errors: Don't unwrap in `server::os_input_output` (#1895)

* server/os_io: Redefine `ServerOsApi` result types

to use `anyhow::Result` instead. This mostly makes the need of custom
`SpawnTerminalError` obsolete (tbd in subsequent commits) and unifies
error handling across the application.

* utils/errors: Implement new `ZellijError` type

to replace any previously defined, isolated custom error types
throughout the application. Currently implements all error variants
found in `SpawnTerminalError`.

In the long term, this will allow zellij to fall back to a single error
type for all application-specific errors, instead of having different
error types per module.

* server/unit/screen: Impl new `ServerOsApi`

with updated `Result`-types.

* server/tab/unit: Impl new `ServerOsApi`

with updated `Result`-types.

* server/os_io: Impl new `ServerOsApi`

with updated `Result`-types.

* utils/ipc: Return `anyhow::Error` in `send`

rather than a `&'static str`, which isn't compatible with
`anyhow::Context`.

* server/tab: Handle `Result` in `resize_pty!`

which is returned due to the changed return types in `ServerOsApi`.

* server/tab: Handle new `Result`s

originating in the change to the `ServerOsApi` trait definition.

* server/screen: Handle new `Result`s

originating in the change to the `ServerOsApi` trait definition.

* server/panes/tiled: Handle new `Result`s

originating in the change to the `ServerOsApi` trait definition.

* server/panes/floating: Handle new `Result`s

originating in the change to the `ServerOsApi` trait definition.

* server/lib: Unwrap on new `Result`s

originating in the change to the `ServerOsApi` trait definition. The
functions here don't return a `Result` yet, this is better left to a
follow-up PR.

* server: Remove `SpawnTerminalError`

and make use of the new `ZellijError` instead. Make use of `anyhow`s
downcast capabilities to restore the underlying original errors where
necessary, as was done previously. This gives us the flexibility to
attach context information to all errors while still allowing us to
handle specific errors in greater detail.

* server/pty: Fix vars broken in rebase

* server/os_io: Remove last `SpawnTerminalError`

* changelog: Add PR #1895

1 files changed, 20 insertions, 0 deletions

diff --git a/zellij-utils/src/errors.rs b/zellij-utils/src/errors.rs
index 7ec02b9a5..1594912b6 100644
--- a/zellij-utils/src/errors.rs
+++ b/zellij-utils/src/errors.rs
@@ -24,6 +24,7 @@ pub mod prelude {
     pub use super::LoggableError;
     #[cfg(not(target_family = "wasm"))]
     pub use super::ToAnyhow;
+    pub use super::ZellijError;
     pub use anyhow::anyhow;
     pub use anyhow::bail;
     pub use anyhow::Context;
@@ -376,6 +377,25 @@ pub enum PtyWriteContext {
     Exit,
 }
 
+use thiserror::Error;
+#[derive(Debug, Error)]
+pub enum ZellijError {
+    #[error("could not find command '{command}' for terminal {terminal_id}")]
+    CommandNotFound { terminal_id: u32, command: String },
+
+    #[error("could not determine default editor")]
+    NoEditorFound,
+
+    #[error("failed to allocate another terminal id")]
+    NoMoreTerminalIds,
+
+    #[error("failed to start PTY")]
+    FailedToStartPty,
+
+    #[error("an error occured")]
+    GenericError { source: anyhow::Error },
+}
+
 #[cfg(not(target_family = "wasm"))]
 pub use not_wasm::*;