util: node v26.3.0 compat — styleText hex/validateStream, getCallSites, regexp highlighting, vm namespace, tty.WriteStream + deepEquals fixes (test-util 70% → 83%)

scripts/runner.node.mjs

@@ -758,6 +758,13 @@ async function runTests() {
           NO_COLOR: "1",
           BUN_DEBUG_QUIET_LOGS: "1",
         };
+        if (title.includes("test-util-styletext")) {
+          // These assert styleText's own color decisions, so neither the forced
+          // no-color settings above nor spawnBun's FORCE_COLOR may reach them.
+          env.FORCE_COLOR = undefined;
+          env.NO_COLOR = undefined;
+          env.NODE_DISABLE_COLORS = undefined;
+        }
         if (!isWindows && title.includes("/sequential/")) {
           // Sequential node tests share common.PORT (12346); a cluster worker
           // or child_process subprocess that outlives its test can keep that

src/js/builtins/UtilInspect.ts

@@ -5,6 +5,8 @@ export function getStylizeWithColor(inspect: Inspect) {
   return function stylizeWithColor(str: string, styleType: string) {
     const style = inspect.styles[styleType];
     if (style !== undefined) {
+      // inspect.styles.regexp is a function (highlightRegExp), not a color name.
+      if (typeof style === "function") return style(str);
       const color = inspect.colors[style];
       if (color !== undefined) return `\u001b[${color[0]}m${str}\u001b[${color[1]}m`;
     }