http2: add compat support for nested array headers

writeHead supports an array of arrays containing header name and values.
Compatibility between http2 & http1 even though this is not documented.
Fixes: #24466
PR-URL: #24665
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

Author: sebdeckers

lib/internal/http2/compat.js

@@ -574,10 +574,16 @@ class Http2ServerResponse extends Stream {
 if(headers===undefined&&typeofstatusMessage==='object')
 headers=statusMessage;
 
-if(typeofheaders==='object'){
+vari;
+if(Array.isArray(headers)){
+for(i=0;i<headers.length;i++){
+constheader=headers[i];
+this[kSetHeader](header[0],header[1]);
+}
+}elseif(typeofheaders==='object'){
 constkeys=Object.keys(headers);
 letkey='';
-for(vari=0;i<keys.length;i++){
+for(i=0;i<keys.length;i++){
 key=keys[i];
 this[kSetHeader](key,headers[key]);
 }

test/parallel/test-http2-compat-serverresponse-writehead-array.js

@@ -0,0 +1,42 @@
+'use strict';
+
+constcommon=require('../common');
+if(!common.hasCrypto)
+common.skip('missing crypto');
+constassert=require('assert');
+consth2=require('http2');
+
+// Http2ServerResponse.writeHead should support nested arrays
+
+constserver=h2.createServer();
+server.listen(0,common.mustCall(()=>{
+constport=server.address().port;
+server.once('request',common.mustCall((request,response)=>{
+response.writeHead(200,[
+['foo','bar'],
+['ABC',123]
+]);
+response.end(common.mustCall(()=>{server.close();}));
+}));
+
+consturl=`http://localhost:${port}`;
+constclient=h2.connect(url,common.mustCall(()=>{
+constheaders={
+':path': '/',
+':method': 'GET',
+':scheme': 'http',
+':authority': `localhost:${port}`
+};
+constrequest=client.request(headers);
+request.on('response',common.mustCall((headers)=>{
+assert.strictEqual(headers.foo,'bar');
+assert.strictEqual(headers.abc,'123');
+assert.strictEqual(headers[':status'],200);
+},1));
+request.on('end',common.mustCall(()=>{
+client.close();
+}));
+request.end();
+request.resume();
+}));
+}));