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
#require no-msys # MSYS will translate web paths as if they were file paths
This tests if CGI files from before d0db3462d568 still work.
$ hg init test
$ cat >hgweb.cgi <<HGWEB
> #!$PYTHON
> #
> # An example CGI script to use hgweb, edit as necessary
>
> import cgitb, os, sys
> cgitb.enable()
>
> # sys.path.insert(0, "/path/to/python/lib") # if not a system-wide install
> from mercurial import hgweb
>
> h = hgweb.hgweb("test", "Empty test repository")
> h.run()
> HGWEB
$ chmod 755 hgweb.cgi
$ cat >hgweb.config <<HGWEBDIRCONF
> [paths]
> test = test
> HGWEBDIRCONF
$ cat >hgwebdir.cgi <<HGWEBDIR
> #!$PYTHON
> #
> # An example CGI script to export multiple hgweb repos, edit as necessary
>
> import cgitb, sys
> cgitb.enable()
>
> # sys.path.insert(0, "/path/to/python/lib") # if not a system-wide install
> from mercurial import hgweb
>
> # The config file looks like this. You can have paths to individual
> # repos, collections of repos in a directory tree, or both.
> #
> # [paths]
> # virtual/path = /real/path
> # virtual/path = /real/path
> #
> # [collections]
> # /prefix/to/strip/off = /root/of/tree/full/of/repos
> #
> # collections example: say directory tree /foo contains repos /foo/bar,
> # /foo/quux/baz. Give this config section:
> # [collections]
> # /foo = /foo
> # Then repos will list as bar and quux/baz.
>
> # Alternatively you can pass a list of ('virtual/path', '/real/path') tuples
> # or use a dictionary with entries like 'virtual/path': '/real/path'
>
> h = hgweb.hgwebdir("hgweb.config")
> h.run()
> HGWEBDIR
$ chmod 755 hgwebdir.cgi
$ . "$TESTDIR/cgienv"
$ $PYTHON hgweb.cgi > page1
$ $PYTHON hgwebdir.cgi > page2
$ PATH_INFO="/test/"
$ PATH_TRANSLATED="/var/something/test.cgi"
$ REQUEST_URI="/test/test/"
$ SCRIPT_URI="http://hg.omnifarious.org/test/test/"
$ SCRIPT_URL="/test/test/"
$ $PYTHON hgwebdir.cgi > page3
$ grep -i error page1 page2 page3
[1]