demandimport: error out early on missing attribute of non package (
issue5373)
If the parent module isn't a package, all valid attributes must be obtained
from it. We can raise ImportError early if any attributes not found.
--- a/mercurial/demandimport.py Tue Sep 27 21:56:00 2016 +0900
+++ b/mercurial/demandimport.py Mon Sep 26 23:28:57 2016 +0900
@@ -191,11 +191,16 @@
def processfromitem(mod, attr):
"""Process an imported symbol in the import statement.
- If the symbol doesn't exist in the parent module, it must be a
- module. We set missing modules up as _demandmod instances.
+ If the symbol doesn't exist in the parent module, and if the
+ parent module is a package, it must be a module. We set missing
+ modules up as _demandmod instances.
"""
symbol = getattr(mod, attr, nothing)
+ nonpkg = getattr(mod, '__path__', nothing) is nothing
if symbol is nothing:
+ if nonpkg:
+ # do not try relative import, which would raise ValueError
+ raise ImportError('cannot import name %s' % attr)
mn = '%s.%s' % (mod.__name__, attr)
if mn in ignore:
importfunc = _origimport
--- a/tests/test-demandimport.py Tue Sep 27 21:56:00 2016 +0900
+++ b/tests/test-demandimport.py Mon Sep 26 23:28:57 2016 +0900
@@ -63,6 +63,15 @@
print("re.stderr =", f(re.stderr))
print("re =", f(re))
+import contextlib
+print("contextlib =", f(contextlib))
+try:
+ from contextlib import unknownattr
+ print('no demandmod should be created for attribute of non-package '
+ 'module:\ncontextlib.unknownattr =', f(unknownattr))
+except ImportError as inst:
+ print('contextlib.unknownattr = ImportError: %s' % inst)
+
demandimport.disable()
os.environ['HGDEMANDIMPORT'] = 'disable'
# this enable call should not actually enable demandimport!
--- a/tests/test-demandimport.py.out Tue Sep 27 21:56:00 2016 +0900
+++ b/tests/test-demandimport.py.out Mon Sep 26 23:28:57 2016 +0900
@@ -16,4 +16,6 @@
re = <unloaded module 'sys'>
re.stderr = <open file '<whatever>', mode 'w' at 0x?>
re = <proxied module 'sys'>
+contextlib = <unloaded module 'contextlib'>
+contextlib.unknownattr = ImportError: cannot import name unknownattr
node = <module 'mercurial.node' from '?'>