fix: build and typecheck with postcss 8.5

packages/postcss-linaria/src/stringify.ts

@@ -384,7 +384,11 @@ class LinariaStringifier extends Stringifier {
     ) {
       return node.raws.linariaBetween;
     }
-    return super.raw(node, own, detect);
+    // postcss 8.5 declares the result as `boolean | string`, 8.4 as `string`.
+    // At runtime it is a boolean for the `semicolon` raw that the inherited
+    // `body` reads, so `string` is only the signature that the calls in this
+    // class rely on. The base result is returned unchanged.
+    return super.raw(node, own, detect) as string;
   }
 
   /** @inheritdoc */
@@ -400,7 +404,10 @@ class LinariaStringifier extends Stringifier {
       return `${node.raws[linariaProp]}`;
     }
 
-    return super.rawValue(node, prop);
+    // postcss 8.5 declares the result as `number | string`, 8.4 as `string`.
+    // The base result is returned unchanged; the fields read through
+    // `rawValue` (`params`, `value` and `selector`) are strings.
+    return super.rawValue(node, prop) as string;
   }
 
   /** @inheritdoc */

packages/server/src/collect.ts

@@ -93,7 +93,7 @@ export default function collect(
     let removedNodesFromOther = 0;
     criticalRule.each((childRule: ChildNode, index: number) => {
       if (isCritical(childRule)) {
-        otherRule.nodes[index - removedNodesFromOther]?.remove();
+        otherRule.nodes?.[index - removedNodesFromOther]?.remove();
         removedNodesFromOther += 1;
       } else {
         childRule.remove();
@@ -102,10 +102,10 @@ export default function collect(
 
     rule.remove();
 
-    if (criticalRule.nodes.length > 0) {
+    if (criticalRule.nodes?.length) {
       critical.append(criticalRule);
     }
-    if (otherRule.nodes.length > 0) {
+    if (otherRule.nodes?.length) {
       other.append(otherRule);
     }
   };

scripts/typecheck-postcss-8-5.sh

@@ -0,0 +1,56 @@
+#!/bin/sh
+# Typechecks the workspace packages that use postcss (@linaria/server,
+# @linaria/postcss-linaria and @linaria/atomic) against postcss 8.5.23.
+#
+# The committed manifests and lockfile still resolve postcss to 8.4.31, so the
+# script swaps in the ones of the dependabot update to 8.5.23, installs with
+# --ignore-scripts, runs `typecheck` of the three packages (`tsc --noEmit
+# --composite false`, after the declarations of their dependencies are built)
+# and puts the committed manifests, lockfile and install back on exit.
+#
+# Exit code: 0 when the packages typecheck, non-zero otherwise.
+set -eu
+
+# The head of the dependabot pull request that updates postcss to 8.5.23.
+update=05b0d4ca86d3cd33a46425ad124c6308be3531e0
+files="pnpm-lock.yaml packages/atomic/package.json packages/postcss-linaria/package.json packages/server/package.json"
+
+cd "$(dirname "$0")/.."
+
+git cat-file -e "$update^{commit}" || {
+  echo "commit $update is not in this repository" >&2
+  exit 2
+}
+
+# Plain output: the failure signature is matched against it.
+export NO_COLOR=1 FORCE_COLOR=0
+
+backup=$(mktemp -d)
+
+restore() {
+  status=$?
+  trap - EXIT
+  for file in $files; do
+    cp "$backup/$(echo "$file" | tr / _)" "$file"
+  done
+  rm -rf "$backup"
+  pnpm install --frozen-lockfile --ignore-scripts >/dev/null 2>&1 || true
+  exit "$status"
+}
+trap restore EXIT
+
+for file in $files; do
+  cp "$file" "$backup/$(echo "$file" | tr / _)"
+  git show "$update:$file" >"$file"
+done
+
+pnpm install --frozen-lockfile --ignore-scripts
+
+pnpm --filter ./packages/atomic --filter ./packages/postcss-linaria --filter ./packages/server list postcss --depth 0
+
+# --continue: report the errors of every package, not only of the first one
+# that fails.
+pnpm exec turbo run typecheck --force --continue \
+  --filter=@linaria/atomic \
+  --filter=@linaria/postcss-linaria \
+  --filter=@linaria/server