relnotes: copy "next" to "5.1" and clear "next" To avoid merge conflicts, we want to avoid modifying the file on multiple branches in parallel. This patch is therefore meant to be applied to the stable branch and then quickly be merged to default (at least before edits are made to relnotes/next there). Another option would have been to copy the file on the stable branch and to clear it on the default branch. However, that still results in conflicts if the copy is edited on the stable branch (Mercurial would try to apply the changes from the default branch to it). We could also delete the file in one commit and recreate it in another commit. However, Mercurial is quite inconsistent in what it considers a break in history (see test-copies-unrelated.t), so I'd like to avoid that. Differential Revision: https://phab.mercurial-scm.org/D6705

upgrade: introduce a _copyrevlog method This function copies a revlog from the old store to the new one, without re-adding all deltas manually. This will eventually save a lot of time when some revlog does not needs any conversions. Code actually using this will be introduced in later changesets.

upgrade: rename `_copyrevlogs` to `_clonerevlogs` The underlying revlog method is named `clone`, keeping the naming consistent seems clearer. This is motivated to clarify the difference with an (upcoming) function that simply copy revlog files as is.

upgrade: walk the source store file only once I don't expect this to have a significant performance impact, but it seems simpler and saner to do the operation only once and to keep the result around.

upgrade: always use full text if "full-add" mode is enable We should not be using a delta since the goal is to perform a full addition from scratch in all cases. Without this patch, `hg debugupgraderepo --optimize re-delta-fulladd --run` can crash.

byteify-strings: fix misalignment with multi-line parenthesis This improves the current fix to also take into account cases where the last line ended on the opening `(`, `[` or `{` and adds a regression test.

byteify-strings: add test for byteify-strings.py This tests the basic features expected from this script, some cases may not be covered yet. A future patch will demonstrate an issue with multi-line `(`, `[` and `{` alignment and propose a fix.

merge with stable

automation: push changes affecting .hgtags When I went to build the 5.1 tag using the in-repo automation, the automatic version calculation failed to deduce the clean 5.1 version string because we had only pushed the changeset corresponding to the 5.1 tag and not the changeset containing the 5.1 tag. So from the perspective of the remote repo, the 5.1 tag didn't exist yet and automatic version deduction failed. This commit changes the `hg push` to also push all changesets affecting the .hgtags file, ensuring the remote has up-to-date tags information. I tested this by creating a local draft changeset with a dummy tag value on a different DAG head and instructed the automation to build a revision that didn't have this change to .hgtags. The tag was successfully pushed and the built package had a version number incorporating that tag. Sending this to stable so the 5.1.1 automation hopefully "just works."

byteify-strings: add cli argument to handle `attr*()` when they are methods Certain code bases have useful utils that wrap the builtin functions, and are called like `util.setattr`.