Parse output from xcodebuild to make it easier to spot problems with non-incremental builds.

dart/tools/build.py

 #!/usr/bin/env python
 #
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 #
 
 import optparse
 import os
 import shutil
@@ skipping 206 matching lines @@
     with open(build_cookie_path, 'w') as f:
       f.write(target_os)
     GClientRunHooks()
 
 
 def CurrentDirectoryBaseName():
   """Returns the name of the current directory"""
   return os.path.relpath(os.curdir, start=os.pardir)
 
 
-def ParseXcodebuild(args):
+def FilterEmptyXcodebuildSections(process):
   """
-  Run xcodebuild and returns the process object.
-  Output is parsed to filter out build actions that had no output.
+  Filter output from xcodebuild so empty sections are less verbose.
+
+  The output from xcodebuild looks like this:
+
+Build settings from command line:
+    SYMROOT = .../xcodebuild
+
+=== BUILD AGGREGATE TARGET samples OF PROJECT dart WITH CONFIGURATION ReleaseIA32 ===

[kustermann, 2013/04/05 15:31:01]

You could abbreviate these lines with '...' so we don't hit the 80 character
limit.

[ahe, 2013/04/05 15:45:44]

Done.

+Check dependencies
+
+
+=== BUILD AGGREGATE TARGET upload_sdk OF PROJECT dart WITH CONFIGURATION ReleaseIA32 ===
+Check dependencies
+
+PhaseScriptExecution "Action \"upload_sdk_py\"" xcodebuild/dart.build/ReleaseIA32/upload_sdk.build/Script-822253BD7234630D393BA4AC.sh
+    cd ...
+    /bin/sh -c .../xcodebuild/dart.build/ReleaseIA32/upload_sdk.build/Script-822253BD7234630D393BA4AC.sh
+
+
+** BUILD SUCCEEDED **
+
   """
 
   def is_empty_chunk(chunk):
     empty_chunk = ['Check dependencies', '', '']
     return not chunk or (len(chunk) == 4 and chunk[1:] == empty_chunk)
 
-  process = subprocess.Popen(args,
-                             bufsize=0,
-                             stdin=None,
-                             stdout=subprocess.PIPE,
-                             stderr=subprocess.STDOUT)
+  def unbuffered(callable):
+    # Use iter to disable buffering in for-in.
+    return iter(callable, b'')

[kustermann, 2013/04/05 15:31:01]

The 'b' should not be necessary here.

[ahe, 2013/04/05 15:45:44]

Done.

+
   section = None
   chunk = []
-  for line in process.stdout:
+  # Is stdout a terminal?
+  isatty = sys.stdout.isatty()
+  for line in unbuffered(process.stdout.readline):
     line = line.rstrip()
     if line.startswith('=== BUILD ') or line.startswith('** BUILD '):
       if not is_empty_chunk(chunk):
         print '\n'.join(chunk)
       section = line
+      if isatty:
+        # If stdout is a terminal, emit "progress" information.
+        print '%s[2K%s\r' % (chr(27), section),
       chunk = []
     if not section:
       print line
     else:
       chunk.append(line)
   if not is_empty_chunk(chunk):
     print '\n'.join(chunk)
-  return process
 
 
 def Main():
   utils.ConfigureJava()
   # Parse the options.
   parser = BuildOptions()
   (options, args) = parser.parse_args()
   if not ProcessOptions(options, args):
     parser.print_help()
     return 1
   # Determine which targets to build. By default we build the "all" target.
   if len(args) == 0:
     if HOST_OS == 'macos':
       target = 'All'
     else:
       target = 'all'
   else:
     target = args[0]
 
-  parse_xcodebuild = False
+  filter_xcodebuild_output = False
   # Remember path
   old_path = os.environ['PATH']
   # Build the targets for each requested configuration.
   for target_os in options.os:
     for mode in options.mode:
       for arch in options.arch:
         build_config = utils.GetBuildConf(mode, arch)
         if HOST_OS == 'macos':
-          parse_xcodebuild = True
+          filter_xcodebuild_output = True
           project_file = 'dart.xcodeproj'
           if os.path.exists('dart-%s.gyp' % CurrentDirectoryBaseName()):
             project_file = 'dart-%s.xcodeproj' % CurrentDirectoryBaseName()
           args = ['xcodebuild',
                   '-project',
                   project_file,
                   '-target',
                   target,
                   '-configuration',
                   build_config,
@@ skipping 48 matching lines @@
         toolsOverride = SetTools(arch, toolchainprefix)
         if toolsOverride:
           printToolOverrides = target_os != 'android'
           for k, v in toolsOverride.iteritems():
             args.append(  k + "=" + v)
             if printToolOverrides:
               print k + " = " + v
 
         print ' '.join(args)
         process = None
-        if parse_xcodebuild:
-          process = ParseXcodebuild(args)
+        if filter_xcodebuild_output:
+          process = subprocess.Popen(args,
+                                     stdin=None,
+                                     bufsize=1, # Line buffered.
+                                     stdout=subprocess.PIPE,
+                                     stderr=subprocess.STDOUT)
+          FilterEmptyXcodebuildSections(process)
         else:
           process = subprocess.Popen(args, stdin=None)
         process.wait()
         if process.returncode != 0:
           print "BUILD FAILED"
           return 1
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(Main())