filemerge: explicitly tests for None
Changeset 758526333dec removed the mutable default value, but did not explicitly
tested for None. Such implicit testing can introduce semantic and performance
issue. We move to an explicit testing for None as recommended by PEP8:
https://www.python.org/dev/peps/pep-0008/#programming-recommendations
--- a/mercurial/filemerge.py Wed Mar 15 15:11:04 2017 -0700
+++ b/mercurial/filemerge.py Wed Mar 15 15:11:52 2017 -0700
@@ -36,7 +36,9 @@
return ui.configbool("merge-tools", tool + "." + part, default)
def _toollist(ui, tool, part, default=None):
- return ui.configlist("merge-tools", tool + "." + part, default or [])
+ if default is None:
+ default = []
+ return ui.configlist("merge-tools", tool + "." + part, default)
internals = {}
# Merge tools to document.