Updated python: refactoring and warning messages.

var/spack/repos/builtin/packages/python/package.py

@@ -29,10 +29,11 @@
 
 import spack
 import llnl.util.tty as tty
-import yaml
 from llnl.util.lang import match_predicate
+from llnl.util.filesystem import force_remove
 from spack import *
 from spack.util.environment import *
+import spack.util.spack_json as sjson
 
 
 class Python(Package):
@@ -78,6 +79,10 @@ class Python(Package):
 
     patch('ncurses.patch')
 
+    _DISTUTIL_VARS_TO_SAVE = ['LDSHARED']
+    _DISTUTIL_CACHE_FILENAME = 'sysconfig.json'
+    _distutil_vars = None
+
     @when('@2.7,3.4:')
     def patch(self):
         # NOTE: Python's default installation procedure makes it possible for a
@@ -134,7 +139,7 @@ def install(self, spec, prefix):
         make()
         make('install')
 
-        self.save_distutils_data(prefix)
+        self._save_distutil_vars(prefix)
 
         self.filter_compilers(prefix)
 
@@ -176,7 +181,7 @@ def install(self, spec, prefix):
     #            >>> import Tkinter
     #            >>> Tkinter._test()
 
-    def save_distutils_data(self, prefix):
+    def _save_distutil_vars(self, prefix):
         """
         Run before changing automatically generated contents of the
         _sysconfigdata.py, which is used by distutils to figure out what
@@ -188,6 +193,8 @@ def save_distutils_data(self, prefix):
         autogenerated value to pass it to the dependant package's setup script.
         """
 
+        self._distutil_vars = {}
+
         input_filename = None
         for filename in [join_path(lib_dir,
                                    'python{0}'.format(self.version.up_to(2)),
@@ -201,7 +208,6 @@ def save_distutils_data(self, prefix):
             return
 
         input_dict = None
-
         try:
             with open(input_filename) as input_file:
                 match = re.search(r'build_time_vars\s*=\s*(?P<dict>{.*})',
@@ -214,45 +220,60 @@ def save_distutils_data(self, prefix):
             pass
 
         if not input_dict:
+            tty.warn('Failed to find \'build_time_vars\' dictionary in file '
+                     '\'%s\'. This might cause the extensions that are '
+                     'installed with distutils to call compilers directly '
+                     'avoiding Spack\'s wrappers.' % input_filename)
             return
 
-        vars_to_save = ['LDSHARED']
-        saved_vars = {}
-
-        for var_name in vars_to_save:
+        for var_name in Python._DISTUTIL_VARS_TO_SAVE:
             if var_name in input_dict:
-                saved_vars[var_name] = input_dict[var_name]
-
-        if len(saved_vars) > 0:
+                self._distutil_vars[var_name] = input_dict[var_name]
+            else:
+                tty.warn('Failed to find key \'%s\' in \'build_time_vars\' '
+                         'dictionary in file \'%s\'. This might cause the '
+                         'extensions that are installed with distutils to '
+                         'call compilers directly avoiding Spack\'s wrappers.'
+                         % (var_name, input_filename))
+
+        if len(self._distutil_vars) > 0:
+            output_filename = None
             try:
                 output_filename = join_path(
                     spack.store.layout.metadata_path(self.spec),
-                    'sysconfig.yaml')
+                    Python._DISTUTIL_CACHE_FILENAME)
                 with open(output_filename, 'w') as output_file:
-                    yaml.dump(saved_vars, stream=output_file,
-                              default_flow_style=False)
-            except (yaml.YAMLError, IOError):
+                    sjson.dump(self._distutil_vars, output_file)
+            except:
+                tty.warn('Failed to save metadata for distutils. This might '
+                         'cause the extensions that are installed with '
+                         'distutils to call compilers directly avoiding '
+                         'Spack\'s wrappers.')
+                # We make the cache empty if we failed to save it to file
+                # to provide the same behaviour as in the case when the cache
+                # is initialized by the method load_distutils_data().
+                self._distutil_vars = {}
+                if output_filename:
+                    force_remove(output_filename)
+
+    def _load_distutil_vars(self):
+        # We update and keep the cache unchanged only if the package is
+        # installed.
+        if not self._distutil_vars and self.installed:
+            try:
+                input_filename = join_path(
+                    spack.store.layout.metadata_path(self.spec),
+                    Python._DISTUTIL_CACHE_FILENAME)
+                if os.path.isfile(input_filename):
+                    with open(input_filename) as input_file:
+                        self._distutil_vars = sjson.load(input_file)
+            except:
                 pass
 
-        setattr(self, '_distutils_data_cache', saved_vars)
-
-    def load_distutils_data(self):
-        if not hasattr(self, '_distutils_data_cache'):
-            input_filename = join_path(
-                spack.store.layout.metadata_path(self.spec),
-                'sysconfig.yaml')
-            if os.path.isfile(input_filename):
-                try:
-                    with open(input_filename) as input_file:
-                        setattr(self, '_distutils_data_cache',
-                                yaml.load(input_file))
-                except (yaml.YAMLError, IOError):
-                    pass
-                
-            if not hasattr(self, '_distutils_data_cache'):
-                setattr(self, '_distutils_data_cache', None)
+            if not self._distutil_vars:
+                self._distutil_vars = {}
 
-        return self._distutils_data_cache
+        return self._distutil_vars
 
     def filter_compilers(self, prefix):
         """Run after install to tell the configuration files and Makefiles
@@ -350,10 +371,10 @@ def setup_dependent_package(self, module, ext_spec):
         module.python = Executable(python_path)
         module.setup_py = Executable(python_path + ' setup.py --no-user-cfg')
 
-        distutils_data = self.load_distutils_data()
+        distutil_vars = self._load_distutil_vars()
 
-        if distutils_data:
-            for key, value in distutils_data.iteritems():
+        if distutil_vars:
+            for key, value in distutil_vars.iteritems():
                 module.setup_py.add_default_env(key, value)
 
         # Add variables for lib/pythonX.Y and lib/pythonX.Y/site-packages dirs.