Summary:
New optional mode. If you set 'base' in local, project or global config or pass '--base' to 'arc diff' or 'arc which', it switches to DSL mode.
In DSL mode, lists of rules from args, local, project and global config are resolved, in that order. Rules can manipulate the rule machine or resolve into actual commits. Provides support for some 'arc' rules (mostly machine manipulation) and 'git' rules (symbolic ref and merge-base).
Test Plan:
Ran unit tests. Also:
```$ arc which --show-base --base 'arc:prompt'
Against which commit? HEAD
HEAD
$ arc which --show-base --base 'git:HEAD'
HEAD
$ arc which --show-base --base 'git:fake'
Usage Exception: None of the rules in your 'base' configuration matched a valid commit. Adjust rules or specify which commit you want to use explicitly.
$ arc which --show-base --base 'git:origin/master'
origin/master
$ arc which --show-base --base 'git:upstream'
Usage Exception: None of the rules in your 'base' configuration matched a valid commit. Adjust rules or specify which commit you want to use explicitly.
$ arc which --show-base --base 'literal:derp'
derp
$ arc which --show-base --base 'arc:halt'
Usage Exception: None of the rules in your 'base' configuration matched a valid commit. Adjust rules or specify which commit you want to use explicitly.
$ arc set-config --local base git:origin/master
Set key 'base' = 'git:origin/master' in local config.
$ arc which --show-base
origin/master
$ arc which --show-base --base 'git:HEAD^'
HEAD^
$ arc which --show-base --base 'arc:yield, git:HEAD^'
origin/master
$ arc which --show-base --base 'arc:global, git:HEAD^'
HEAD^
$ arc which --show-base --base 'arc:global, git:merge-base(origin/master)'
3f4f8992fba8d1f142974da36a82bae900e247c0```
Reviewers: dschleimer, vrana
Reviewed By: dschleimer
CC: aran
Maniphest Tasks: T1233
Differential Revision: https://secure.phabricator.com/D2748
Summary:
We currently use the language "relative commit" or "relative local commit" to refer to the head of a commit range. I want to move toward callign this a "base commit", since I think that makes more sense. This moves us a small step in that direction.
The DSL stuff in T1233 also needs access to this stuff, so move it up to the base. This is mostly a bite-sized piece of the change in that diff.
Test Plan: Ran "arc which" in a couple of circumstances, read explanations.
Reviewers: dschleimer, vrana
Reviewed By: dschleimer
CC: aran
Maniphest Tasks: T1233
Differential Revision: https://secure.phabricator.com/D2747