tests/test-template-engine.t

stringutil: improve check for failed mailmap line parsing

The existing check for a bad mailmap file entry fails with inputs
like b'>@<'. This commit adds a function to check if a sufficient
amount of information has been parsed from a mailmap file entry.

At minimum, one email must be found (assumed to be the commit email).
If email is not empty and no names are found, then there must be
two emails. If there are at least one email and name, the mapping
is valid.

Differential Revision: https://phab.mercurial-scm.org/D3003

  $ cat > engine.py << EOF
  > 
  > from mercurial import (
  >     pycompat,
  >     templater,
  >     templateutil,
  > )
  > 
  > class mytemplater(templater.engine):
  >     def _load(self, t):
  >         return self._loader(t)
  > 
  >     def process(self, t, map):
  >         tmpl = self._load(t)
  >         props = self._defaults.copy()
  >         props.update(map)
  >         for k, v in props.items():
  >             if b'{{%s}}' % k not in tmpl:
  >                 continue
  >             if callable(v) and getattr(v, '_requires', None) is None:
  >                 props = self._resources.copy()
  >                 props.update(map)
  >                 v = v(**pycompat.strkwargs(props))
  >             elif callable(v):
  >                 v = v(self, props)
  >             v = templateutil.stringify(v)
  >             tmpl = tmpl.replace(b'{{%s}}' % k, v)
  >         yield tmpl
  > 
  > templater.engines[b'my'] = mytemplater
  > EOF
  $ hg init test
  $ echo '[extensions]' > test/.hg/hgrc
  $ echo "engine = `pwd`/engine.py" >> test/.hg/hgrc
  $ cd test
  $ cat > mymap << EOF
  > changeset = my:changeset.txt
  > EOF
  $ cat > changeset.txt << EOF
  > {{rev}} {{node}} {{author}}
  > EOF
  $ hg ci -Ama
  adding changeset.txt
  adding mymap
  $ hg log --style=./mymap
  0 97e5f848f0936960273bbf75be6388cd0350a32b test

  $ cat > changeset.txt << EOF
  > {{p1rev}} {{p1node}} {{p2rev}} {{p2node}}
  > EOF
  $ hg ci -Ama
  $ hg log --style=./mymap
  0 97e5f848f0936960273bbf75be6388cd0350a32b -1 0000000000000000000000000000000000000000
  -1 0000000000000000000000000000000000000000 -1 0000000000000000000000000000000000000000

invalid engine type:

  $ echo 'changeset = unknown:changeset.txt' > unknownenginemap
  $ hg log --style=./unknownenginemap
  abort: invalid template engine: unknown
  [255]

  $ cd ..