# HG changeset patch
# User Gregory Szorc <gps@mozilla.com>
# Date 1522778400 25200
#      Tue Apr 03 11:00:00 2018 -0700
# Node ID af5755fcc4882a24fa25402a7035796dc9a6258c
# Parent  d92f42325e50fd831bd905f3f3a8dce1d706bfcd
Bug 1451065 - Require Python 3.5+ to build; r=mshal

But only if we are:

a) not running in CI
b) running in CI on Linux

We will ideally make the requirement global. But Python 3.5 is not
yet available in CI on macOS. And we're not finding the MozillaBuild
copy in configure.

This was previously announced in November at
https://groups.google.com/d/msg/mozilla.dev.platform/rJrPh1QYXrQ/hqRrQsJ_BgAJ.

MozReview-Commit-ID: IyPCAcL3gop

diff --git a/build/moz.configure/init.configure b/build/moz.configure/init.configure
--- a/build/moz.configure/init.configure
+++ b/build/moz.configure/init.configure
@@ -374,23 +374,24 @@ shell = help_shell | shell
 
 
 # Python 3
 # ========
 
 option(env='PYTHON3', nargs=1, help='Python 3 interpreter (3.5 or later)')
 
 
-@depends('PYTHON3')
+@depends('PYTHON3', 'MOZ_AUTOMATION')
 @checking('for Python 3',
           callback=lambda x: '%s (%s)' % (x.path, x.str_version) if x else 'no')
 @imports(_from='__builtin__', _import='Exception')
+@imports('platform')
 @imports(_from='mozbuild.pythonutil', _import='find_python3_executable')
 @imports(_from='mozbuild.pythonutil', _import='python_executable_version')
-def python3(env_python):
+def python3(env_python, automation):
     python = env_python[0] if env_python else None
 
     # If Python given by environment variable, it must work.
     if python:
         try:
             version = python_executable_version(python).version
         except Exception as e:
             raise FatalCheckError('could not determine version of PYTHON '
@@ -398,21 +399,32 @@ def python3(env_python):
 
         if version < (3, 5, 0):
             raise FatalCheckError('PYTHON3 must point to Python 3.5 or newer; '
                                   '%d.%d found' % (version[0], version[1]))
     else:
         # Fall back to the search routine.
         python, version = find_python3_executable(min_version='3.5.0')
 
-        if not python:
+        # The API returns a bytes whereas everything in configure is unicode.
+        if python:
+            python = python.decode('utf-8')
+
+    # Outside of automation, require Python 3.5.
+    # In automation, only require where it is known to be installed.
+    require = not automation or platform.system() == 'Linux'
+
+    if not python:
+        if not require:
             return None
 
-        # The API returns a bytes whereas everything in configure is unicode.
-        python = python.decode('utf-8')
+        raise FatalCheckError('Python 3.5 or newer is required to build. '
+                              'Ensure a `python3.x` executable is in your '
+                              'PATH or define PYTHON3 to point to a Python '
+                              '3.5 executable.')
 
     return namespace(
         path=python,
         version=version,
         str_version='.'.join(str(v) for v in version),
     )