cext-revlog: fixed __delitem__ for uninitialized nodetree
This is a bug in a code path that's seldom used, because in practice
(at least in the whole test suite), calls to `del index[i:j]` currently
just don't happen before the nodetree has been initialized.
However, in our current work to replace the nodetree by a Rust implementation,
this is of course systematic.
In `index_slice_del()`, if the slice start is smaller than `self->length`,
the whole of `self->added` has to be cleared.
Before this change, the clearing was done only by the call to
`index_invalidate_added(self, 0)`, that happens only for initialized
nodetrees. Hence the removal was effective only from `start` to `self->length`.
The consequence is index corruption, with bogus results in subsequent calls,
and in particular errors such as `ValueError("parent out of range")`, due to
the fact that parents of entries in `self->added` are now just invalid.
This is detected by the rebase tests, under conditions that the nodetree
of revlog.c is never initialized. The provided specific test is more direct.
Differential Revision: https://phab.mercurial-scm.org/D7603
--- a/mercurial/cext/revlog.c Wed Nov 20 13:03:22 2019 -0500
+++ b/mercurial/cext/revlog.c Thu Dec 05 20:41:23 2019 +0100
@@ -2522,7 +2522,10 @@
index_invalidate_added(self, 0);
if (self->ntrev > start)
self->ntrev = (int)start;
+ } else if (self->added) {
+ Py_CLEAR(self->added);
}
+
self->length = start;
if (start < self->raw_length) {
if (self->cache) {
--- a/tests/test-parseindex2.py Wed Nov 20 13:03:22 2019 -0500
+++ b/tests/test-parseindex2.py Thu Dec 05 20:41:23 2019 +0100
@@ -247,6 +247,32 @@
got = index[-1]
self.assertEqual(want, got) # no inline data
+ def testdelitemwithoutnodetree(self):
+ index, _junk = parsers.parse_index2(data_non_inlined, False)
+
+ def hexrev(rev):
+ if rev == nullrev:
+ return b'\xff\xff\xff\xff'
+ else:
+ return nodemod.bin('%08x' % rev)
+
+ def appendrev(p1, p2=nullrev):
+ # node won't matter for this test, let's just make sure
+ # they don't collide. Other data don't matter either.
+ node = hexrev(p1) + hexrev(p2) + b'.' * 12
+ index.append((0, 0, 12, 1, 34, p1, p2, node))
+
+ appendrev(4)
+ appendrev(5)
+ appendrev(6)
+ self.assertEqual(len(index), 7)
+
+ del index[1:7]
+
+ # assertions that failed before correction
+ self.assertEqual(len(index), 1) # was 4
+ self.assertEqual(index.headrevs(), [0]) # gave ValueError
+
if __name__ == '__main__':
import silenttestrunner