[GN] Use "xcrun" instead of "xcodebuild" to get information on SDK.

build/config/mac/sdk_info.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import os
 import subprocess
 import sys
 
 # This script prints information about the build system, the operating
 # system and the iOS or Mac SDK (depending on the platform "iphonesimulator",
 # "iphoneos" or "macosx" generally).
 #
 # In the GYP build, this is done inside GYP itself based on the SDKROOT
 # variable.
 
 def FormatVersion(version):
   """Converts Xcode version to a format required for Info.plist."""
   version = version.replace('.', '')
   version = version + '0' * (3 - len(version))
   return version.zfill(4)
 
 
 def FillXcodeVersion(settings):
   """Fills the Xcode version and build number into |settings|."""
   lines = subprocess.check_output(['xcodebuild', '-version']).splitlines()

[sdefresne, 2016/05/18 09:42:39]

I have not found an "xcrun" substitute for those so I've kept this invocation of
"xcodebuild". It appears to be much faster than the other, so let's see if this
does better.

   settings['xcode_version'] = FormatVersion(lines[0].split()[-1])
   settings['xcode_build'] = lines[-1].split()[-1]
 
 
 def FillMachineOSBuild(settings):
   """Fills OS build number into |settings|."""
   settings['machine_os_build'] = subprocess.check_output(
       ['sw_vers', '-buildVersion']).strip()
 
 
 def FillSDKPathAndVersion(settings, platform):
   """Fills the SDK path and version for |platform| into |settings|."""
-  lines = subprocess.check_output(['xcodebuild', '-version', '-sdk',
-      platform, 'Path', 'SDKVersion', 'ProductBuildVersion']).splitlines()
-  settings['sdk_path'] = lines[0]
-  settings['sdk_version'] = lines[1]
-  settings['sdk_build'] = lines[2]
+  settings['sdk_path'] = subprocess.check_output([
+      'xcrun', '-sdk', platform, '--show-sdk-path']).strip()
+  settings['sdk_version'] = subprocess.check_output([
+      'xcrun', '-sdk', platform, '--show-sdk-version']).strip()
+  settings['sdk_build'] = subprocess.check_output([
+      'xcrun', '-sdk', platform, '--show-sdk-build-version']).strip()

[Nico, 2016/05/18 11:21:06]

Hm, my xcrun doesn't know --show-sdk-build-version yet. I'm on Xcode 7.0. Some
of the bots are on 5.0 still I think.

Since this computes xcode_version above, maybe this could check if the
xcode_version is new enough and if so call xcrun and else call xcodebuild to get
it?

Why is this field needed at all? gyp never queries for ProductBuildVersion as
far as I can tell.

It does query --show-sdk-build-version, but only:

      if xcode >= '0720':
        cache['DTSDKBuild'] = self._GetSdkVersionInfoItem(
            sdk_root, '--show-sdk-build-version')
      elif xcode >= '0430':
        cache['DTSDKBuild'] = sdk_version
      else:
        cache['DTSDKBuild'] = cache['BuildMachineOSBuild']

(where sdk_version is the result from --show-sdk-version)

Can we do the same here (we can assume 4.3), with a TODO to unconditionally use
--show-sdk-build-version once all bots are on Xcode 7.2?

[sdefresne, 2016/05/18 14:45:02]

I don't know why gyp does not use it, but when I build downstream, the value
that ends up in my Info.plist is the value returned by "xcrun -sdk iphoneos
--show-sdk-build-version". I also get the same value when I build with
xcodebuild so it is possible that it comes from one environment variable set by
Xcode when it invokes ninja in hybrid build mode.

I can remove it but then I have a diff when I compare the output of
gyp/xcodebuild and gn builds.

 
 
 if __name__ == '__main__':
   if len(sys.argv) != 2:
     sys.stderr.write(
         'usage: %s [iphoneos|iphonesimulator|macosx]\n' %
         os.path.basename(sys.argv[0]))
     sys.exit(1)
 
   settings = {}
   FillSDKPathAndVersion(settings, sys.argv[1])
   FillMachineOSBuild(settings)
   FillXcodeVersion(settings)
 
   for key in sorted(settings):
     print '%s="%s"' % (key, settings[key])