Merge pull request #5047 from minrk/check-pkg-data

only validate package_data when it might be used

setup.py

@@ -58,6 +58,7 b' from setupbase import ('
     setup_args,
     find_packages,
     find_package_data,
+    check_package_data_first,
     find_entry_points,
     build_scripts_entrypt,
     find_data_files,
@@ -191,6 +192,7 b" if len(sys.argv) >= 2 and sys.argv[1] in ('sdist','bdist_rpm'):"
 
 packages = find_packages()
 package_data = find_package_data()
+
 data_files = find_data_files()
 
 setup_args['packages'] = packages
@@ -224,7 +226,7 b' class UploadWindowsInstallers(upload):'
             self.upload_file('bdist_wininst', 'any', dist_file)
 
 setup_args['cmdclass'] = {
-    'build_py': git_prebuild('IPython'),
+    'build_py': check_package_data_first(git_prebuild('IPython')),
     'sdist' : git_prebuild('IPython', sdist),
     'upload_wininst' : UploadWindowsInstallers,
     'submodule' : UpdateSubmodules,

setupbase.py

@@ -188,7 +188,12 b' def find_package_data():'
         'IPython.nbformat' : ['tests/*.ipynb']
     }
     
-    # verify that package_data makes sense
+    return package_data
+
+
+def check_package_data(package_data):
+    """verify that package_data globs make sense"""
+    print("checking package data")
     for pkg, data in package_data.items():
         pkg_root = pjoin(*pkg.split('.'))
         for d in data:
@@ -198,7 +203,17 b' def find_package_data():'
             else:
                 assert os.path.exists(path), "Missing package data: %s" % path
 
-    return package_data
+
+def check_package_data_first(command):
+    """decorator for checking package_data before running a given command
+    
+    Probably only needs to wrap build_py
+    """
+    class DecoratedCommand(command):
+        def run(self):
+            check_package_data(self.package_data)
+            command.run(self)
+    return DecoratedCommand
 
 
 #---------------------------------------------------------------------------