log: rewrite default template to use labels (
issue2866)
This is a complete rewrite of the default template to use labels. This
seems ultimately useless to me in most cases. The biggest benefit of
this patch to me seems to be a fairly complicated example of the
templating engine. It was a lot of hard work to figure out the precise
acceptable syntax, since it's almost undocumented. Hat tip to Steve
Losh's smartlog template, which helped me figure out a lot of the
syntax. Hopefully later I can use the present default log template
as an example for documenting the templating engine.
A test is attached. My goal was to match the --color=debug output,
which may differ slightly in newlines from the actual ANSI escape
codes output. I consider this an acceptable invisible deviation.
There seems to be a considerable slowdown with this rewrite.
Before:
$ time hg log -T default -r .~100::. > /dev/null
real 0m0.882s
user 0m0.812s
sys 0m0.064s
$ time hg log -T default -r .~100::. > /dev/null
real 0m0.872s
user 0m0.796s
sys 0m0.068s
$ time hg log -T default -r .~100::. > /dev/null
real 0m0.917s
user 0m0.836s
sys 0m0.076s
After:
$ time hg log -T default -r .~100::. > /dev/null
real 0m1.480s
user 0m1.392s
sys 0m0.072s
$ time hg log -T default -r .~100::. > /dev/null
real 0m1.500s
user 0m1.400s
sys 0m0.088s
$ time hg log -T default -r .~100::. > /dev/null
real 0m1.462s
user 0m1.364s
sys 0m0.092s
Following the maxim, "make it work, profile, make it faster, in that
order", I deem this slowdown acceptable for now.
I suspect but have not confirmed that a big slowdown comes from
calling keywords twice in the file templates, once to test the
existence of output and again to actually list the output. If so, a
simple speedup might be to improve the templating engine to cache
keywords when called more than once on the same revision.
TODO: I found a bug while working on this. The following stack traces:
hg log -r . -T '{ifcontains(phase, "secret public", "lol", "omg")}\n'
log: do not hide the public phase in debug mode (BC)
When
51fc43253a52 introduced phases to the `hg log --debug` output, it
also disabled outputting public phase. At the same time, it always
shows phases in the default template, `hg log --debug -T default`.
Those two should produce the same output, but they don't.
I think it makes a lot more sense to always show all phases. There's
already loss of backwards compatibility in this case when using a
newer hg on an old hg repo, since draft commits will show up in the
output of `hg log --debug`.
Finally, I just don't think that any sort of information should be
hidden with --debug. This flag should be about showing as much
information as possible.
templater: set the correct phase for parents
Akin to
f6371cc62d2a which did this for `hg log`, the following sets
the correct phase for the {phase} keyword when the context is a parent
of the current cset. This allows templates such as the following to be
defined,
parent = '{label("log.parent changeset.{phase}",
"parent: {rev}:{node|formatnode}")}\n'
which when called on a parent (e.g. with the `parents` template
keyword), will produce the correct phase.
color: omit debug label output on empty strings
This is most noticeable when using custom templates. Before this
patch, a template like {label("foo.bar", baz)} would emit
[foo.bar|]
whenever baz was empty. This cset simply omits all output when baz is
empty.
revset: use _generatorset in _revancestors
The _descgeneratorset class is going away.