fix(stream): reads should emit the dataset number for each dataset (#2628)

* 🐛 streaming reads should emit the dataset number for each dataset

* 👌 attend to PR commentary

* 👌 rename test fixture file, as per PR request

* 🚨 run prettier -w on test-multi-result-streaming.test.cjs

* ⚗️ try latest mysql

* ⚗️ enable GHA for this branch, hopefully

* 🐛 no need to process.exit(0) in the test if the connection is properly destroyed

* ⏪ revert addition of this branch as a trigger

* ⏪ revert mysql version update

* 🚨 pacify the linter

* ci: debug multilpe stream test order

---------

Co-authored-by: Davyd McColl <[email protected]>

Author: wellwelwel

lib/commands/query.js

@@ -251,7 +251,7 @@ class Query extends Command {
     if (this.onResult) {
       this._rows[this._resultIndex].push(row);
     } else {
-      this.emit('result', row);
+      this.emit('result', row, this._resultIndex);
     }
     return Query.prototype.row;
   }
@@ -268,11 +268,11 @@ class Query extends Command {
     stream._read = () => {
       this._connection && this._connection.resume();
     };
-    this.on('result', row => {
+    this.on('result', (row, resultSetIndex) => {
       if (!stream.push(row)) {
         this._connection.pause();
       }
-      stream.emit('result', row); // replicate old emitter
+      stream.emit('result', row, resultSetIndex); // replicate old emitter
     });
     this.on('error', err => {
       stream.emit('error', err); // Pass on any errors

test/integration/test-multi-result-streaming.test.cjs

@@ -0,0 +1,55 @@
+'use strict';
+
+const { assert } = require('poku');
+const { createConnection } = require('../common.test.cjs');
+
+(async () => {
+  const conn = createConnection({ multipleStatements: true });
+  const captured1 = [];
+  const captured2 = [];
+  const sql1 =
+    'select * from information_schema.columns order by table_schema, table_name, column_name limit 1;';
+  const sql2 =
+    'select * from information_schema.columns order by table_schema, table_name, ordinal_position limit 1;';
+
+  await conn.promise().query('set global max_allowed_packet=524288000');
+
+  const compare1 = await conn.promise().query(sql1);
+  const compare2 = await conn.promise().query(sql2);
+
+  if (!compare1 || compare1.length < 1) {
+    assert.fail('no results for comparison 1');
+  }
+  if (!compare2 || compare2.length < 1) {
+    assert.fail('no results for comparison 2');
+  }
+
+  const stream = conn.query(`${sql1}\n${sql2}`).stream();
+  stream.on('result', (row, datasetIndex) => {
+    if (datasetIndex === 0) {
+      captured1.push(row);
+    } else {
+      captured2.push(row);
+    }
+  });
+  // note: this is very important:
+  // after each result set is complete,
+  // the stream will emit "readable" and if we don't
+  // read then 'end' won't be emitted and the
+  // test will hang.
+  stream.on('readable', () => {
+    stream.read();
+  });
+
+  await new Promise((resolve, reject) => {
+    stream.on('error', (e) => reject(e));
+    stream.on('end', () => resolve());
+  });
+
+  assert.equal(captured1.length, 1);
+  assert.equal(captured2.length, 1);
+  assert.deepEqual(captured1[0], compare1[0][0]);
+  assert.deepEqual(captured2[0], compare2[0][0]);
+
+  conn.end();
+})();