stream: Don't stop reading on zero-length decoded output

Fixes regression introduced in 7e1cf84c9e

lib/_stream_readable.js

@@ -291,9 +291,6 @@ function onread(stream, er, chunk) {
     return;
   }
 
-  if (state.decoder)
-    chunk = state.decoder.write(chunk);
-
   // at this point, if we got a zero-length buffer or string,
   // and we're not in object-mode, then there's really no point
   // continuing.  it means that there is nothing to read right
@@ -305,6 +302,9 @@ function onread(stream, er, chunk) {
       0 === chunk.length)
     return;
 
+  if (state.decoder)
+    chunk = state.decoder.write(chunk);
+
   // update the buffer info.
   state.length += state.objectMode ? 1 : chunk.length;
   state.buffer.push(chunk);

test/simple/test-stream2-readable-empty-buffer-no-eof.js

@@ -24,6 +24,10 @@ var assert = require('assert');
 
 var Readable = require('stream').Readable;
 
+test1();
+test2();
+
+function test1() {
   var r = new Readable();
 
   // should not end when we get a Buffer(0) or '' as the _read result
@@ -83,3 +87,32 @@ process.on('exit', function() {
     assert.deepEqual(results, [ 'xxxxx', 'xxxxx', 'EOF' ]);
     console.log('ok');
   });
+}
+
+function test2() {
+  var r = new Readable({ encoding: 'base64' });
+  var reads = 5;
+  r._read = function(n, cb) {
+    if (!reads--)
+      return cb(null, null); // EOF
+    else
+      return cb(null, new Buffer('x'));
+  };
+
+  var results = [];
+  function flow() {
+    var chunk;
+    while (null !== (chunk = r.read()))
+      results.push(chunk + '');
+  }
+  r.on('readable', flow);
+  r.on('end', function() {
+    results.push('EOF');
+  });
+  flow();
+
+  process.on('exit', function() {
+    assert.deepEqual(results, [ 'eHh4', 'eHg=', 'EOF' ]);
+    console.log('ok');
+  });
+}