repoview: bypass changelog method to computed cache key Getting the data necessary for the cache key using the changelog/revlog method adds a significant overhead. Given how simple the underlying implementation is and often this code is ran, it makes sense to violate layering and directly compute the data. Testing `hg log` on Mozilla-central, this reduce the time spent on changelog cache validation by an extra half: before: 12.2s of 69s after: 6.1s of 62s Total speed up from this patch and it's parent is 3x (With stupid python profiler overhead) The global speedup without profiler overhead is still there, Before: 51s After: 39s (-23%)

repoview: stop recomputing cached key in all case As explained in the comment, we were computing the key of the cache value every time because of some obscure MQ test failure. I've dropped that code and ran the test again that failure is gone. I assume some transaction cleanup got rid of it. So we are dropping that code. This provide a significant speedup. Testing `hg log` on Mozilla-central this reduce the time spent on changelog cache validation by a third: before: 19.5s of 80s after: 12.2s of 69s (With stupid python profiler overhead)

commands.debugindexdot: use cmdutil.openrevlog() This pattern is used for all the other debug* commands that operate on revlogs. debugindexdot is an outlier. Make it conform.

commands: unify argument handling for revlog debug commands The same 3 options are used in a few locations and I'm about to add another. Might as well consolidate the pattern.

commit: fix rest syntax of examples This fixes the formatting of help/commit page and silence test-gendoc.t.

ui: optionally ignore sub-options from configitems() For convenience.

ui: add method to return option and all sub-options Apparently ":" has been blessed as a generic separator for options and sub-options. We formalize this by introducing an API for obtaining an option and all its sub-options. This will be used in a subsequent patch for declaring sub-options for [paths].

revlog: don't consider nullrev when choosing delta base In the most complex case, we try using the incoming delta base, then we try both parents, and then we try the previous revlog entry. If none of these result in a good delta, we natually use the null revision as base. However, we sometimes consider the nullrev before we have exhausted our other options. Specifically, when both parents are null, we use the nullrev as delta base if it produces a good delta (according to _isgooddelta()), and we fail to try the previous revlog entry as delta base. After 20a9226bdc8a (addrevision: use general delta when the incoming base delta is bad, 2015-12-01), it can also happen for non-merge commits when the incoming delta is not good. The Firefox repo (from many months back) shrinks a tiny bit with this patch: from 1.855GB to 1.830GB (1.4%). The hg repo itself shrinks even less: by less than 0.1%. There may be repos that get larger instead. This undoes the unexplained test change in 20a9226bdc8a.

revlog: make calls to _isgooddelta() consistent We always want to call _isgooddelta() before accepting a delta. We mostly call the function right after building the delta, but not always. Instead, we have an extra call at the end of the big code block. Let's make it consistent, so we call _isgooddelta() right after builddelta() and exactly once per delta. That also lets us rely on "delta is None" to mean we didn't find a good delta.

revlog: clarify which revision is added to 'tested' when using cached delta The tested delta revisions are added to the 'tested' set. These are the same revisions we pass to builddelta(). However, in one case, we add builddelta(rev)[3] to the set intead of adding 'rev' itself. In that particular case, that element is the same as the function's input revision (because self._generaldelta is true), so the effect is the same. Still, let's just add the function's input revision to avoid confusing future readers.