rust-revlog: fix incorrect results with NULL_NODE prefixes...
rust-revlog: fix incorrect results with NULL_NODE prefixes
In case a short hash is a prefix of `NULL_NODE`, the correct revision
number lookup is `NULL_REVISION` only if there is no match in the nodemap.
Indeed, if there is a single nodemap match, then it is an ambiguity with the
always matching `NULL_NODE`.
Before this change, using the Mercurial development repository as a testbed (it
has public changesets with node ID starting with `0005` and `0009`), this is
what `rhg` did (plain `hg` provided for reference)
```
$ rust/target/debug/rhg cat -r 000 README
README: no such file in rev
000000000000
$ hg cat -r 000 README
abort: ambiguous revision identifier: 000
```
Here is the expected output for `rhg` on ambiguous prefixes (again, before
this change):
```
$ rust/target/debug/rhg cat -r 0001 README
abort: ambiguous revision identifier: 0001
```
The test provided by
8c29af0f6d6e in `test-rhg.t` could become flaky with
this change, unless all hashes are fixed. We expect reviewers to be more
sure about that than we are.
