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.

tweakdefaults: make hg resolve require --re-merge flag to re-merge Pulkit suggested it in https://phab.mercurial-scm.org/D4379, and a discussion with Octobus people reminded me that people still use the error-prone default behavior of `hg resolve`. Differential Revision: https://phab.mercurial-scm.org/D6610

unshelve: rename _dounshelve() to dounshelve() This is a follow-up patch to 3de4f17f4824. Differential Revision: https://phab.mercurial-scm.org/D6605

rust: remove Deref in favor of explicit methods Differential Revision: https://phab.mercurial-scm.org/D6593

rust: simplify overly complicated expression Differential Revision: https://phab.mercurial-scm.org/D6592

rust: run rfmt on all hg-core/hg-cpython code Differential Revision: https://phab.mercurial-scm.org/D6591

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.

changelog: fix handling of empty copy entries in changeset Before this patch, when an empty value was found in the changeset, we would get a ValueError, which would result in None being returned for addedfiles/removedfiles and p1copies/p2copies. That made 278dcb24e535 (copies: write empty entries in changeset when also writing to filelog, 2019-04-23) ineffective at helping the read path not look for copies in the filelogs. Differential Revision: https://phab.mercurial-scm.org/D6595