tests: add tests and document expectations from visit_children_set in rust
The tests this patch are adding have the form of formal spec in
invariants::visit_children_set::holds,
and then a series of checks that all examples must satisfy this
formal spec.
I tried to make the spec consistent with how this function is used
and how it was originally conceived. This is in conflict with how it's
documented in Rust. Some of the implementations also fail to implement
this spec, which leads to bugs, in particular when complicated patterns
are used with `hg status`.
#testcases dirstate-v1 dirstate-v2
#if dirstate-v2
$ cat >> $HGRCPATH << EOF
> [format]
> use-dirstate-v2=1
> [storage]
> dirstate-v2.slow-path=allow
> EOF
#endif
$ rm -rf r
$ hg init r
$ cd r
$ mkdir d1
$ mkdir d2
$ touch d1/f d2/f
$ hg commit -Am '.'
adding d1/f
adding d2/f
$ echo 'syntax:re' >> .hgignore
$ echo '^d1$' >> .hgignore
$ hg commit -Am "ignore d1"
adding .hgignore
Now d1 is a directory that's both committed and ignored.
Untracked files in d2 are still shown, but ones in d1 are ignored:
$ touch d1/g
$ touch d2/g
$ RAYON_NUM_THREADS=1 hg status
? d2/g