Make alias-choosing code generic so GA can be fully automated

This means that when 4.2 is GA, our update automation should pick it up automatically, and update `latest` and `4` to point to it.

generate-stackbrew-library.sh

@@ -1,10 +1,6 @@
 #!/usr/bin/env bash
 set -Eeuo pipefail
 
-declare -A aliases=(
-	[4.1]='4 latest'
-	[3.13]='3'
-)
 defaultVariant='ubuntu'
 
 self="$(basename "$BASH_SOURCE")"
@@ -14,7 +10,7 @@ if [ "$#" -eq 0 ]; then
 	versions="$(jq -r '
 		to_entries
 		# sort version numbers with highest first
-		| sort_by(.key | split("[.-]"; "") | map(try tonumber // .))
+		| sort_by(.key | split("[.-]"; "") | map(tonumber? // .))
 		| reverse
 		| map(if .value then .key | @sh else empty end)
 		| join(" ")
@@ -81,6 +77,8 @@ join() {
 	echo "${out#$sep}"
 }
 
+declare -A usedAliases=()
+
 for version; do
 	export version
 	rcVersion="${version%-rc}"
@@ -103,16 +101,22 @@ for version; do
 	versionAliases=()
 	if [ "$version" = "$rcVersion" ]; then
 		while [ "$fullVersion" != "$version" -a "${fullVersion%[.-]*}" != "$fullVersion" ]; do
-			versionAliases+=( $fullVersion )
+			versionAliases+=( "$fullVersion" )
 			fullVersion="${fullVersion%[.-]*}"
 		done
 	else
-		versionAliases+=( $fullVersion )
+		versionAliases+=( "$fullVersion" )
+	fi
+	versionAliases+=( $version )
+
+	if [ "$version" = "$rcVersion" ]; then
+		for tagAlias in "${fullVersion%%.*}" latest; do
+			if [ -z "${usedAliases[$tagAlias]:-}" ]; then
+				versionAliases+=( "$tagAlias" )
+				usedAliases["$tagAlias"]="$version"
+			fi
+		done
 	fi
-	versionAliases+=(
-		$version
-		${aliases[$version]:-}
-	)
 
 	for variant in ubuntu alpine; do
 		dir="$version/$variant"

versions.json

@@ -53,6 +53,7 @@
     "version": "4.1.3"
   },
   "4.1-rc": null,
+  "4.2": null,
   "4.2-rc": {
     "alpine": {
       "version": "3.22"

versions.sh

@@ -96,7 +96,6 @@ for version in "${versions[@]}"; do
 		if [[ "$fullVersion" == "$rcFullVersion"* ]] || [ "$latestVersion" = "$rcFullVersion" ]; then
 			# "x.y.z-rc1" == x.y.z*
 			echo >&2 "warning: skipping/removing '$version' ('$rcVersion' is at '$rcFullVersion' which is newer than '$fullVersion')"
-			json="$(jq <<<"$json" -c '.[env.version] = null')"
 			continue
 		fi
 	fi
@@ -184,6 +183,16 @@ for version in "${versions[@]}"; do
 			}
 		'
 	)"
+
+	# make sure RCs and releases have corresponding pairs
+	json="$(jq <<<"$json" -c '
+		.[
+			env.rcVersion
+			+ if env.version == env.rcVersion then
+				"-rc"
+			else "" end
+		] //= null
+	')"
 done
 
 jq <<<"$json" -S . > versions.json