Enable prediction after backspace on prompt

plugins/c9.ide.terminal/predict_echo.js

@@ -495,8 +495,18 @@ define(function(require, exports, module) {
                 if (lastInput
                     && (state === STATE_WAIT_FOR_PROMPT_OR_ECHO)
                     && lastInput === data.substr(data.length - lastInput.length)
-                    && (!BASH_ONLY || isBashActive())
+                    && checkTextBeforePrediction()
-                    && checkTextBeforePrediction()) {
+                    && (!BASH_ONLY || isBashActive())) {
+                    if (DEBUG) console.log("  ^ re-enabled predictions:", lastInput);
+                    return startPredict();
+                }
+                
+                // Enable predictions when we see echoing *and* a prompt
+                if (lastInput
+                    && state == STATE_WAIT_FOR_PROMPT
+                    && lastInput === data.substr(data.length - lastInput.length)
+                    && checkTextBeforePrediction()
+                    && isBashActive()) {
                     if (DEBUG) console.log("  ^ re-enabled predictions:", lastInput);
                     return startPredict();
                 }

plugins/c9.ide.terminal/predict_echo_test.js

@@ -547,6 +547,18 @@ require(["lib/architect/architect", "lib/chai/chai", "/vfs-root", "ace/test/asse
                         
                     });
                 });
+                
+                it("recovers after spurious backspaces on a prompt", function(done) {
+                    predictor.once("nopredict", function() {
+                        predictor.once("nopredict", function() {
+                            assert.equal(session.$predictor.state, STATE_INITING);
+                            afterPrompt(done);
+                            send("\r");
+                        });
+                        send("Q");
+                    });
+                    send(INPUT_BACKSPACE);
+                });
             });
             
             if (!onload.remain) {