Add Python version test to detect {} in version strings.

- {} is not compatible with Python 2.6

lib/spack/external/pyqver2.py

@@ -165,12 +165,24 @@ def visitCallFunc(self, node):
         def rollup(n):
             if isinstance(n, compiler.ast.Name):
                 return n.name
+            elif isinstance(n, compiler.ast.Const):
+                return type(n.value).__name__
             elif isinstance(n, compiler.ast.Getattr):
                 r = rollup(n.expr)
                 if r:
                     return r + "." + n.attrname
         name = rollup(node.node)
         if name:
+            # Special handling for empty format strings, which aren't
+            # allowed in Python 2.6
+            if name in ('unicode.format', 'str.format'):
+                n = node.node
+                if isinstance(n, compiler.ast.Getattr):
+                    n = n.expr
+                    if isinstance(n, compiler.ast.Const):
+                        if '{}' in n.value:
+                            self.add(node, (2,7), name + ' with {} format string')
+
             v = Functions.get(name)
             if v is not None:
                 self.add(node, v, name)

lib/spack/spack/test/python_version.py

@@ -41,13 +41,10 @@
 
 class PythonVersionTest(unittest.TestCase):
 
-    def spack_python_files(self):
+    def pyfiles(self, *search_paths):
         # first file is the spack script.
         yield spack.spack_file
 
-        # Next files are all the source files and package files.
-        search_paths = [spack.lib_path, spack.var_path]
-
         # Iterate through the whole spack source tree.
         for path in search_paths:
             for root, dirnames, filenames in os.walk(path):
@@ -56,16 +53,20 @@ def spack_python_files(self):
                         yield os.path.join(root, filename)
 
 
-    def all_package_py_files(self):
+    def package_py_files(self):
         for name in spack.db.all_package_names():
             yield spack.db.filename_for_package_name(name)
 
 
-    def check_python_versions(self, files):
+    def check_python_versions(self, *files):
         # dict version -> filename -> reasons
         all_issues = {}
 
         for fn in files:
+            if fn != '/Users/gamblin2/src/spack/var/spack/packages/vim/package.py':
+                continue
+            print fn
+
             with open(fn) as pyfile:
                 versions = pyqver2.get_versions(pyfile.read())
                 for ver, reasons in versions.items():
@@ -101,8 +102,8 @@ def check_python_versions(self, files):
 
 
     def test_core_module_compatibility(self):
-        self.check_python_versions(self.spack_python_files())
+        self.check_python_versions(*self.pyfiles(spack.lib_path))
 
 
     def test_package_module_compatibility(self):
-        self.check_python_versions(self.all_package_py_files())
+        self.check_python_versions(*self.pyfiles(spack.packages_path))