From 48b851cd8af33315d079e88eccffbbd7e6ed38b8 Mon Sep 17 00:00:00 2001
From: Lucas Pickering <lucas@lucaspickering.me>
Date: Sun, 1 Sep 2024 09:07:48 -0400
Subject: [PATCH] Fix garbage events from vim

Vim dumps out some garbage events on exit, which causes strange behavior in Slumber.

Closes #351
---
 CHANGELOG.md                   |  1 +
 crates/slumber_tui/src/lib.rs  | 23 +++++++++++++++++------
 crates/slumber_tui/src/util.rs |  9 +++++++++
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f3bd7782..e8295af3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -49,6 +49,7 @@ Here's the full list of changes:
   - E.g. F5 will now refresh the collection while a text box is in focus
 - Redraw TUI when terminal is resized
 - Clamp text window scroll state when window is resized or text changes
+- Fix extraneous input events when exiting Vim [#351](https://github.com/LucasPickering/slumber/issues/351)
 
 ## [1.8.1] - 2024-08-11
 
diff --git a/crates/slumber_tui/src/lib.rs b/crates/slumber_tui/src/lib.rs
index aa7ef406..24ede414 100644
--- a/crates/slumber_tui/src/lib.rs
+++ b/crates/slumber_tui/src/lib.rs
@@ -18,7 +18,10 @@ mod view;
 use crate::{
     context::TuiContext,
     message::{Message, MessageSender, RequestConfig},
-    util::{get_editor_command, save_file, signals, ResultReported},
+    util::{
+        clear_event_buffer, get_editor_command, save_file, signals,
+        ResultReported,
+    },
     view::{PreviewPrompter, RequestState, View},
 };
 use anyhow::{anyhow, Context};
@@ -29,7 +32,7 @@ use crossterm::{
     },
     terminal::{EnterAlternateScreen, LeaveAlternateScreen},
 };
-use futures::{Future, StreamExt};
+use futures::StreamExt;
 use notify::{event::ModifyKind, RecursiveMode, Watcher};
 use ratatui::{prelude::CrosstermBackend, Terminal};
 use slumber_config::{Action, Config};
@@ -40,6 +43,7 @@ use slumber_core::{
     template::{Prompter, Template, TemplateChunk, TemplateContext},
 };
 use std::{
+    future::Future,
     io::{self, Stdout},
     ops::Deref,
     path::{Path, PathBuf},
@@ -418,11 +422,18 @@ impl Tui {
         self.terminal.draw(|frame| {
             frame.render_widget("Waiting for editor to close...", frame.area());
         })?;
+
+        let mut stdout = io::stdout();
+        crossterm::execute!(stdout, LeaveAlternateScreen)?;
         command.status().context(error_context)?;
-        // If the editor was terminal-based it probably dropped us out of the
-        // alternate screen when it closed, so get back in there. This is
-        // idempotent so no harm in doing it
-        crossterm::execute!(io::stdout(), EnterAlternateScreen)?;
+        // Some editors *cough* vim *cough* dump garbage to the event buffer on
+        // exit. I've never figured out what actually causes it, but a simple
+        // solution is to dump all events in the buffer before returning to
+        // Slumber. It's possible we lose some real user input here (e.g. if
+        // other events were queued behind the event to open the editor).
+        clear_event_buffer();
+        crossterm::execute!(stdout, EnterAlternateScreen)?;
+
         // Redraw immediately. The main loop will probably be in the tick
         // timeout when we go back to it, so that adds a 250ms delay to
         // redrawing the screen that we want to skip.
diff --git a/crates/slumber_tui/src/util.rs b/crates/slumber_tui/src/util.rs
index ddcd3935..454c85b5 100644
--- a/crates/slumber_tui/src/util.rs
+++ b/crates/slumber_tui/src/util.rs
@@ -4,6 +4,7 @@ use crate::{
     view::Confirm,
 };
 use anyhow::Context;
+use crossterm::event;
 use editor_command::EditorBuilder;
 use futures::{future, FutureExt};
 use slumber_core::{
@@ -15,6 +16,7 @@ use std::{
     ops::Deref,
     path::{Path, PathBuf},
     process::Command,
+    time::Duration,
 };
 use tokio::{fs::OpenOptions, io::AsyncWriteExt, sync::oneshot};
 use tracing::{debug, error, info, warn};
@@ -45,6 +47,13 @@ where
     }
 }
 
+/// Clear all input events in the terminal event buffer
+pub fn clear_event_buffer() {
+    while let Ok(true) = event::poll(Duration::from_millis(0)) {
+        let _ = event::read();
+    }
+}
+
 /// Listen for any exit signals, and return `Ok(())` when any signal is
 /// received. This can only fail during initialization.
 #[cfg(unix)]