Output better error messages during build

The python build scripts use subprocess.check_call() for external
commands (aapt, javac, etc). On a failure, it prints the python
stacktrace, followed by the command being run (in a form that can be
copy-pasted and actually work), followed by the output from the command.

Previously, it was printing command output, then command, then
stacktrace which is much less useful.


Review URL: https://chromiumcodereview.appspot.com/12913028

git-svn-id: http://src.chromium.org/svn/trunk/src/build@191300 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/dex.py

@@ -7,7 +7,6 @@
 import fnmatch
 import optparse
 import os
-import subprocess
 import sys
 
 from pylib import build_utils
@@ -16,7 +15,7 @@ from pylib import build_utils
 def DoDex(options, paths):
   dx_binary = os.path.join(options.android_sdk_root, 'platform-tools', 'dx')
   dex_cmd = [dx_binary, '--dex', '--output', options.dex_path] + paths
-  subprocess.check_call(dex_cmd)
+  build_utils.CheckCallDie(dex_cmd)
 
 
 def main(argv):

android/jar.py

@@ -7,7 +7,6 @@
 import fnmatch
 import optparse
 import os
-import subprocess
 import sys
 
 from pylib import build_utils
@@ -27,7 +26,7 @@ def DoJar(options):
   jar_cwd = options.classes_dir
   class_files = [os.path.relpath(f, jar_cwd) for f in class_files]
   jar_cmd = ['jar', 'cf0', jar_path] + class_files
-  subprocess.check_call(jar_cmd, cwd=jar_cwd)
+  build_utils.CheckCallDie(jar_cmd, cwd=jar_cwd)
 
 
 def main(argv):

android/javac.py

@@ -7,7 +7,6 @@
 import fnmatch
 import optparse
 import os
-import subprocess
 import sys
 
 from pylib import build_utils
@@ -41,7 +40,7 @@ def DoJavac(options):
   build_utils.DeleteDirectory(output_dir)
   build_utils.MakeDirectory(output_dir)
 
-  subprocess.check_call([
+  build_utils.CheckCallDie([
       'javac',
       '-g',
       '-Xlint:unchecked',

android/process_resources.py

@@ -9,7 +9,6 @@
 import optparse
 import os
 import shlex
-import subprocess
 
 from pylib import build_utils
 
@@ -80,17 +79,20 @@ def main():
     package_command.append('--non-constant-id')
   if options.custom_package:
     package_command += ['--custom-package', options.custom_package]
-  subprocess.check_call(package_command)
+  build_utils.CheckCallDie(package_command)
 
   # Crunch image resources. This shrinks png files and is necessary for 9-patch
   # images to display correctly.
   build_utils.MakeDirectory(options.crunch_output_dir)
-  subprocess.check_call([aapt,
-                         'crunch',
-                         '-S', options.crunch_input_dir,
-                         '-C', options.crunch_output_dir])
 
-  build_utils.Touch(options.stamp)
+  aapt_cmd = [aapt,
+              'crunch',
+              '-S', options.crunch_input_dir,
+              '-C', options.crunch_output_dir]
+  build_utils.CheckCallDie(aapt_cmd)
+
+  if options.stamp:
+    build_utils.Touch(options.stamp)
 
 
 if __name__ == '__main__':

android/pylib/build_utils.py

@@ -4,8 +4,12 @@
 
 import fnmatch
 import os
+import pipes
 import shlex
 import shutil
+import subprocess
+import sys
+import traceback
 
 
 def MakeDirectory(dir_path):
@@ -51,3 +55,36 @@ def ParseGypList(gyp_string):
   return shlex.split(gyp_string)
 
 
+# This can be used in most cases like subprocess.check_call. The output,
+# particularly when the command fails, better highlights the command's failure.
+# This call will directly exit on a failure in the subprocess so that no python
+# stacktrace is printed after the output of the failed command.
+def CheckCallDie(args, cwd=None):
+  if not cwd:
+    cwd = os.getcwd()
+
+  child = subprocess.Popen(args,
+      stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=cwd)
+
+  stdout, _ = child.communicate()
+
+  if child.returncode:
+    stacktrace = traceback.extract_stack()
+    print >> sys.stderr, ''.join(traceback.format_list(stacktrace))
+    # A user should be able to simply copy and paste the command that failed
+    # into their shell.
+    copyable_command = ' '.join(map(pipes.quote, args))
+    copyable_command = ('( cd ' + os.path.abspath(cwd) + '; '
+        + copyable_command + ' )')
+    print >> sys.stderr, 'Command failed:', copyable_command, '\n'
+
+    if stdout:
+      print stdout,
+
+    # Directly exit to avoid printing stacktrace.
+    sys.exit(child.returncode)
+
+  else:
+    if stdout:
+      print stdout,
+

android/strip_library_for_apk.py

@@ -6,7 +6,6 @@
 
 import optparse
 import os
-import subprocess
 import sys
 
 from pylib import build_utils
@@ -16,7 +15,7 @@ def StripLibrary(android_strip, android_strip_args, library_path, output_path):
   strip_cmd = ([android_strip] +
                android_strip_args +
                ['-o', output_path, library_path])
-  subprocess.check_call(strip_cmd)
+  build_utils.CheckCallDie(strip_cmd)
 
 
 def main(argv):