Chained otherwise never ends

[apaleslimghost]

When you chain 3 or more .otherwises, i.e. σ.otherwise(ρ).otherwise(τ), and ρ is the only nonempty stream, the resulting stream doesn't ever send any data.

This pull request so far just adds a failing test, I'm having a look at fixing it.

[apaleslimghost]

Ok, a minimal test case is that any stream that does a redirect can't be otherwise'd, for example:

var σ = require('./lib');

var xs = σ(function(push, next) {
    next(σ([1, 2, 3]));
});

xs.otherwise(σ([])).toArray(σ.log);

You'd expect [1,2,3] but nothing ever gets logged.

[caolan]

@quarterto thanks for reporting. I can confirm I'm seeing this behaviour.

[vqvu]

I think what's happening here is that the second redirect that's done by otherwise is redirecting to the wrong stream (xs instead of <the stream to which xs redirects>). Streams probably need to keep track of the streams to which they delegate for possible later use.

Something like this:

diff --git a/lib/index.js b/lib/index.js
index c5060f1..379e8b6 100755
--- a/lib/index.js
+++ b/lib/index.js
@@ -371,6 +371,7 @@ function Stream(/*optional*/xs, /*optional*/ee, /*optional*/mappingHint) {
     this._observers = [];
     this._destructors = [];
     this._send_events = false;
+    this._delegate = null;
     this.source = null;

     // Old-style node Stream.pipe() checks for this
@@ -847,6 +848,10 @@ Stream.prototype._redirect = function (to) {
     // coerce to Stream
     to = _(to);

+    while (to._delegate) {
+        to = to._delegate;
+    }
+
     to._consumers = this._consumers.map(function (c) {
         c.source = to;
         return c;
@@ -866,6 +871,8 @@ Stream.prototype._redirect = function (to) {
         this.pause();
         to._checkBackPressure();
     }
+
+    this._delegate = to;
 };

 /**

[apaleslimghost]

@vqvu your patch passes the tests, want me to commit it, or you wanna start a new pull request?

[vqvu]

Feel free to incorporate it into your pull request.
On Jul 8, 2014 2:38 AM, "Matt Brennan" notifications@github.com wrote:

@vqvu https://github.com/vqvu your patch passes the tests, want me to
commit it, or you wanna start a new pull request?

—
Reply to this email directly or view it on GitHub
#104 (comment).

[apaleslimghost]

Tests fail on Node 0.11 but it's not related to this pull request.

[caolan]

Wow, great work you two, not an easy one to spot ;) 🍻