view tests/test-status-inprocess.py.out @ 45320:4aa484efc926

templater: add exception-raising version of open_template()

I'm about to add another caller of `open_template()` (in the template
loader). That caller will want to get exceptions instead of `(None,
None)` if the template doesn't exist. This patch therefore changes
`open_template()` to raise exceptions and adds a new
`try_open_template()` that returns the `(None, None)` value.

Differential Revision: https://phab.mercurial-scm.org/D8905

% creating repo
% add and commit
C test.py
% change
M test.py