From 5ee0429bbbc6537b2e191d5ca780d0cbe1bc4b60 Mon Sep 17 00:00:00 2001
From: Richard Hinkamp <richard@hinkamp.nl>
Date: Wed, 9 Jun 2021 21:58:00 +0200
Subject: [PATCH] fix: handle double shutdown()

fixes #1005
---
 lib/log4js.js                 |  7 +++++++
 test/tap/fileAppender-test.js | 26 ++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/lib/log4js.js b/lib/log4js.js
index fdd48c84..7c2783ad 100644
--- a/lib/log4js.js
+++ b/lib/log4js.js
@@ -82,6 +82,13 @@ function configure(configurationFileOrObject) {
  *  as the first argument.
  */
 function shutdown(cb) {
+  if (!enabled) {
+    if (cb) {
+      cb(undefined);
+    }
+    return null;
+  }
+
   debug("Shutdown called. Disabling all log writing.");
   // First, disable all writing to appenders. This prevents appenders from
   // not being able to be drained because of run-away log writes.
diff --git a/test/tap/fileAppender-test.js b/test/tap/fileAppender-test.js
index be1791c2..1947568c 100644
--- a/test/tap/fileAppender-test.js
+++ b/test/tap/fileAppender-test.js
@@ -376,5 +376,31 @@ test("log4js fileAppender", batch => {
     t.end();
   });
 
+  batch.test("with double shutdown", async t => {
+    const testFile = path.join(__dirname, "fa-default-test.log");
+    await removeFile(testFile);
+
+    log4js.configure({
+      appenders: { test: { type: "file", filename: testFile } },
+      categories: { default: { appenders: ["test"], level: "trace" } }
+    });
+    const logger = log4js.getLogger("default-settings");
+
+    logger.info("1");
+    logger.info("2");
+    logger.info("3");
+
+    await new Promise(resolve => log4js.shutdown(resolve));
+    await new Promise(resolve => log4js.shutdown(resolve));
+    const fileContents = await fs.readFile(testFile, "utf8");
+    // 3 lines of output, plus the trailing newline.
+    t.equal(fileContents.split(EOL).length, 4);
+    t.match(
+      fileContents,
+      /\[\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}] \[INFO] default-settings - /
+    );
+    t.end();
+  });
+
   batch.end();
 });