Feature: Better error handling/reporting (#1670)

* utils: re-export "anyhow" unconditionally

even for wasm targets.

* utils/errors: Share wasm-compatible code

and move everything that can't run in wasm into a separate submodule.

* utils: Share "errors" module unconditionally

The module is now structured such that all code incompatible with wasm
targets lives in its own submodule that isn't included when compiling
for wasm targets.

* utils/errors: Add "Help wanted" doc section

that informs the reader about the endeavour to improve error handling
throughout the zellij code base.

* plugins: Handle errors returned by `zellij_tile`

now that the panic calls have been removed.

* utils/errors: Extend `anyhow::Result` with traits

that allow for easy/concise logging of `anyhow::Result` types and
panicking the application when they are fatal or non-fatal.

* utils/errors: Fix doctest

* utils/errors: Add prelude

that applications can import to conveniently access the error handling
functionality part of the module. Re-exports some parts and macros from
anyhow and the `LoggableError` and `FatalError` traits.

* server/screen: Adopt error handling

and make all fallible functions from the public API return a `Result`.
Append error contexts in all functions that can come across error types
to allow tracing where an error originates and what lead there.

* server/lib: Catch errors from `screen`

and make them `fatal`. This will log the errors first, before unwrapping
on the error type and panicking the application.

* server/unit/screen: Fix unit tests

and unwrap on the `Result` types introduced from the new error handling.

* utils/errors: Track error source

in calls to `fatal`, so we keep track of the location where the panic
really originates. Otherwise, any call to `fatal` will show the code in
`errors` as source, which of course isn't true.
Also change the error formatting and do not call `to_log` for fatal
errors anymore, because the panic is already logged and contains much
more information.

* utils/errors: Update `FatalError` docs

* plugins: Undo accidental modifications

* utils/errors: Improve module docs

explain some error handling facilities and the motivation behind using
them.

* server/screen: Remove `Result` from Infallible

functions that are part of the public API.

1 files changed, 34 insertions, 32 deletions

diff --git a/zellij-server/src/unit/screen_tests.rs b/zellij-server/src/unit/screen_tests.rs
index 53cb62d1c..28aec39cb 100644
--- a/zellij-server/src/unit/screen_tests.rs
+++ b/zellij-server/src/unit/screen_tests.rs
@@ -114,11 +114,13 @@ fn create_new_screen(size: Size) -> Screen {
 
 fn new_tab(screen: &mut Screen, pid: i32) {
     let client_id = 1;
-    screen.new_tab(
-        LayoutTemplate::default().try_into().unwrap(),
-        vec![pid],
-        client_id,
-    );
+    screen
+        .new_tab(
+            LayoutTemplate::default().try_into().unwrap(),
+            vec![pid],
+            client_id,
+        )
+        .expect("TEST");
 }
 
 #[test]
@@ -150,7 +152,7 @@ pub fn switch_to_prev_tab() {
 
     new_tab(&mut screen, 1);
     new_tab(&mut screen, 2);
-    screen.switch_tab_prev(1);
+    screen.switch_tab_prev(1).expect("TEST");
 
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
@@ -169,8 +171,8 @@ pub fn switch_to_next_tab() {
 
     new_tab(&mut screen, 1);
     new_tab(&mut screen, 2);
-    screen.switch_tab_prev(1);
-    screen.switch_tab_next(1);
+    screen.switch_tab_prev(1).expect("TEST");
+    screen.switch_tab_next(1).expect("TEST");
 
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
@@ -189,7 +191,7 @@ pub fn close_tab() {
 
     new_tab(&mut screen, 1);
     new_tab(&mut screen, 2);
-    screen.close_tab(1);
+    screen.close_tab(1).expect("TEST");
 
     assert_eq!(screen.tabs.len(), 1, "Only one tab left");
     assert_eq!(
@@ -210,8 +212,8 @@ pub fn close_the_middle_tab() {
     new_tab(&mut screen, 1);
     new_tab(&mut screen, 2);
     new_tab(&mut screen, 3);
-    screen.switch_tab_prev(1);
-    screen.close_tab(1);
+    screen.switch_tab_prev(1).expect("TEST");
+    screen.close_tab(1).expect("TEST");
 
     assert_eq!(screen.tabs.len(), 2, "Two tabs left");
     assert_eq!(
@@ -232,8 +234,8 @@ fn move_focus_left_at_left_screen_edge_changes_tab() {
     new_tab(&mut screen, 1);
     new_tab(&mut screen, 2);
     new_tab(&mut screen, 3);
-    screen.switch_tab_prev(1);
-    screen.move_focus_left_or_previous_tab(1);
+    screen.switch_tab_prev(1).expect("TEST");
+    screen.move_focus_left_or_previous_tab(1).expect("TEST");
 
