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 repo
$ cd repo
$ i=0; while [ "$i" -lt 213 ]; do echo a >> a; i=`expr $i + 1`; done
$ hg add a
$ cp a b
$ hg add b
Wide diffstat:
$ hg diff --stat
a | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
b | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 426 insertions(+), 0 deletions(-)
diffstat width:
$ COLUMNS=24 hg diff --config ui.interactive=true --stat
a | 213 ++++++++++++++
b | 213 ++++++++++++++
2 files changed, 426 insertions(+), 0 deletions(-)
$ hg ci -m adda
$ cat >> a <<EOF
> a
> a
> a
> EOF
Narrow diffstat:
$ hg diff --stat
a | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
$ hg ci -m appenda
>>> open("c", "wb").write("\0")
$ touch d
$ hg add c d
Binary diffstat:
$ hg diff --stat
c | Bin
1 files changed, 0 insertions(+), 0 deletions(-)
Binary git diffstat:
$ hg diff --stat --git
c | Bin
d | 0
2 files changed, 0 insertions(+), 0 deletions(-)
$ hg ci -m createb
>>> open("file with spaces", "wb").write("\0")
$ hg add "file with spaces"
Filename with spaces diffstat:
$ hg diff --stat
file with spaces | Bin
1 files changed, 0 insertions(+), 0 deletions(-)
Filename with spaces git diffstat:
$ hg diff --stat --git
file with spaces | Bin
1 files changed, 0 insertions(+), 0 deletions(-)
$ cd ..