namespaces: add nodemap property
This patch adds a node-to-name map property to the namespace. This is necessary
because we cannot simply invert the name-to-node map because we do not assume
the name-to-node map to be unique (for example, consider named branches: many
nodes have one branch name).
The node-to-name is helpful in log commands where we are already iterating over
a set of nodes and want to display some kind of naming information to the user.
$ hg init
$ echo This is file a1 > a
$ hg add a
$ hg commit -m "commit #0"
$ echo This is file b1 > b
$ hg add b
$ hg commit -m "commit #1"
$ hg update 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo This is file c1 > c
$ hg add c
$ hg commit -m "commit #2"
created new head
$ hg merge 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ rm b
$ echo This is file c22 > c
Test hg behaves when committing with a missing file added by a merge
$ hg commit -m "commit #3"
abort: cannot commit merge with missing files
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