previous_gyb_gen_file in os.listdir(destination):
       if previous_gyb_gen_file.endswith('.swift'):
         gyb_file = os.path.join(swiftsyntax_sources_dir,
                                 previous_gyb_gen_file + '.gyb')
         if not os.path.exists(gyb_file):
-          check_call(['rm', previous_gyb_gen_file], cwd=generated_files_dir,
+          check_call(['rm', previous_gyb_gen_file], cwd=destination,
                      verbose=verbose)
 
     # Generate the new .swift files in a temporary directory and only copy them
@@ -145,7 +147,7 @@ def generate_gyb_files(verbose, add_source_locations):
         check_call(['rsync'] +
                    ['--checksum'] +
                    [temp_files_dir + '/' + output_file_name] +
-                   [generated_files_dir + '/' + output_file_name],
+                   [destination + '/' + output_file_name],
                    verbose=verbose)
 
     print('Done Generating gyb Files')
@@ -221,6 +223,24 @@ def build(self, product_name, module_group_path=''):
 
 
 ## Testing
+def verify_generated_files(verbose):
+    user_generated_dir = os.path.join(PACKAGE_DIR, 'Sources', 'SwiftSyntax',
+                                      'gyb_generated')
+    self_generated_dir = tempfile.mkdtemp()
+    generate_gyb_files(verbose=verbose,
+                       add_source_locations=False,
+                       destination=self_generated_dir)
+
+    command = [
+        'diff', '-r',
+        '-x', '.*', # Exclude dot files like .DS_Store
+        '--context=0',
+        self_generated_dir,
+        user_generated_dir,
+    ]
+    check_call(command)
+
+
 def run_tests(swift_test_exec, build_dir, parser_header_dir, parser_lib_dir,
               release, swift_build_exec, filecheck_exec, swiftc_exec, verbose):
     print('** Running SwiftSyntax Tests **')
@@ -501,6 +521,11 @@ def main():
       Path to the FileCheck executable that was built as part of the LLVM
       repository. If not specified, it will be looked up from PATH.
       ''')
+    testing_group.add_argument('--verify-generated-files', action='store_true',
+                               help='''
+      Instead of generating files using gyb, verify that the files which
+      already exist match the ones that would be generated by this script.
+      ''')
 
     args = parser.parse_args(sys.argv[1:])
 
@@ -521,20 +546,30 @@ def main():
         sys.exit(0)
 
     try:
-        generate_gyb_files(verbose=args.verbose,
-                           add_source_locations=args.add_source_locations)
+        if not args.verify_generated_files:
+            generate_gyb_files(verbose=args.verbose,
+                               add_source_locations=args.add_source_locations)
         # Skip the rest of the build if we should perform degyb only
         if args.degyb_only:
             sys.exit(0)
     except subprocess.CalledProcessError as e:
-        printerr('Error: Generating .gyb files failed')
+        printerr('FAIL: Generating .gyb files failed')
         printerr('Executing: %s' % ' '.join(e.cmd))
         printerr(e.output)
         sys.exit(1)
 
+    if args.verify_generated_files:
+        try:
+            success = verify_generated_files(verbose=args.verbose)
+        except subprocess.CalledProcessError as e:
+            printerr('FAIL: Gyb-generated files committed to repository do '
+                     'not match generated ones. Please re-generate the '
+                     'gyb-files and recommit them.')
+            sys.exit(1)
+
     if args.generate_xcodeproj:
-      xcode_gen(config=args.xcconfig_path)
-      sys.exit(0)
+        xcode_gen(config=args.xcconfig_path)
+        sys.exit(0)
 
     try:
         builder = Builder(swift_build_exec=args.swift_build_exec,
@@ -551,7 +586,7 @@ def main():
         if args.test:
           builder.build('lit-test-helper')
     except subprocess.CalledProcessError as e:
-        printerr('Error: Building SwiftSyntax failed')
+        printerr('FAIL: Building SwiftSyntax failed')
         printerr('Executing: %s' % ' '.join(e.cmd))
         printerr(e.output)
         sys.exit(1)
@@ -574,7 +609,7 @@ def main():
             else:
                 print('** All tests passed **')
         except subprocess.CalledProcessError as e:
-            printerr('Error: Running tests failed')
+            printerr('FAIL: Running tests failed')
             printerr('Executing: %s' % ' '.join(e.cmd))
             printerr(e.output)
             sys.exit(1)