diff mercurial/formatter.py @ 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

--- a/mercurial/formatter.py	Wed Aug 05 22:13:51 2020 -0700
+++ b/mercurial/formatter.py	Thu Aug 06 09:50:10 2020 -0700
@@ -600,9 +600,9 @@
 
     # perhaps a stock style?
     if not os.path.split(tmpl)[0]:
-        (mapname, fp) = templater.open_template(
+        (mapname, fp) = templater.try_open_template(
             b'map-cmdline.' + tmpl
-        ) or templater.open_template(tmpl)
+        ) or templater.try_open_template(tmpl)
         if mapname:
             return mapfile_templatespec(topic, mapname, fp)