dirstate-v2: Replace the 32-bit `mode` field with two bits Previously we stored the entire value from `stat_result.st_mode`, like dirstate-v1 does. However only the executable permission and type of file (only symbolic links and normal files are supported) are relevant to Mecurial. So replace this field with two bits in the existing bitfield byte. For now the unused space is left as padding, as it will be used for something else soon. Differential Revision: https://phab.mercurial-scm.org/D11635

dirstate-v2: Store unsigned integers inside DirstateEntry The negative marker values are not used anymore. Differential Revision: https://phab.mercurial-scm.org/D11634

dirstate-v2: Truncate directory mtimes to 31 bits of seconds … instead of 64 bits, while keeping the sub-second presision. This brings the size of one timestamp from 12 bytes to 8 bytes. 31 bits is chosen instead of 32 because that’s already what happens for the mtime of files and symlinks, because dirstate-v1 uses negative i32 values as markers. Later we’ll add sub-second precision for file/symlink mtimes, making their dirstate-v2 representation the same as for directories. Differential Revision: https://phab.mercurial-scm.org/D11633

dirstate-v2: Separate Rust structs for Timestamp and PackedTimestamp PackedTimestamp is now exclusively for dirstate-v2 serialization purpose. It contains unaligned big-endian integers. Timestamp is used everywhere else and contains native Rust integers. Differential Revision: https://phab.mercurial-scm.org/D11632

dirstate-v2: Change the representation of negative directory mtime Change it from how I previously thought C’s `timespec` works to how it actually works. The previous behavior was also buggy for timestamps strictly before the epoch but less than one second away from it, because two’s complement does not distinguish negative zero from positive zero. Differential Revision: https://phab.mercurial-scm.org/D11629

dirstate-v2: Only convert from SystemTime to Timestamp and not back Converting from Timestamp back to SystemTime was only used for equality comparison, but this can also be done on Timestamp values. Differential Revision: https://phab.mercurial-scm.org/D11631

dirstate-v2: Swap the order of size and mtime on disk This makes the dirstate-v2 file format match dirstate-v1 for the order of `mode`, `size`, and `mtime`. This order does not matter as long as these components are handled through named fields/attributes in code, but in a few places we still have tuples so having the same order everywhere might help avoid a bug that might not be obvious since those components have the same type. Differential Revision: https://phab.mercurial-scm.org/D11620

dirstate-v2: Document flags/mode/size/mtime fields of tree nodes This file format modification was previously left incomplete because of planned upcoming changes. Not all of these changes have been made yet, but documenting what exists today will help talking more widely about it. Differential Revision: https://phab.mercurial-scm.org/D11625

help: update help text for debug-repair-issue6528 The changegroup fix was put in 5.9.1, this is now out of date. Alson, this can maybe encourage people to upgrade? Differential Revision: https://phab.mercurial-scm.org/D11392

dispatch: use detailed exit code 250 for keyboard interrupt Among our users at Google, we're still seeing several percent of commands fail with exit code 255. I suspect keyboard interrupts is an important remaining reason. This is a resend of D10086 with some fixes for pager handling added ahead of it. Differential Revision: https://phab.mercurial-scm.org/D11628