fix: Invalid/Dangling completion after updating input (#4072)

src/widgets/helper/ResizingTextEdit.hpp

@@ -24,6 +24,11 @@ public:
 
     void setCompleter(QCompleter *c);
     QCompleter *getCompleter() const;
+    /**
+     * Resets a completion for this text if one was is progress.
+     * See `completionInProgress_`.
+     */
+    void resetCompletion();
 
 protected:
     int heightForWidth(int) const override;
@@ -41,6 +46,24 @@ private:
     QString textUnderCursor(bool *hadSpace = nullptr) const;
 
     QCompleter *completer_ = nullptr;
+    /**
+     * This is true if a completion was done but the user didn't type yet,
+     * and might want to press `Tab` again to get the next completion
+     * on the original text.
+     *
+     * For example:
+     *
+     * input: "pog"
+     * `Tab` pressed:
+     *   - complete to "PogBones"
+     *   - retain "pog" for next completion
+     *   - set `completionInProgress_ = true`
+     * `Tab` pressed again:
+     *   - complete ["pog"] to "PogChamp"
+     *
+     * [other key] pressed - updating the input text:
+     *   - set `completionInProgress_ = false`
+     */
     bool completionInProgress_ = false;
 
     bool eventFilter(QObject *obj, QEvent *event) override;