The 5th batch

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/RelNotes/2.56.0.adoc

@@ -43,6 +43,11 @@ UI, Workflows & Features
    output has been optimized to reserve a column for marks (caret,
    question mark, or asterisk) only when such marks are actually shown.
 
+ * Option parsing with 'git rev-parse --parseopt' and in most 'git'
+   subcommands has been updated to exit with 0 (instead of 129) when the
+   help option ('-h' or '--help') is requested directly by the user,
+   aligning with standard Unix convention.
+
 
 Performance, Internal Implementation, Development Support etc.
 --------------------------------------------------------------
@@ -108,6 +113,56 @@ Performance, Internal Implementation, Development Support etc.
    the generated header file 'hook-list.h' is built before compiling
    files in 'builtin_sources' that depend on it.
 
+ * The repository discovery and repository configuration phases, which
+   were previously intertwined in 'setup.c', have been split.  Repository
+   discovery has been updated to populate a 'struct repo_discovery'
+   without modifying the repository state, which is then taken by
+   repository configuration to initialize the repository, paving the way
+   for clean unification of repository configuration.
+
+ * The 'SubmittingPatches' document has been updated to explicitly
+   describe the expectation for contributors to retract or abandon their
+   patch series when they are no longer pursuing it.
+
+ * The contributor guide has been updated to advise new contributors to
+   trim irrelevant quoted text when replying to review comments, matching
+   the existing advice given to reviewers.
+
+ * The build system has been updated to support building universal macOS
+   binaries when 'Rust' is enabled, by compiling separate static archives
+   for each target triple listed in 'RUST_TARGETS' and combining them
+   using the macOS 'lipo' tool.  The 'git-credential-osxkeychain' helper
+   has been updated to link against '$(RUST_LIB)' when 'Rust' is enabled.
+
+ * The test suite has been updated to use the 'test_grep' helper instead
+   of bare 'grep' for test assertions, allowing file contents to be
+   printed on failure for easier debugging.  A new 'greplint' linter has
+   been introduced to detect and prevent new bare 'grep' assertions from
+   being added to the test suite.
+
+ * The pipelines in 't1410-reflog.sh' have been replaced with the
+   'test_stdout_line_count' helper to avoid suppressing the exit code of
+   'git' commands, ensuring failures are not hidden from the test suite.
+
+ * The cache-scanning loop in 'next_cache_entry()' has been optimized
+   to avoid rescanning already-unpacked index entries, preventing a
+   quadratic performance slow-down when diffing the working tree
+   against a commit with a pathspec matching early index entries.
+
+ * The global configuration variable 'ignore_case' (representing the
+   'core.ignorecase' configuration) has been migrated into 'struct
+   repo_config_values' to tie it to a specific repository instance.
+
+ * The performance of ref updates and reads using the 'reftable' backend
+   in the presence of many deletion tombstone records has been optimized
+   by removing the tombstone suppression flag from the merged iterator
+   and instead skipping tombstones at higher-level call sites where
+   iteration bounds are known.
+
+ * Various code paths have been hardened against potential NULL-pointer
+   dereferences and invalid file descriptor accesses flagged by
+   Coverity.
+
 
 Fixes since v2.55
 -----------------
@@ -215,3 +270,31 @@ Fixes since v2.55
    escape sequences that use colon-separated subfields (e.g., for
    256-color or true-color codes).
    (merge 3792b2aea4 mm/sideband-ansi-sgr-colon-fix later to maint).
+
+ * The 'reftable' code has been hardened against corrupted tables by
+   fixing out-of-bounds writes, out-of-bounds reads, and abort calls
+   during parsing.
+   (merge ca93c27328 ps/reftable-hardening later to maint).
+
+ * A description in the release notes for Git 2.55.0 has been
+   retroactively updated to clarify that Rust support is enabled by
+   default, but still optional, and will become mandatory in Git 3.0.
+   (merge 18b2009d14 jc/relnotes-2.55-rust-fix later to maint).
+
+ * The early-exit optimization in 'paint_down_to_common()' has been
+   gated on the queue being generation-ordered, fixing a bug where
+   'git merge-base' (without '--all') could return incorrect results
+   on repositories with v1 commit graphs and clock skew.
+   (merge ae68032a8d kk/commit-reach-find-all-fix later to maint).
+
+ * The client-side parser of the server-advertised bundle-URI list has
+   been updated to drain the remaining response in order to avoid
+   protocol desynchronization when the server sends a misconfigured list.
+   Also, the server-side has been taught to omit empty configuration
+   values instead of sending invalid key-value lines.
+   (merge 50de1169e4 tc/bundle-uri-empty-fix later to maint).
+
+ * The 'topo_levels' slab was propagated only to the topmost layer of a
+   split commit-graph chain, causing topological levels for commits in
+   base layers to be recomputed during incremental writes.  This has been
+   corrected.