fileset: add a lightweight file filtering language
This patch was inspired by one that Jun Wu authored for the fb-experimental
repo, to avoid using matcher for efficiency[1]. We want a way to specify what
files will be converted to LFS at commit time. And per discussion, we also want
to specify what files to skip, text diff, or merge in another config option.
The current `lfs.threshold` config option could not satisfy complex needs. I'm
putting it in a core package because Augie floated the idea of also using it for
narrow and sparse.
Yuya suggested farming out to fileset.parse(), which added support for more
symbols. The only fileset element not supported here is 'negate'. (List isn't
supported by filesets either.) I also changed the 'always' token to the 'all()'
predicate for consistency, and introduced 'none()' to improve readability in a
future tracked file based config. The extension operator was changed from '.'
to '**', to match how recursive path globs are specified. Finally, I changed
the path matcher from '/' to 'path:' at Yuya's suggestion, for consistency with
matcher. Unfortunately, ':' is currently reserved in filesets, so this has to
be quoted to be processed as a string instead of a symbol[2]. We should
probably revisit that, because it's seriously ugly. But it's only used by an
experimental extension, and I think using a file based config for LFS may drive
some more tweaks, so I'm settling for this for now.
I reserved all of the glob characters in fileset except '.' and '_' for the
extension test because those are likely valid extension characters.
Sample filter settings:
all() # everything
size(">20MB") # larger than 20MB
!**.txt # except for .txt files
**.zip | **.tar.gz | **.7z # some types of compressed files
"path:bin" # files under "bin" in the project root
[1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-December/109387.html
[2] https://www.mercurial-scm.org/pipermail/mercurial-devel/2018-January/109729.html
$ hg init
$ echo foo > foo
$ echo bar > bar
$ hg ci -qAm 'add foo bar'
$ echo foo2 >> foo
$ echo bleh > bar
$ hg ci -m 'change foo bar'
$ hg up -qC 0
$ hg mv foo foo1
$ echo foo1 > foo1
$ hg cat foo >> foo1
$ hg ci -m 'mv foo foo1'
created new head
$ hg merge
merging foo1 and foo to foo1
1 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg debugstate --nodates
m 0 -2 unset bar
m 0 -2 unset foo1
copy: foo -> foo1
$ hg st -q
M bar
M foo1
Removing foo1 and bar:
$ cp foo1 F
$ cp bar B
$ hg rm -f foo1 bar
$ hg debugstate --nodates
r 0 -1 set bar
r 0 -1 set foo1
copy: foo -> foo1
$ hg st -qC
R bar
R foo1
Re-adding foo1 and bar:
$ cp F foo1
$ cp B bar
$ hg add -v foo1 bar
adding bar
adding foo1
$ hg debugstate --nodates
n 0 -2 unset bar
n 0 -2 unset foo1
copy: foo -> foo1
$ hg st -qC
M bar
M foo1
foo
Reverting foo1 and bar:
$ hg revert -vr . foo1 bar
saving current version of bar as bar.orig
reverting bar
saving current version of foo1 as foo1.orig
reverting foo1
$ hg debugstate --nodates
n 0 -2 unset bar
n 0 -2 unset foo1
copy: foo -> foo1
$ hg st -qC
M bar
M foo1
foo
$ hg diff
Merge should not overwrite local file that is untracked after remove
$ rm *
$ hg up -qC
$ hg rm bar
$ hg ci -m 'remove bar'
$ echo 'memories of buried pirate treasure' > bar
$ hg merge
bar: untracked file differs
abort: untracked files in working directory differ from files in requested revision
[255]
$ cat bar
memories of buried pirate treasure
Those who use force will lose
$ hg merge -f
other [merge rev] changed bar which local [working copy] deleted
use (c)hanged version, leave (d)eleted, or leave (u)nresolved? u
merging foo1 and foo to foo1
0 files updated, 1 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
[1]
$ cat bar
bleh
$ hg st
M bar
M foo1