annotate: increase refcount of each revisions correctly (issue3841) Before this patch, refcount (managed in "needed") of parents of each revisions in "visit" is increased, only when parent is not annotated yet (examined by "p not in hist"). But this causes less refcount of the revision like "A" in the tree below ("A" is assumed as the second parent of "C"): A --- B --- C \ / \-----/ Steps of annotation for "C" in this case are shown below: 1. for "C" 1.1 increase refcount of "B" 1.2 increase refcount of "A" (=> 1) 1.3 defer annotation for "C" 2. for "A" 2.1 annotate for "A" (=> put result into "hist[A]") 2.2 clear "pcache[A]" ("pcache[A] = []") 3. for "B" 3.1 not increase refcount of "A", because "A not in hist" is False 3.2 annotate for "B" 3.3 decrease refcount of "A" (=> 0) 3.4 delete "hist[A]", even though "A" is still needed by "C" 3.5 clear "pcache[B]" 4. for "C", again 4.1 not increase refcount of "B", because "B not in hist" is False 4.2 increase refcount of "A" (=> 1) 4.3 defer annotation for "C" 5. for "A", again 5.1 annotate for "A" (=> put result into "hist[A]", again) 5.2 clear "pcache[A]" 6. for "C", once again 6.1 not increase refcount of "B", because "B not in hist" is False 6.2 not increase refcount of "A", because "A not in hist" is False 6.3 annotate for "C" 6.4 decrease refcount of "A", and delete "hist[A]" 6.5 decrease refcount of "B", and delete "hist[B]" 6.6 clear "pcache[C]" At step (5.1), annotation for "A" mis-recognizes that all lines are created at "A", because "pcache[A]" already cleared at step (2.2) prevents from scanning ancestors of "A". So, annotation for "C" or its descendants loses information about "A" or its ancestors. The root cause of this problem is that refcount of "A" is decreased at step (3.3), even though it isn't increased at step (3.1). To increase refcount correctly, this patch increases refcount of each parents of each revisions: - regardless of "p not in hist" or not, and - only once for each revisions in "visit" (by "not pcached") In fact, this problem should occur only on legacy repositories in which a filelog includes the merging between the revision and its ancestor (as the second parent), because: - tree is scanned in depth-first without such merging, revisions in "visit" refer different revisions as parent each other - recent Mercurial doesn't allow such merging changelog and manifest can include such merging someway, but filelogs can't, because "localrepository._filecommit()" converts such merging request to linear history. This patch tests merging cases below: these cases are from filelog of "mercurial/commands.py" in the repository of Mercurial itself. - both parents are same 10 --- 11 --- 12 \_/ filelogrev: changesetid: 10 00ea3613f82c 11 fc4a6e5b5812 12 4f802588cdfb - the second parent is also ancestor of the first one 37 --- 38 --- 39 --- 40 \________/ filelogrev: changesetid: 37 f8d56da6ac8f 38 38919e1c254d 39 d3400605d246 40 f06a4a3b86a7

annotate: reuse already calculated annotation Before this patch, annotation is re-calculated even if it is already calculated. This may cause unexpected annotation, because already cleared "pcache" ("pcache[f] = []") prevents from scanning ancestors. This patch reuses already calculated annotation if it is available. In fact, "reusable" situation should be seen only on legacy repositories in which a filelog include the merging between the revision and its ancestor, because: - tree is scanned in depth-first without such merging, annotation result should be released soon - recent Mercurial doesn't allow such merging changelog and manifest can include such merging someway, but filelogs can't, because "localrepository._filecommit()" converts such merging request to linear history.

log: fix behavior with empty repositories (issue3497) Make output in this special case consistent with general case one.

merge with crew

revlog: don't cross-check ancestor result against Python version

parsers: a C implementation of the new ancestors algorithm The performance of both the old and new Python ancestor algorithms depends on the number of revs they need to traverse. Although the new algorithm performs far better than the old when revs are numerically and topologically close, both algorithms become slow under other circumstances, taking up to 1.8 seconds to give answers in a Linux kernel repo. This C implementation of the new algorithm is a fairly straightforward transliteration. The only corner case of interest is that it raises an OverflowError if the number of GCA candidates found during the first pass is greater than 24, to avoid the dual perils of fixnum overflow and trying to allocate too much memory. (If this exception is raised, the Python implementation is used instead.) Performance numbers are good: in a Linux kernel repo, time for "hg debugancestors" on two distant revs (24bf01de7537 and c2a8808f5943) is as follows: Old Python: 0.36 sec New Python: 0.42 sec New C: 0.02 sec For a case where the new algorithm should perform well: Old Python: 1.84 sec New Python: 0.07 sec New C: measures as zero when using --time (This commit includes a paranoid cross-check to ensure that the Python and C implementations give identical answers. The above performance numbers were measured with that check disabled.)

revlog: choose a consistent ancestor when there's a tie Previously, we chose a rev based on numeric ordering, which could cause "the same merge" in topologically identical but numerically different repos to choose different merge bases. We now choose the lexically least node; this is stable across different revlog orderings.

ancestor: a new algorithm that is faster for nodes near tip Instead of walking all the way to the root of the DAG, we generate a set of candidate GCA revs, then figure out which ones will win the race to the root (usually without needing to traverse all the way to the root). In the common case of nodes that are close to each other in both revision number and topology, this is usually a big win: it makes "hg --time debugancestors" up to 9 times faster than the more general ancestor function when measured on heads of the linux-2.6 hg repo. Victory is not assured, however. The older function can still win by a large margin if one node is much closer to the root than the other, or by a much smaller amount if one is an ancestor of the other. For now, we've also got a small paranoid harness function that calls both ancestor functions on every input and ensures that they give equivalent answers. Even without the checker function, the old ancestor function needs to stay alive for the time being, as its generality is used by context.filectx.merge.

update: allow dirty update to foreground (successors) Update to "foreground" are no longer seen as cross branch update. "Foreground" are descendants or successors (or successors of descendants (or descendant of successors (etc))). This allows to update with uncommited changes that get automatically merged. This changeset is a small step forward. We want to allow dirty update to "background" (precursors) and takes obsolescence in account when finding the default update destination. But those requires deeper changes and will comes in later changesets.

obsolete: extract foreground computation from bookmark.validdest This foreground logic will be reused by update logic.