completion: add a debugpathcomplete command
The bash_completion code uses "hg status" to generate a list of
possible completions for commands that operate on files in the
working directory. In a large working directory, this can result
in a single tab-completion being very slow (several seconds) as a
result of checking the status of every file, even when there is no
need to check status or no possible matches.
The new debugpathcomplete command gains performance in a few simple
ways:
* Allow completion to operate on just a single directory. When used
to complete the right commands, this considerably reduces the
number of completions returned, at no loss in functionality.
* Never check the status of files. For completions that really must
know if a file is modified, it is faster to use status:
hg status -nm 'glob:myprefix**'
Performance:
Here are the commands used by bash_completion to complete, run in
the root of the mozilla-central working dir (~77,000 files) and
another repo (~165,000 files):
All "normal state" files (used by e.g. remove, revert):
mozilla other
status -nmcd 'glob:**' 1.77 4.10 sec
debugpathcomplete -f -n 0.53 1.26
debugpathcomplete -n 0.17 0.41
("-f" means "complete full paths", rather than the current directory)
Tracked files matching "a":
mozilla other
status -nmcd 'glob:a**' 0.26 0.47
debugpathcomplete -f -n a 0.10 0.24
debugpathcomplete -n a 0.10 0.22
We should be able to further improve completion performance once
the critbit work lands. Right now, our performance is limited by
the need to iterate over all keys in the dirstate.
$ hg init
$ echo "nothing" > a
$ hg add a
$ hg commit -m ancestor
$ echo "something" > a
$ hg commit -m branch1
$ hg co 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo "something else" > a
$ hg commit -m branch2
created new head
$ hg merge 1
merging a
warning: conflicts during merge.
merging a incomplete! (edit conflicts, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
[1]
$ hg id
32e80765d7fe+75234512624c+ tip
$ cat a
<<<<<<< local
something else
=======
something
>>>>>>> other
$ hg status
M a
? a.orig