posix: always seek to EOF when opening a file in append mode Python 3 already does this, so skip it there. Consider the program: #include <stdio.h> int main() { FILE *f = fopen("narf", "w"); fprintf(f, "narf\n"); fclose(f); f = fopen("narf", "a"); printf("%ld\n", ftell(f)); fprintf(f, "troz\n"); printf("%ld\n", ftell(f)); return 0; } on macOS, FreeBSD, and Linux with glibc, this program prints 5 10 but on musl libc (Alpine Linux and probably others) this prints 0 10 By my reading of https://pubs.opengroup.org/onlinepubs/009695399/functions/fopen.html this is technically correct, specifically: > Opening a file with append mode (a as the first character in the > mode argument) shall cause all subsequent writes to the file to be > forced to the then current end-of-file, regardless of intervening > calls to fseek(). in other words, the file position doesn't really matter in append-mode files, and we can't depend on it being at all meaningful unless we perform a seek() before tell() after open(..., 'a'). Experimentally after a .write() we can do a .tell() and it'll always be reasonable, but I'm unclear from reading the specification if that's a smart thing to rely on. This matches what we do on Windows and what Python 3 does for free, so let's just be consistent. Thanks to Yuya for the idea.

move: --force flag forcibly moves, not copies

copy: correct synopsis by making SOURCE a required argument

debugrevlog: fix average size computation for empty data (issue6167) If the file has no full snapshot (eg: was always empty), `hg debugrevlog` would fails when trying to compute their average size.

bookmarks: backout the attempt to fix the delete race This backs out 044045dce23a because it broke a bunch of tests on Windows. Yuya's theory is that we still rely on in-memory changelog data to be flushed out of the transaction.

help: add a missing blank line to unhide `revlog-compression` The help was output, but it was elided with "Enabled by default" from the previous item.

bookmarks: actual fix for race condition deleting bookmark This is a simple but efficient fix to prevent the issue tested in `test-bookmarks-corner-case.t`. It might be worth pursuing a more generic approach where filecache learn to depend on each other, but that would not be suitable for stable. The issue is complicated enough that I documented the race and its current solution as inline comment. See this comment for details on the fix.

localrepo: introduce a `_refreshchangelog` method See next changeset for usage and documentation for details.

bookmarks: actually trigger the race deleting bookmark in the test The previous committed version of the test did not triggered the race, but this was hidden by a strange behavior from the test runner. So we are moving the test to a slightly more complex that actually trigger the issue.

test: add some assert in the bookrace extension This cannot hurt to have a bit more security in the test extension.