From 2c5f3df47d2737a823a13e44c330cbb138d05aa7 Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Tue, 9 Jul 2019 04:00:32 -0400
Subject: fix handling of errors from eval

---
 src/state.rs | 46 ++++++++++++++++++++++++++++------------------
 src/tui.rs   | 14 +++++++++-----
 2 files changed, 37 insertions(+), 23 deletions(-)

diff --git a/src/state.rs b/src/state.rs
index f6c8a78..d291e15 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -7,10 +7,8 @@ pub enum Error {
     #[snafu(display("invalid command index: {}", idx))]
     InvalidCommandIndex { idx: usize },
 
-    #[snafu(display("error sending message: {}", source))]
-    Sending {
-        source: futures::sync::mpsc::SendError<StateEvent>,
-    },
+    #[snafu(display("error sending message"))]
+    Sending,
 
     #[snafu(display("error printing output: {}", source))]
     PrintOutput { source: std::io::Error },
@@ -23,7 +21,7 @@ pub type Result<T> = std::result::Result<T, Error>;
 
 #[derive(Debug)]
 pub enum StateEvent {
-    Line(usize, String, futures::sync::oneshot::Sender<()>),
+    Line(usize, String, futures::sync::oneshot::Sender<Result<()>>),
 }
 
 pub struct State {
@@ -43,14 +41,21 @@ impl State {
         &mut self,
         idx: usize,
         line: &str,
-        res: futures::sync::oneshot::Sender<()>,
-    ) -> Result<()> {
-        snafu::ensure!(
-            !self.commands.contains_key(&idx),
-            InvalidCommandIndex { idx }
-        );
-        let eval = crate::eval::eval(line).context(Eval)?;
-        self.commands.insert(idx, Command::new(eval, res));
+        res: futures::sync::oneshot::Sender<Result<()>>,
+    ) -> std::result::Result<
+        (),
+        (futures::sync::oneshot::Sender<Result<()>>, Error),
+    > {
+        if self.commands.contains_key(&idx) {
+            return Err((res, Error::InvalidCommandIndex { idx }));
+        }
+        let eval = crate::eval::eval(line).context(Eval);
+        match eval {
+            Ok(eval) => {
+                self.commands.insert(idx, Command::new(eval, res));
+            }
+            Err(e) => return Err((res, e)),
+        }
         Ok(())
     }
 
@@ -115,7 +120,12 @@ impl State {
                     line,
                     res,
                 ))) => {
-                    self.eval(idx, &line, res)?;
+                    match self.eval(idx, &line, res) {
+                        Ok(()) => {}
+                        Err((res, e)) => {
+                            res.send(Err(e)).map_err(|_| Error::Sending)?;
+                        }
+                    }
                     did_work = true;
                 }
                 futures::Async::Ready(None) => {
@@ -155,8 +165,8 @@ impl State {
                             .remove(&idx)
                             .context(InvalidCommandIndex { idx })?
                             .res
-                            .send(())
-                            .map_err(|()| unreachable!())?;
+                            .send(Ok(()))
+                            .map_err(|_| Error::Sending)?;
                         did_work = true;
                     }
                     futures::Async::NotReady => {}
@@ -188,7 +198,7 @@ impl futures::future::Future for State {
 
 struct Command {
     future: crate::eval::Eval,
-    res: futures::sync::oneshot::Sender<()>,
+    res: futures::sync::oneshot::Sender<Result<()>>,
     cmd: Option<String>,
     args: Option<Vec<String>>,
     output: Vec<u8>,
@@ -198,7 +208,7 @@ struct Command {
 impl Command {
     fn new(
         future: crate::eval::Eval,
-        res: futures::sync::oneshot::Sender<()>,
+        res: futures::sync::oneshot::Sender<Result<()>>,
     ) -> Self {
         Self {
             future,
diff --git a/src/tui.rs b/src/tui.rs
index 6708340..221604d 100644
--- a/src/tui.rs
+++ b/src/tui.rs
@@ -8,8 +8,8 @@ pub enum Error {
     #[snafu(display("error during read: {}", source))]
     Read { source: crate::readline::Error },
 
-    #[snafu(display("error during eval: {}", source))]
-    Eval { source: crate::eval::Error },
+    #[snafu(display("error from state: {}", source))]
+    State { source: crate::state::Error },
 
     #[snafu(display("error during sending: {}", source))]
     Sending {
@@ -41,14 +41,14 @@ pub fn tui() {
                 })
                 .then(move |res| match res {
                     // successful run or empty input means prompt again
-                    Ok(_)
-                    | Err(Error::Eval {
+                    Ok(Ok(()))
+                    | Ok(Err(crate::state::Error::Eval {
                         source:
                             crate::eval::Error::Parser {
                                 source: crate::parser::Error::CommandRequired,
                                 ..
                             },
-                    }) => Ok(futures::future::Loop::Continue(idx + 1)),
+                    })) => Ok(futures::future::Loop::Continue(idx + 1)),
                     // eof means we're done
                     Err(Error::Read {
                         source: crate::readline::Error::EOF,
@@ -59,6 +59,10 @@ pub fn tui() {
                         error(&e);
                         Ok(futures::future::Loop::Continue(idx + 1))
                     }
+                    Ok(Err(e)) => {
+                        error(&Error::State { source: e });
+                        Ok(futures::future::Loop::Continue(idx + 1))
+                    }
                 })
         })
     }));
-- 
cgit v1.2.3-54-g00ecf