fix: disable use of thread-based worker getfixes() accesses to repo, changectx, filectx, etc., so I believe there are code paths triggering data race. Mercurial API isn't thread safe in general.

storage: also use `deltamode argument` for ifiledata Now that lower level uses such argument, we can propagate the change to higher layers.

configitems: rename the config to prevent adding an alias in future Right now the config option looks like: [experimental.server] stream-narrow-clones= which does not match how config options are generally defined in core. So let's rename this to: [experimental] server.stream-narrow-clones= before the new release so that we don't have to add an alias in future for this. Differential Revision: https://phab.mercurial-scm.org/D5198

sparse-revlog: only refine delta candidates in the sparse case (issue6006) Starting with 5aef5afa8654, a valid delta parent might be "refined". This allows repository using sparse-revlog to produce better delta chain by using better intermediate snapshot base. However, this refining step was performed in all cases, including for repository not using sparse-revlog. This could produce a strange chain in the general delta case and corrupted repository in the non-general delta case. We now skip this step unless sparse-revlog is in use. In issue 6006, Yuya Nishihara provided a test case using an external repository, so we did not include it. Finding "laboratory" condition to reproduce this case and implementing an efficient test reproducing it is a bit tricky. We do not foresee to have the time to provide one by the release date. Differential Revision: https://phab.mercurial-scm.org/D5197

changegroup: refactor emitrevision to use a `deltamode` argument This new argument gathers the semantic of `sendfulltext` and `deltaprevious` in a single value. We are about to introduce a new type of constraints. Avoiding yet another argument sounds like a plus.

http: work around custom http client classes that refuse extra attrs I have no idea what is going on with our custom http client code at Google, but it chokes on these extra attributes we're tucking on http clients. Since it feels more than a little wrong to just stuff extra data on a client, let's degrade gracefully when the client class refuses the attributes.

branchmap: do not specify changelog as an argument Since (unfiltered)repo.changelog lookup gets as fast as __dict__ lookup, there's no point to pass in changelog instance. $ hg perfbranchmap --clear-revbranch -R mozilla-central ! base (orig) wall 20.593091 comb 20.600000 user 20.520000 sys 0.080000 (best of 3) (this) wall 20.129126 comb 20.130000 user 20.020000 sys 0.110000 (best of 3) This backs out most of the changes in 76d4272bd57b and 47c03042cd1d.

filecache: unimplement __set__() and __delete__() (API) Implementing __set__() implies that the descriptor can't be overridden by obj.__dict__, which means any property access involves slow function call. "Data descriptors with __set__() and __get__() defined always override a redefinition in an instance dictionary. In contrast, non-data descriptors can be overridden by instances." https://docs.python.org/2.7/reference/datamodel.html#invoking-descriptors This patch basically backs out 236bb604dc39, "scmutil: update cached copy when filecached attribute is assigned (issue3263)." The problem described in issue3263 (which is #3264 in Bugzilla) should no longer happen since repo._bookmarkcurrent has been moved to repo._bookmarks.active. We still have a risk of introducing similar bugs, but I think that's the cost we have to pay. $ hg perfrevset 'branch(tip)' -R mercurial (orig) wall 0.139511 comb 0.140000 user 0.140000 sys 0.000000 (best of 66) (prev) wall 0.114195 comb 0.110000 user 0.110000 sys 0.000000 (best of 81) (this) wall 0.099038 comb 0.110000 user 0.100000 sys 0.010000 (best of 93)

filecache: use try-except for faster __dict__ lookup Python function call is slow, and the cost could be significant here. $ hg perfrevset 'branch(tip)' -R mercurial (orig) wall 0.139511 comb 0.140000 user 0.140000 sys 0.000000 (best of 66) (this) wall 0.114195 comb 0.110000 user 0.110000 sys 0.000000 (best of 81)

crecord: make nextsametype() check that parent item exists (issue6009) Items that represent files in curses interface don't have parents.