Detect and warn on missing vcvarsall.bat

build/toolchain/win/setup_toolchain.py

Index: build/toolchain/win/setup_toolchain.py
diff --git a/build/toolchain/win/setup_toolchain.py b/build/toolchain/win/setup_toolchain.py
index 4dd077cc1c1b4a8ed004d8256bcde85cbdc22b5b..f91239a43ffc5c3ca6c1ed416730f4f90de3bd41 100644
--- a/build/toolchain/win/setup_toolchain.py
+++ b/build/toolchain/win/setup_toolchain.py
@@ -117,9 +117,13 @@ def _LoadToolchainEnv(cpu, sdk_dir):
     if 'GYP_MSVS_OVERRIDE_PATH' not in os.environ:
       os.environ['GYP_MSVS_OVERRIDE_PATH'] = _DetectVisualStudioPath()
     # We only support x64-hosted tools.
-    args = [os.path.normpath(os.path.join(os.environ['GYP_MSVS_OVERRIDE_PATH'],
-                                          'VC/vcvarsall.bat')),
-            'amd64_x86' if cpu == 'x86' else 'amd64']
+    script_path = os.path.normpath(os.path.join(
+                                   os.environ['GYP_MSVS_OVERRIDE_PATH'],

[scottmg, 2016/03/23 19:41:53]

Yeah, I wish we had a good python formatter that wasn't terribly slow and didn't
reformat the whole file. :(

I just meant that this alignment makes it look like you're passing 3 arguments
to normpath(). I would indent os.environ[...] and 'VC/...' 4 spaces to make it
clear they're subordinate to join(), and there's only one argument being passed
to normpath().

[brucedawson, 2016/03/23 19:48:51]

Done.

+                                   'VC/vcvarsall.bat'))
+    if not os.path.exists(script_path):
+      raise Exception('%s is missing - make sure VC++ tools are installed.'
+                       % script_path)

[scottmg, 2016/03/23 19:41:53]

Sorry, I should have been clearer. The binary operator goes on the preceding
line, not the same line as the RHS of the binary operator, so:

raise Exception('%s is missing - make sure VC++ tools are installed.' %
    script_path)

but you had script_path aligned properly before, it should be under the '
following Exception(.

[brucedawson, 2016/03/23 19:48:51]

Done.

+    args = [script_path, 'amd64_x86' if cpu == 'x86' else 'amd64']
     variables = _LoadEnvFromBat(args)
   return _ExtractImportantEnvironment(variables)