revlog: use a symbolic constant for the deltas/text ration We are about to use it somewhere else, we should as well make it easier to access and change.

revlog: do not search for delta for empty content We won't find any useful base to store an empty text. So we should not even try to.

revlog: split and document good delta conditional The logic is still identical, but having each conditional on its own helps to document them and will help to edit them in the future.

revlog: skip over empty revision when looking for delta base There is no point in keeping an empty revision in the middle of a chain since they won't contribute any data. So we filter them out when looking for a valid base delta.

debugrevlog: display details about empty revision We now display details about the course of emptiness (empty text or empty delta).

debugrevlog: track empty revlog entries A revlog entry can be "empty" for two reasons: * the stored text is empty * we found another entry with the exact same content Tracking them separately make revlog content clearer.

debugrevlog: document some of the variable used This help to understand the code.

revlog: drop compatibility for `revlog.descendant` (API) As advertised, the method is dropped in 4.8.

context: drop compatibility for `context.descendant` (API) As advertised, the method is dropped in 4.8.

cmdutil: remove _updatecleanmsg() which is no longer used anywhere

cmdutil: fix weird indent in _mergemsg()

cext: fix a warning about differing const qualifiers on Windows The prototype takes a 'void *', but self->offsets is a 'const char **'. mercurial/cext/revlog.c(2011) : warning C4090: 'function' : different 'const' qualifiers

cext: fix most truncation warnings in revlog on Windows There's one more, and I'm not sure why it isn't being tripped on other platforms: mercurial/cext/revlog.c(430) : warning C4244: '=' : conversion from 'Py_ssize_t' to 'char', possible loss of data

cext: fix Windows warning about implicit conversion of 32-bit shift to 64 bit mercurial/cext/revlog.c(1541) : warning C4334: '<<' : result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift int ended?)

index: make capacity argument to nt_init be measured in revisions The nodetree's internal capacity field is measures in nodetree nodes, which is not something the caller should have to know about. Differential Revision: https://phab.mercurial-scm.org/D4166

index: avoid duplicating capacity-growth expression We were duplicating the "*2" instead of reusing it. It's overflow-safe to reuse as long as the growth factor (i.e. currently 2) is not larger than sizeof(nodetreenode) (currently 64 or 128). Differential Revision: https://phab.mercurial-scm.org/D4165

index: move check for too large capacity into nt_init() It's clearer to have the check just before the allocation happens. Differential Revision: https://phab.mercurial-scm.org/D4164

shortest: don't include nullid in disambigution revset As noted by Yuya in the review of D4118, the fact that the nodetree always contains the nullid is not what we want for the disambiguation case. It's not what the pure version of the code does. Note that the updated test also passes before this patch, but it wouldn't have passed in native-code mode once we start using the nodetree for disambiguating nodeid prefixes. Differential Revision: https://phab.mercurial-scm.org/D4163

index: don't include nullid in the internal "length" field This is a follow-up to 781b2720d2ac (index: don't include nullid in len(), 2018-07-20). I intentionally didn't update the "index stats", so it will also not include the space for nullid after this patch. Differential Revision: https://phab.mercurial-scm.org/D4162

tests: add test coverage for revlogindex[-1] which was previously missing Differential Revision: https://phab.mercurial-scm.org/D4184

context: safegaurd from 'lx' being passed as file flag in manifest Follows up for d558e53cd6b619d5f671a7580513bfc66a398eac. Differential Revision: https://phab.mercurial-scm.org/D4259

debugcommands: urlerror only has a read() method in Python 2 Differential Revision: https://phab.mercurial-scm.org/D4258

debugcommands: get_method should always return a sysstr Differential Revision: https://phab.mercurial-scm.org/D4257

stringutil: if we get a memoryview in escapestr, coerce it to bytes Otherwise we get an exception. Sadly, this manifesting deep inside the wireproto code, inside a future. For some reason the exception was /causing a hang/ rather than actually propagating out, which seems like it might merit some investigation in the future. Differential Revision: https://phab.mercurial-scm.org/D4256

debugcommands: fix a missing b prefix This wasn't causing any immediate problems because of the source transformer, but I noticed the inconsistency and it bugged me. # skip-blame just a b prefix Differential Revision: https://phab.mercurial-scm.org/D4255

wireprotohelpers: add missing b prefixes # skip-blame just b prefixes Differential Revision: https://phab.mercurial-scm.org/D4254

util: fix signature of setsockopt in socket observer The format string expected the result, callers all passed the result, but we didn't actually accept the result to this function. I swear I've looked at this code a dozen times trying to find the problem, and it was this simple all along. Differential Revision: https://phab.mercurial-scm.org/D4253

tests: port test-glog.t to Python 3 by using extracted printrevset Differential Revision: https://phab.mercurial-scm.org/D4252

tests: extract printrevset extension from test-glog-beautifygraph.t Differential Revision: https://phab.mercurial-scm.org/D4251

tests: add missing b'' prefix in test-check-code.t It now passes on Python 3. # skip-blame b prefix Differential Revision: https://phab.mercurial-scm.org/D4250