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

dart/tools/build.py

Index: dart/tools/build.py
diff --git a/dart/tools/build.py b/dart/tools/build.py
index df6d55fbf784f7d2b4b67fbc30b59f5811b96d24..0af090371713672c9b3f79fa87210853c6198fcb 100755
--- a/dart/tools/build.py
+++ b/dart/tools/build.py
@@ -224,29 +224,52 @@ def CurrentDirectoryBaseName():
   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
@@ -254,7 +277,6 @@ def ParseXcodebuild(args):
       chunk.append(line)
   if not is_empty_chunk(chunk):
     print '\n'.join(chunk)
-  return process
 
 
 def Main():
@@ -274,7 +296,7 @@ def Main():
   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.
@@ -283,7 +305,7 @@ def Main():
       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()
@@ -352,8 +374,13 @@ def Main():
 
         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()