From 28d5dd981873bfedbe4f650248813f333fe96451 Mon Sep 17 00:00:00 2001
From: "Michael B. Gale" <mbg@github.com>
Date: Wed, 14 Oct 2026 15:07:40 +0100
Subject: [PATCH] Revert "Allow logging functions to accept `string[]`
 directly"

This reverts commit 909fda1468f8ef25624848914b92c3faeba7cfe7.
---
 lib/entry-points.js  | 20 ++++----------------
 src/logging.test.ts  | 17 -----------------
 src/logging.ts       | 43 ++++++++-----------------------------------
 src/testing-utils.ts | 14 +++++++-------
 4 files changed, 19 insertions(+), 75 deletions(-)
 delete mode 100644 src/logging.test.ts

diff --git a/lib/entry-points.js b/lib/entry-points.js
index 8d6df2f78..e56668bbe 100644
--- a/lib/entry-points.js
+++ b/lib/entry-points.js
@@ -170475,24 +170475,12 @@ function fixCodeQualityCategory(logger2, category, env = getEnv()) {
 
 // src/logging.ts
 var core5 = __toESM(require_core());
-var joinMessageStrings = (message) => {
-  if (Array.isArray(message)) {
-    return message.join(" ");
-  } else {
-    return message;
-  }
-};
-var autoJoinMessageStrings = (fn) => {
-  return (message) => {
-    return fn(joinMessageStrings(message));
-  };
-};
 function getActionsLogger() {
   return {
-    debug: autoJoinMessageStrings(core5.debug),
-    info: autoJoinMessageStrings(core5.info),
-    warning: autoJoinMessageStrings(core5.warning),
-    error: autoJoinMessageStrings(core5.error),
+    debug: core5.debug,
+    info: core5.info,
+    warning: core5.warning,
+    error: core5.error,
     isDebug: core5.isDebug,
     startGroup: core5.startGroup,
     endGroup: core5.endGroup
diff --git a/src/logging.test.ts b/src/logging.test.ts
deleted file mode 100644
index 33f6f8c16..000000000
--- a/src/logging.test.ts
+++ /dev/null
@@ -1,17 +0,0 @@
-import test from "ava";
-
-import { joinMessageStrings } from "./logging";
-import { setupTests } from "./testing-utils";
-
-setupTests(test);
-
-test("joinMessageStrings", async (t) => {
-  // For strings and errors, it is the identity function.
-  t.deepEqual(joinMessageStrings("Hello"), "Hello");
-
-  const error = new Error("Some error");
-  t.deepEqual(joinMessageStrings(error), error);
-
-  // For arrays of strings, we get a join-ed string.
-  t.deepEqual(joinMessageStrings(["foo", "bar"]), "foo bar");
-});
diff --git a/src/logging.ts b/src/logging.ts
index 177aca6c7..2c34cb54d 100644
--- a/src/logging.ts
+++ b/src/logging.ts
@@ -1,16 +1,10 @@
 import * as core from "@actions/core";
 
-/** Types that all of our logging functions accept. */
-export type Loggable = string | string[];
-
-/** Some logging functions also accept errors directly. */
-export type LoggableError = Loggable | Error;
-
 export interface Logger {
-  debug: (message: Loggable) => void;
-  info: (message: Loggable) => void;
-  warning: (message: LoggableError) => void;
-  error: (message: LoggableError) => void;
+  debug: (message: string) => void;
+  info: (message: string) => void;
+  warning: (message: string | Error) => void;
+  error: (message: string | Error) => void;
 
   isDebug: () => boolean;
 
@@ -18,33 +12,12 @@ export interface Logger {
   endGroup: () => void;
 }
 
-/** If `message` is an array of strings, the array is `join`-ed into one string separated by spaces. */
-export const joinMessageStrings = <T>(
-  message: string[] | string | T,
-): string | T => {
-  if (Array.isArray(message)) {
-    return message.join(" ");
-  } else {
-    return message;
-  }
-};
-
-/**
- * Wraps a logging function so that `joinMessageStrings` is applied to the input before
- * calling the wrapped logging function.
- */
-const autoJoinMessageStrings = <T>(fn: (msg: string | T) => void) => {
-  return (message: string[] | string | T) => {
-    return fn(joinMessageStrings(message));
-  };
-};
-
 export function getActionsLogger(): Logger {
   return {
-    debug: autoJoinMessageStrings(core.debug),
-    info: autoJoinMessageStrings(core.info),
-    warning: autoJoinMessageStrings(core.warning),
-    error: autoJoinMessageStrings(core.error),
+    debug: core.debug,
+    info: core.info,
+    warning: core.warning,
+    error: core.error,
     isDebug: core.isDebug,
     startGroup: core.startGroup,
     endGroup: core.endGroup,
diff --git a/src/testing-utils.ts b/src/testing-utils.ts
index 4ff4d4934..d48f9e90f 100644
--- a/src/testing-utils.ts
+++ b/src/testing-utils.ts
@@ -30,7 +30,7 @@ import {
   featureConfig,
   FeatureEnablement,
 } from "./feature-flags";
-import { joinMessageStrings, Loggable, LoggableError, Logger } from "./logging";
+import { Logger } from "./logging";
 import { OverlayDatabaseMode } from "./overlay/overlay-database-mode";
 import { getBundlePlatform } from "./platform";
 import { ActionName } from "./status-report";
@@ -658,8 +658,8 @@ export class RecordingLogger implements Logger {
 
   constructor(private readonly logToConsole: boolean = true) {}
 
-  private addMessage(level: LogLevel, message: LoggableError): void {
-    this.messages.push({ type: level, message: joinMessageStrings(message) });
+  private addMessage(level: LogLevel, message: string | Error): void {
+    this.messages.push({ type: level, message });
 
     if (this.logToConsole) {
       // eslint-disable-next-line no-console
@@ -684,19 +684,19 @@ export class RecordingLogger implements Logger {
     return true;
   }
 
-  debug(message: Loggable) {
+  debug(message: string) {
     this.addMessage("debug", message);
   }
 
-  info(message: Loggable) {
+  info(message: string) {
     this.addMessage("info", message);
   }
 
-  warning(message: LoggableError) {
+  warning(message: string | Error) {
     this.addMessage("warning", message);
   }
 
-  error(message: LoggableError) {
+  error(message: string | Error) {
     this.addMessage("error", message);
   }