release 4.2.0

doc/CHANGELOG.md

@@ -9,8 +9,15 @@ Versions follow `MAJOR.MINOR.PATCH-REVISION_STAGE_N` (e.g. `3.99.1-4_rc_1`).
 
 ## [Unreleased]
 
+---
+
+## [4.2.0] — 2026-10-13
+
 ### Added
 
+- `backtrace`, `locale_check` and `get_pkgmgr` answer `-h` / `--help`, and are
+  listed (with `error` and `set_colors`) in the README functions table and in
+  `help`.
 - `pkgi` (install) and `pkgr` (uninstall, with `-p`/`--purge` and `-d`/`--deps`)
   commands for apt, dnf/yum, zypper, pacman, apk, portage, xbps and nix; both
   accept `-y`/`--yes` and `-n`/`--dry-run` and use `sudo` (or `doas`) when needed.
@@ -32,6 +39,9 @@ Versions follow `MAJOR.MINOR.PATCH-REVISION_STAGE_N` (e.g. `3.99.1-4_rc_1`).
 
 ### Fixed
 
+- `locale_check` without argument failed under `set -u`.
+- Copyright years: `processes.sh` (2013-2022) updated, the license block added
+  to the two bash-completion scripts.
 - `taz`: a plain file with the `tar` format could be deleted instead of being
   archived; existing `<item>.tar` files are no longer overwritten; trailing
   slashes, `.`/`..` and names starting with `-` are handled; the `gzip`

doc/CONTRIBUTING.md

@@ -108,7 +108,10 @@ brew install shellcheck
   environment. Prefer upper case for global and lowercase for local.
 - **`printf`** instead of `echo` all the time.
 - **Never `eval`** — use namerefs (`local -n`), `${!varname}` indirection, or
-  `declare -g` instead.
+  `declare -g` instead. The only exception is the function generator of
+  `build_locale_shortcuts` (`profile.d/lang.sh`): bash cannot create a function
+  whose name is only known at run time otherwise, and the only value injected
+  into it is quoted with `printf %q`.
 - **No hardcoded defaults** — wire every configurable value through
   `${VAR:-default}` and document the key in `profile.conf` and `README.md §4`.