tests/test-empty.t

phabricator: add a small language to query Differential Revisions

Previously, `phabread` can only be used to read a single patch, or a single
stack of patches. In the future, we want to have more complex queries like
filtering with status (open, accepted, closed, etc), or maybe more complex
like filtering by reviewers etc. The command line flag approach won't scale
with that.

Besides, we might want to have other commands to update Differential
Revision status in batch, like accepting a stack using a single command.

Therefore, this patch adds a small language. It has basic set operations:
`&`, `+`, `-` and an ancestor operator to support `--stack`.

Test Plan:
Try querying this Phabricator instance:

  hg phabread 1+2 # 1, 2
  hg phabread D2+D1 # 2, 1
  hg phabread ':118-115+:2-1' # 114, 116, 117, 118, 2
  hg phabread '((:118-(D115+117)))&:117' # 114, 116
  hg phabread ':2&:117' --debug # differential.query is called only once

Make sure the output is expected and prefetch works.

Differential Revision: https://phab.mercurial-scm.org/D125

Create an empty repo:

  $ hg init a
  $ cd a

Try some commands:

  $ hg log
  $ hg grep wah
  [1]
  $ hg manifest
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  0 files, 0 changesets, 0 total revisions

Check the basic files created:

  $ ls .hg
  00changelog.i
  requires
  store

Should be empty:

  $ ls .hg/store

Poke at a clone:

  $ cd ..
  $ hg clone a b
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd b
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  0 files, 0 changesets, 0 total revisions
  $ ls .hg
  00changelog.i
  hgrc
  requires
  store

Should be empty:

  $ ls .hg/store

  $ cd ..