annotate mercurial/templates/map-cmdline.default @ 22766:0ded0f0b1c04

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'

# Base templates. Due to name clashes with existing keywords, we have
# to replace some keywords with 'lkeyword', for 'labelled keyword'
changeset = '{cset}{branches}{bookmarks}{tags}{parents}{user}{ldate}{summary}\n'
changeset_quiet = '{node}'
changeset_verbose = '{cset}{branches}{bookmarks}{tags}{parents}{user}{ldate}{lfiles}{lfile_copies_switch}{description}\n'
changeset_debug = '{fullcset}{branches}{bookmarks}{tags}{lphase}{parents}{manifest}{user}{ldate}{lfile_mods}{lfile_adds}{lfile_dels}{lfile_copies_switch}{extras}{description}\n'

# File templates
lfiles = '{if(files,
               label("ui.note log.files",
                     "files:       {files}\n"))}'

lfile_mods = '{if(file_mods,
                  label("ui.debug log.files",
                        "files:       {file_mods}\n"))}'

lfile_adds = '{if(file_adds,
                  label("ui.debug log.files",
                        "files+:      {file_adds}\n"))}'

lfile_dels = '{if(file_dels,
                  label("ui.debug log.files",
                        "files-:      {file_dels}\n"))}'

lfile_copies_switch = '{if(file_copies_switch,
                           label("ui.note log.copies",
                                 "copies:     {file_copies_switch
                                               % ' {name} ({source})'}\n"))}'

# General templates
cset = '{label("log.changeset changeset.{phase}",
               "changeset:   {rev}:{node|short}")}\n'

lphase = '{label("log.phase",
                 "phase:       {phase}")}\n'

fullcset = '{label("log.changeset changeset.{phase}",
                   "changeset:   {rev}:{node}")}\n'

parent = '{label("log.parent changeset.{phase}",
                  "parent:      {rev}:{node|formatnode}")}\n'

node = '{label("log.node",
                "{rev}:{node|short}")}\n'

manifest = '{label("ui.debug log.manifest",
                   "manifest:    {rev}:{node}")}\n'

branch = '{label("log.branch",
                 "branch:      {branch}")}\n'

tag = '{label("log.tag",
              "tag:         {tag}")}\n'

bookmark = '{label("log.bookmark",
                   "bookmark:    {bookmark}")}\n'

user = '{label("log.user",
               "user:        {author}")}\n'

summary = '{label("log.summary",
                  "summary:     {desc|firstline}")}\n'

ldate = '{label("log.date",
                "date:        {date|date}")}\n'

extra = '{label("ui.debug log.extra",
                "extra:       {key}={value|stringescape}")}\n'

description = '{label("ui.note log.description",
                       "description:")}
               {label("ui.note log.description",
                       "{desc|strip}")}\n\n'