From c1112b6e75c9fa155fed9bf262ec489985cce414 Mon Sep 17 00:00:00 2001
From: Giovanni Campagna <gcampagn@cs.stanford.edu>
Date: Wed, 6 Oct 2021 17:53:44 -0700
Subject: [PATCH] Fix LGTM warnings

---
 lib/thingtalk-dialogues/synthesis-dialogue.ts | 21 +++++++++++++------
 lib/transaction-dialogues/context-phrases.ts  |  2 +-
 lib/transaction-dialogues/index.ts            |  1 -
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/lib/thingtalk-dialogues/synthesis-dialogue.ts b/lib/thingtalk-dialogues/synthesis-dialogue.ts
index ba86e6d71..eb14690e9 100644
--- a/lib/thingtalk-dialogues/synthesis-dialogue.ts
+++ b/lib/thingtalk-dialogues/synthesis-dialogue.ts
@@ -88,6 +88,17 @@ const enum PartialDialogueState {
  */
 let partialDialogueID = 0;
 
+/**
+ * Combine the id of the dialogue with the "tag" of the non-deterministic
+ * agent choice to form a single tag, used to identify contexts in the
+ * synthesis templates.
+ */
+function combineDialogueAgentTags(dialogueTag : number, agentTag : number) {
+    if (agentTag > 65535)
+        throw new Error('OVERFLOW: too many agent either choices');
+    return dialogueTag << 16 | agentTag;
+}
+
 /**
  * A partial dialogue, during synthesis.
  *
@@ -199,7 +210,7 @@ export default class SynthesisDialogue implements AbstractCommandIO, Synthesizer
             context: this,
             key: {
                 dialogue: this,
-                tag: this._id << 65536 | agentTurn.tag
+                tag: combineDialogueAgentTags(this._id, agentTurn.tag),
             }
         };
     }
@@ -278,12 +289,10 @@ export default class SynthesisDialogue implements AbstractCommandIO, Synthesizer
                                     placeholders : TemplatePlaceholderMap,
                                     semantics : SemanticAction<[Ast.DialogueState, ...any[]], Ast.DialogueState>) {
         let ctxNonTerm;
-        if (tag === null) {
+        if (tag === null)
             ctxNonTerm = new NonTerminal('ctx_sys_dynamic_any', undefined, ['dialogue', this]);
-        } else {
-            assert(tag < 65536);
-            ctxNonTerm = new NonTerminal('ctx_sys_dynamic_any', undefined, ['tag', this._id << 65536 | tag]);
-        }
+        else
+            ctxNonTerm = new NonTerminal('ctx_sys_dynamic_any', undefined, ['tag', combineDialogueAgentTags(this._id, tag)]);
 
         addTemplate(this._userGenerator, [ctxNonTerm], tmpl, placeholders, (ctx : AgentTurn, ...args : any[]) : UserReplyRecord|null => {
             const result = semantics(ctx.state, ...args);
diff --git a/lib/transaction-dialogues/context-phrases.ts b/lib/transaction-dialogues/context-phrases.ts
index bc01a6267..fa334c3e6 100644
--- a/lib/transaction-dialogues/context-phrases.ts
+++ b/lib/transaction-dialogues/context-phrases.ts
@@ -324,7 +324,7 @@ export class ContextPhraseCreator {
                 utterance.push(piece);
             }
 
-            if (utterance && utterance.length) {
+            if (utterance.length) {
                 const value = [this.ctx, bag];
                 output.push({
                     symbol: this.contextTable.ctx_thingpedia_list_result,
diff --git a/lib/transaction-dialogues/index.ts b/lib/transaction-dialogues/index.ts
index 62c4963bc..20a6ad64b 100644
--- a/lib/transaction-dialogues/index.ts
+++ b/lib/transaction-dialogues/index.ts
@@ -290,7 +290,6 @@ export async function policy(dlg : DialogueInterface, startMode : PolicyStartMod
             switch (cmd.type) {
             case POLICY_NAME + '.end':
                 dlg.say(dlg._("alright, {bye|good bye}!"), StateM.makeSimpleState(ctx.state, POLICY_NAME, 'sys_end'));
-                lastReply = await dlg.flush();
                 return;
 
             case POLICY_NAME + '.greet':