dirstate-item: add a `set_possibly_dirty` method
See inline documentation for details.
The pushes the AMBIGUOUS_TIME implementation further down the line within the
DirstateItem only. When this cleanup is done we will be able to stop using this
representation internally.
Differential Revision: https://phab.mercurial-scm.org/D11119
$ hg init
$ touch a
$ unset HGUSER
$ echo "[ui]" >> .hg/hgrc
$ echo "username= foo" >> .hg/hgrc
$ echo " bar1" >> .hg/hgrc
$ hg ci -Am m
adding a
abort: username 'foo\nbar1' contains a newline
[255]
$ rm .hg/hgrc
$ HGUSER=`(echo foo; echo bar2)` hg ci -Am m
adding a
abort: username 'foo\nbar2' contains a newline
[255]
$ hg ci -Am m -u "`(echo foo; echo bar3)`"
adding a
transaction abort!
rollback completed
abort: username 'foo\nbar3' contains a newline
[50]