bpo-37409: fix relative import with no parent (#14956)

Relative imports use resolve_name to get the absolute target name,
which first seeks the current module's absolute package name from the globals:
If __package__ (and __spec__.parent) are missing then
import uses __name__, truncating the last segment if
the module is a submodule rather than a package __init__.py
(which it guesses from whether __path__ is defined).

The __name__ attempt should fail if there is no parent package (top level modules),
if __name__ is '__main__' (-m entry points), or both (scripts).
That is, if both __name__ has no subcomponents and the module does not seem
to be a package __init__ module then import should fail.

1 files changed, 1 insertions, 0 deletions

diff --git a/Misc/ACKS b/Misc/ACKS
index 6318998..d37d2bd 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -975,6 +975,7 @@ Alain Leufroy
 Mark Levinson
 Mark Levitt
 Ivan Levkivskyi
+Ben Lewis
 William Lewis
 Akira Li
 Robert Li