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
Test update logic when there are renames or weird same-name cases between dirs
and files
Update with local changes across a file rename
$ hg init r1 && cd r1
$ echo a > a
$ hg add a
$ hg ci -m a
$ hg mv a b
$ hg ci -m rename
$ echo b > b
$ hg ci -m change
$ hg up -q 0
$ echo c > a
$ hg up
merging a and b to b
warning: conflicts while merging b! (edit, 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
[1]
Test update when local untracked directory exists with the same name as a
tracked file in a commit we are updating to
$ hg init r2 && cd r2
$ echo root > root && hg ci -Am root # rev 0
adding root
$ echo text > name && hg ci -Am "name is a file" # rev 1
adding name
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkdir name
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test update when local untracked directory exists with some files in it and has
the same name a tracked file in a commit we are updating to. In future this
should be updated to give an friendlier error message, but now we should just
make sure that this does not erase untracked data
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkdir name
$ echo text > name/file
$ hg st
? name/file
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd ..
#if symlink
Test update when two commits have symlinks that point to different folders
$ hg init r3 && cd r3
$ echo root > root && hg ci -Am root
adding root
$ mkdir folder1 && mkdir folder2
$ ln -s folder1 folder
$ hg ci -Am "symlink to folder1"
adding folder
$ rm folder
$ ln -s folder2 folder
$ hg ci -Am "symlink to folder2"
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd ..
#endif
#if rmcwd
Test that warning is printed if cwd is deleted during update
$ hg init r4 && cd r4
$ mkdir dir
$ cd dir
$ echo a > a
$ echo b > b
$ hg add a b
$ hg ci -m "file and dir"
$ hg up -q null
current directory was removed
(consider changing to repo root: $TESTTMP/r1/r4)
#endif