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
@@ -253,8 +255,8 @@ fn move_focus_right_at_right_screen_edge_changes_tab() {
     new_tab(&mut screen, 1);
     new_tab(&mut screen, 2);
     new_tab(&mut screen, 3);
-    screen.switch_tab_prev(1);
-    screen.move_focus_right_or_next_tab(1);
+    screen.switch_tab_prev(1).expect("TEST");
+    screen.move_focus_right_or_next_tab(1).expect("TEST");
 
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
@@ -273,17 +275,17 @@ pub fn toggle_to_previous_tab_simple() {
 
     new_tab(&mut screen, 1);
     new_tab(&mut screen, 2);
-    screen.go_to_tab(1, 1);
-    screen.go_to_tab(2, 1);
+    screen.go_to_tab(1, 1).expect("TEST");
+    screen.go_to_tab(2, 1).expect("TEST");
 
-    screen.toggle_tab(1);
+    screen.toggle_tab(1).expect("TEST");
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
         0,
         "Active tab toggler to previous tab"
     );
 
-    screen.toggle_tab(1);
+    screen.toggle_tab(1).expect("TEST");
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
         1,
@@ -309,7 +311,7 @@ pub fn toggle_to_previous_tab_create_tabs_only() {
         "Tab history is invalid"
     );
 
-    screen.toggle_tab(1);
+    screen.toggle_tab(1).expect("TEST");
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
         1,
@@ -321,7 +323,7 @@ pub fn toggle_to_previous_tab_create_tabs_only() {
         "Tab history is invalid"
     );
 
-    screen.toggle_tab(1);
+    screen.toggle_tab(1).expect("TEST");
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
         2,
@@ -333,7 +335,7 @@ pub fn toggle_to_previous_tab_create_tabs_only() {
         "Tab history is invalid"
     );
 
-    screen.toggle_tab(1);
+    screen.toggle_tab(1).expect("TEST");
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
         1,
@@ -365,7 +367,7 @@ pub fn toggle_to_previous_tab_delete() {
         "Active tab toggler to previous tab"
     );
 
-    screen.toggle_tab(1);
+    screen.toggle_tab(1).expect("TEST");
     assert_eq!(
         screen.tab_history.get(&1).unwrap(),
         &[0, 1, 3],
@@ -377,7 +379,7 @@ pub fn toggle_to_previous_tab_delete() {
         "Active tab toggler to previous tab"
     );
 
-    screen.toggle_tab(1);
+    screen.toggle_tab(1).expect("TEST");
     assert_eq!(
         screen.tab_history.get(&1).unwrap(),
         &[0, 1, 2],
@@ -389,7 +391,7 @@ pub fn toggle_to_previous_tab_delete() {
         "Active tab toggler to previous tab"
     );
 
-    screen.switch_tab_prev(1);
+    screen.switch_tab_prev(1).expect("TEST");
     assert_eq!(
         screen.tab_history.get(&1).unwrap(),
         &[0, 1, 3],
@@ -400,7 +402,7 @@ pub fn toggle_to_previous_tab_delete() {
         2,
         "Active tab toggler to previous tab"
     );
-    screen.switch_tab_prev(1);
+    screen.switch_tab_prev(1).expect("TEST");
     assert_eq!(
         screen.tab_history.get(&1).unwrap(),
         &[0, 3, 2],
@@ -412,7 +414,7 @@ pub fn toggle_to_previous_tab_delete() {
         "Active tab toggler to previous tab"
     );
 
-    screen.close_tab(1);
+    screen.close_tab(1).expect("TEST");
     assert_eq!(
         screen.tab_history.get(&1).unwrap(),
         &[0, 3],
@@ -424,7 +426,7 @@ pub fn toggle_to_previous_tab_delete() {
         "Active tab toggler to previous tab"
     );
 
-    screen.toggle_tab(1);
+    screen.toggle_tab(1).expect("TEST");
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
         2,
@@ -453,7 +455,7 @@ fn switch_to_tab_with_fullscreen() {
     }
     new_tab(&mut screen, 2);
 
-    screen.switch_tab_prev(1);
+    screen.switch_tab_prev(1).expect("TEST");
 
     assert_eq!(
         screen.get_active_tab(1).unwrap().position,
@@ -566,7 +568,7 @@ fn attach_after_first_tab_closed() {
     }
     new_tab(&mut screen, 2);
 
-    screen.close_tab_at_index(0);
-    screen.remove_client(1);
-    screen.add_client(1);
+    screen.close_tab_at_index(0).expect("TEST");
+    screen.remove_client(1).expect("TEST");
+    screen.add_client(1).expect("TEST");
 }