context: make changectx.mutable() benefit from .phase() logic
This fixes "hg qimport -r null". Previous versions used to:
- Traceback because null revision mutability was not defined
- Add an empty -1.diff patch to the series
The error message:
abort: revision -1 is not mutable
is symptomatic of a deeper problem in phase command revision handling. It could
be fixed easily in the command itself but I feel a better fix must be done in
phase API which raises the issue of phase updates atomicity: aborting in
phases.advanceboundary/retractboundary requires a better rollback behaviour to
avoid partial changes.
$ HGENCODING=utf-8
$ export HGENCODING
$ try() {
> hg debugrevspec --debug $@
> }
$ log() {
> hg log --template '{rev}\n' -r "$1"
> }
$ hg init repo
$ cd repo
$ try 'p1()'
('func', ('symbol', 'p1'), None)
$ try 'p2()'
('func', ('symbol', 'p2'), None)
$ try 'parents()'
('func', ('symbol', 'parents'), None)
null revision
$ log 'p1()'
$ log 'p2()'
$ log 'parents()'
working dir with a single parent
$ echo a > a
$ hg ci -Aqm0
$ log 'p1()'
0
$ log 'tag() and p1()'
$ log 'p2()'
$ log 'parents()'
0
$ log 'tag() and parents()'
merge in progress
$ echo b > b
$ hg ci -Aqm1
$ hg up -q 0
$ echo c > c
$ hg ci -Aqm2
$ hg merge -q
$ log 'p1()'
2
$ log 'p2()'
1
$ log 'tag() and p2()'
$ log 'parents()'
1
2