make mq play nicely with the branch cache
- if no patches are applied, don't do anything different
- if the cache includes valid data from one of the patch revisions,
use the cache, but don't save anything new
- if the cache has data from before the patch revisions only,
save what the list of branches would be without the patch revisions
# mq patch on an empty repo
tip: 0
No .hg/branches.cache
tip: 0
No .hg/branches.cache
# some regular revisions
Patch queue now empty
tip: 1
3f910abad313ff802d3a23a7529433872df9b3ae 1
3f910abad313ff802d3a23a7529433872df9b3ae bar
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo
# add some mq patches
applying p1
Now at: p1
tip: 2
3f910abad313ff802d3a23a7529433872df9b3ae 1
3f910abad313ff802d3a23a7529433872df9b3ae bar
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo
tip: 3
3f910abad313ff802d3a23a7529433872df9b3ae 1
3f910abad313ff802d3a23a7529433872df9b3ae bar
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo
branch foo: 3
branch bar: 2
# removing the cache
tip: 3
3f910abad313ff802d3a23a7529433872df9b3ae 1
3f910abad313ff802d3a23a7529433872df9b3ae bar
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo
branch foo: 3
branch bar: 2
# importing rev 1 (the cache now ends in one of the patches)
tip: 3
3f910abad313ff802d3a23a7529433872df9b3ae 1
3f910abad313ff802d3a23a7529433872df9b3ae bar
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo
branch foo: 3
branch bar: 2
qbase: 1
# detect an invalid cache
Patch queue now empty
applying p0
applying p1
applying p2
Now at: p2
tip: 3
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff 0
9539f35bdc80732cc9a3f84e46508f1ed1ec8cff foo