diff --git a/‎lib/zlib.js‎
Lines changed: 3 additions & 1 deletion b/‎lib/zlib.js‎
Lines changed: 3 additions & 1 deletion
diff --git a/‎test/parallel/test-zlib-decode-strings.js‎
Lines changed: 32 additions & 0 deletions b/‎test/parallel/test-zlib-decode-strings.js‎
Lines changed: 32 additions & 0 deletions
@@ -302,11 +302,13 @@ class ZlibBase extends Transform {
         );
       }
 
-      if (opts.encoding || opts.objectMode || opts.writableObjectMode) {
+      if (opts.encoding || opts.objectMode || opts.writableObjectMode ||
+          opts.decodeStrings === false) {
         opts = { ...opts };
         opts.encoding = null;
         opts.objectMode = false;
         opts.writableObjectMode = false;
+        opts.decodeStrings = true;
       }
     }
 
 
@@ -0,0 +1,32 @@
+'use strict';
+
+// Strings must be decoded before they reach the native handle, even when
+// decodeStrings: false is passed. This used to abort the process.
+
+const common = require('../common');
+const assert = require('assert');
+const zlib = require('zlib');
+
+const input = 'héllo wörld';
+
+const pairs = [
+  [zlib.createGzip, zlib.gunzipSync],
+  [zlib.createDeflate, zlib.inflateSync],
+  [zlib.createDeflateRaw, zlib.inflateRawSync],
+  [zlib.createBrotliCompress, zlib.brotliDecompressSync],
+  [zlib.createZstdCompress, zlib.zstdDecompressSync],
+];
+
+for (const [createCompress, decompressSync] of pairs) {
+  const compress = createCompress({ decodeStrings: false });
+  const chunks = [];
+  compress.on('data', (chunk) => chunks.push(chunk));
+  compress.on('end', common.mustCall(() => {
+    assert.strictEqual(decompressSync(Buffer.concat(chunks)).toString(), input);
+  }));
+  compress.end(input);
+}
+
+zlib.gzip(input, { decodeStrings: false }, common.mustSucceed((compressed) => {
+  assert.strictEqual(zlib.gunzipSync(compressed).toString(), input);
+}));
Original file line number	Diff line number	Diff line change
`@@ -302,11 +302,13 @@ class ZlibBase extends Transform {`
`302`	`302`	`);`
`303`	`303`	`}`
`304`	`304`
`305`		`- if (opts.encoding \|\| opts.objectMode \|\| opts.writableObjectMode) {`
	`305`	`+ if (opts.encoding \|\| opts.objectMode \|\| opts.writableObjectMode \|\|`
	`306`	`+ opts.decodeStrings === false) {`
`306`	`307`	`opts = { ...opts };`
`307`	`308`	`opts.encoding = null;`
`308`	`309`	`opts.objectMode = false;`
`309`	`310`	`opts.writableObjectMode = false;`
	`311`	`+ opts.decodeStrings = true;`
`310`	`312`	`}`
`311`	`313`	`}`
`312`	`314`