meta: add a script to auto-update *_COMMIT and *_SHA256 envs

TODO.md

@@ -4,7 +4,6 @@ remove elements from this list as you see fit.
 
 * meta: do build virtualization without Docker, a la Void Linux
 * meta: describe Dockerfile gotchas and whatnot
-* meta: add a script to auto-update `*_COMMIT` and `*_SHA256` envs
 * meta: create a custom preprocessor to generate shell scripts
     * takes a sane syntax and transforms it into my fucked-up code style with `&&`s
 * meta: generate Dockerfiles too

auto-update

@@ -0,0 +1,48 @@
+#!/usr/bin/env sh
+
+note() {
+    local IFS=' '
+    printf '\033[1m%s\033[0m\n' "$*" >&2
+}
+
+investigate() {
+    url="${1?huh}"
+    [ "${url#"https://github.com/"}" = "$url" ] \
+    && re='/commit/' || re='/spoofed_commit_check/'
+    curl $curlflags "$url" | grep -F "$re" | grep -Eo '[0-9a-f]{40}'
+}
+
+set -- \
+cosmo           COSMO_COMMIT    https://github.com/jart/cosmopolitan \
+cosmo-kuroko    KUROKO_COMMIT   https://github.com/kuroko-lang/kuroko \
+cosmo-muon      MUON_COMMIT     https://git.sr.ht/~lattis/muon \
+cosmo-perl      PERL_COMMIT     https://github.com/G4Vi/perl5/tree/cosmo \
+cosmo-python    PYTHON_COMMIT   https://github.com/ahgamut/cpython/tree/cosmo_py311 \
+cosmo-yices     KISSAT_COMMIT   https://github.com/BrunoDutertre/kissat \
+cosmo-yices     YICES_COMMIT    https://github.com/SRI-CSL/yices2 \
+;
+
+me="$(readlink -f "$0")" && cd "${me%/*}" || exit
+curlflags="-L --no-progress-meter"
+any=0
+
+while [ $# != 0 ]; do
+    dir="$1" tag="$2" url="$3"
+    shift && shift && shift || { note 'not a multiple of 3!'; exit 255 ;}
+    ours="$(grep -F "$tag"= "$dir/Dockerfile" | grep -Eo '[0-9a-f]{40}' | head -n1)"
+    theirs="$(investigate "$url" | head -n1)"
+    if [ ${#theirs} == 0 ]; then
+        note "failed to retrieve update for $tag"
+    elif [ "$ours" != "$theirs" ]; then
+        any=1
+        note "updating $dir"
+        other="${tag%_COMMIT}_SHA256"
+        tgz="${url%/}"
+        tgz="${tgz%%/tree/*}"
+        tgz="$tgz/archive/$theirs.tar.gz"
+        sum="$(curl $curlflags "$tgz" | sha256sum - | awk '{print $1}')"
+        notwa-util/shed "$dir/Dockerfile" "s/$ours/$theirs/g"
+        notwa-util/shed "$dir/Dockerfile" "s/$other=.*/$other=$sum/g"
+    fi
+done
+[ $any = 1 ] || note "no new updates"