Reverting removal of prepare_command to maintain backwards compatibility of configurations with {python} and {pip}

cibuildwheel/linux.py

@@ -1,6 +1,7 @@
 from __future__ import print_function
 import os, subprocess, sys
 from collections import namedtuple
+from .util import prepare_command
 
 try:
     from shlex import quote as shlex_quote
@@ -104,7 +105,9 @@ def build(project_dir, package_name, output_dir, test_command, test_requires, be
             test_command=shlex_quote(
                 test_command.format(project='/project') if test_command else ''
             ),
-            before_build=shlex_quote(before_build or ''),
+            before_build=shlex_quote(
+                prepare_command(before_build, python='python', pip='pip') if before_build else ''
+            ),
             environment_exports='\n'.join(environment.as_shell_commands()),
         )
 

cibuildwheel/macos.py

@@ -7,6 +7,8 @@ try:
 except ImportError:
     from pipes import quote as shlex_quote
 
+from .util import prepare_command
+
 
 def build(project_dir, package_name, output_dir, test_command, test_requires, before_build, skip, environment):
     PythonConfiguration = namedtuple('PythonConfiguration', ['version', 'identifier', 'url'])
@@ -83,7 +85,8 @@ def build(project_dir, package_name, output_dir, test_command, test_requires, be
 
         # run the before_build command
         if before_build:
-            call(before_build, env=env, shell=True)
+            before_build_prepared = prepare_command(before_build, python='python', pip='pip')
+            call(before_build_prepared, env=env, shell=True)
 
         # build the wheel
         call(['pip', 'wheel', abs_project_dir, '-w', '/tmp/built_wheel', '--no-deps'], env=env)

cibuildwheel/util.py

@@ -1,6 +1,18 @@
 from fnmatch import fnmatch
 
 
+def prepare_command(command, python, pip):
+    '''
+    Preprocesses a command by expanding variables like {python} or {pip}.
+
+    For example, used for the before_build option, where the user would
+    like to run a command like `python setup.py test`. If the command should run on
+    Python 3, the user could write `{python} setup.py test`. This command would expand
+    it out to python2 or python3 as appropriate.
+    '''
+    return command.format(python=python, pip=pip)
+
+
 class BuildSkipper(object):
     def __init__(self, skip_config):
         self.patterns = skip_config.split()

cibuildwheel/windows.py

@@ -7,7 +7,7 @@ except ImportError:
 from collections import namedtuple
 from glob import glob
 
-from .util import Unbuffered
+from .util import prepare_command, Unbuffered
 
 
 def build(project_dir, package_name, output_dir, test_command, test_requires, before_build, skip, environment):
@@ -78,7 +78,8 @@ def build(project_dir, package_name, output_dir, test_command, test_requires, be
 
         # run the before_build command
         if before_build:
-            shell([before_build], env=env)
+            before_build_prepared = prepare_command(before_build, python='python', pip='pip')
+            shell([before_build_prepared], env=env)
 
         # build the wheel
         shell(['pip', 'wheel', abs_project_dir, '-w', built_wheel_dir, '--no-deps'], env=env)