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'
$ hg init
$ echo 0 > a
$ echo 0 > b
$ hg ci -A -m m
adding a
adding b
$ hg rm a
$ hg cat a
0
$ hg cat --decode a # more tests in test-encode
0
$ echo 1 > b
$ hg ci -m m
$ echo 2 > b
$ hg cat -r 0 a
0
$ hg cat -r 0 b
0
$ hg cat -r 1 a
a: no such file in rev 7040230c159c
[1]
$ hg cat -r 1 b
1
Test fileset
$ echo 3 > c
$ hg ci -Am addmore c
$ hg cat 'set:not(b) or a'
3
$ hg cat 'set:c or b'
1
3
$ mkdir tmp
$ hg cat --output tmp/HH_%H c
$ hg cat --output tmp/RR_%R c
$ hg cat --output tmp/h_%h c
$ hg cat --output tmp/r_%r c
$ hg cat --output tmp/%s_s c
$ hg cat --output tmp/%d%%_d c
$ hg cat --output tmp/%p_p c
$ hg log -r . --template "{rev}: {node|short}\n"
2: 45116003780e
$ find tmp -type f | sort
tmp/.%_d
tmp/HH_45116003780e3678b333fb2c99fa7d559c8457e9
tmp/RR_2
tmp/c_p
tmp/c_s
tmp/h_45116003780e
tmp/r_2