commands: make commit acquire locks before processing (issue4368) Before this patch, "hg commit" (process A) executes steps below: 1. get current branch heads via 'repo.branchheads()' - cache 'repo.changelog' 2. invoke 'repo.commit()' 3. acquire wlock - invalidate 'repo.dirstate' 4. access 'repo.dirstate' - re-read '.hg/dirstate' - check validity of parent revisions with 'repo.changelog' 5. invoke 'repo.commitctx()' 6. acquire store lock (slock) - invalidate 'repo.changelog' 7. do committing 8. release slock 9. release wlock 10. check new branch head (via 'cmdutil.commitstatus()') If acquisition of wlock at (3) above waits for another "hg commit" (process B) or so running parallelly to release wlock, process A causes creating orphan revision, because: - '.hg/dirstate' refers the revision, which is newly added by process B, as its parent - but already cached 'repo.changelog' doesn't contain such revision - therefore, validating parents of '.hg/dirstate' at (4) above replaces such revision with 'nullid' Then, process A creates "orphan" revision, of which parent is "null" revision. In addition to it, "created new head" may be shown at the end of process A unintentionally, if store is updated parallelly, because both getting branch heads (1) and checking new branch head (10) are executed outside slock scope. To avoid this issue, this patch makes "hg commit" acquire wlock and slock before processing. This patch resolves the issue between "hg commit" processes, but not one between "hg commit" and other commands. Subsequent patches resolve the latter. Even after this patch, there are still corner case problems below: - filecache may overlook changes of '.hg/dirstate', and it causes similar issue (see below for detail) https://bz.mercurial-scm.org/show_bug.cgi?id=4368#c10 - 3rd party extension may cause similar issue, if it directly uses 'repo.commit()' without acquisition of wlock and slock This can be fixed by acquisition of slock at the beginning of 'repo.commit()', but it seems suitable for "default" branch In fact, acquisition of slock itself is already introduced at "default" branch by 4414d500604f, but acquisition is not at the beginning of 'repo.commit()'. This patch also changes some tests: - test-fncache.t needs this tricky wrapping, to release (= forced failure of) wlock certainly - order of "hg commit" output is changed by widening scope of locks, because some hooks are fired after releasing wlock

addrevision: use general delta when the incoming base delta is bad We unify the delta selection process to be a simple three options process: - try to use the incoming delta (if lazydeltabase is on) - try to find a suitable parents to delta against (if gd is on) - try to delta against the tipmost revision The first of this option that yield a valid delta will be used. The test change in 'test-generaldelta.t' show this behavior as we use a delta against the parent instead of a full delta when the incoming delta is not suitable. This as some impact on 'test-bundle.t' because a delta somewhere changes. It does not seems to change the test semantic and have been ignored.

test: use a bigger manifest in general delta test The currently used manifest is too small and cannot sustain a chain length above "1". This make testing the 'lazybasedelta' behavior hard. So we add an extra file in the manifest to help testing in the next changeset. The semantic of existing tests have been checked and is not changed.