errors: handle missing plugin caches

CHANGELOG.md

@@ -16,6 +16,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 * fix: disallow path-like names for sessions (https://github.com/zellij-org/zellij/pull/2082)
 * errors: Remove more `unwrwap`s from server code (https://github.com/zellij-org/zellij/pull/2069)
 * fix: support UTF-8 character in tab name and pane name (https://github.com/zellij-org/zellij/pull/2102)
+* fix: handle missing/inaccessible cache directory (https://github.com/zellij-org/zellij/pull/2093)
 
 ## [0.34.4] - 2022-12-13
 

zellij-server/src/plugins/wasm_bridge.rs

@@ -247,6 +247,15 @@ impl WasmBridge {
  let plugin_own_data_dir = ZELLIJ_CACHE_DIR.join(Url::from(&plugin.location).to_string());
  let cache_hit = self.plugin_cache.contains_key(&plugin.path);
 
+ // Create filesystem entries mounted into WASM.
+ // We create them here to get expressive error messages in case they fail.
+ fs::create_dir_all(&plugin_own_data_dir)
+ .with_context(|| format!("failed to create datadir in {plugin_own_data_dir:?}"))
+ .with_context(err_context)?;
+ fs::create_dir_all(ZELLIJ_TMP_DIR.as_path())
+ .with_context(|| format!("failed to create tmpdir at {:?}", &ZELLIJ_TMP_DIR.as_path()))
+ .with_context(err_context)?;
+
  // We remove the entry here and repopulate it at the very bottom, if everything went well.
  // We must do that because a `get` will only give us a borrow of the Module. This suffices for
  // the purpose of setting everything up, but we cannot return a &Module from the "None" match
@@ -277,19 +286,6 @@ impl WasmBridge {
  .with_context(err_context)
  .fatal();
 
- fs::create_dir_all(&plugin_own_data_dir)
- .with_context(|| format!("failed to create datadir in {plugin_own_data_dir:?}"))
- .with_context(err_context)
- .non_fatal();
-
- // ensure tmp dir exists, in case it somehow was deleted (e.g systemd-tmpfiles)
- fs::create_dir_all(ZELLIJ_TMP_DIR.as_path())
- .with_context(|| {
- format!("failed to create tmpdir at {:?}", &ZELLIJ_TMP_DIR.as_path())
- })
- .with_context(err_context)
- .non_fatal();
-
  let hash: String = PortableHash::default()
  .hash256(&wasm_bytes)
  .iter()
@@ -310,16 +306,17 @@ impl WasmBridge {
  Err(e) => {
  let inner_context = || format!("failed to recover from {e:?}");
 
- let m = Module::new(&self.store, &wasm_bytes)
- .with_context(inner_context)
- .with_context(err_context)?;
  fs::create_dir_all(ZELLIJ_CACHE_DIR.to_owned())
+ .map_err(anyError::new)
+ .and_then(|_| {
+ Module::new(&self.store, &wasm_bytes).map_err(anyError::new)
+ })
+ .and_then(|m| {
+ m.serialize_to_file(&cached_path).map_err(anyError::new)?;
+ Ok(m)
+ })
  .with_context(inner_context)
- .with_context(err_context)?;
- m.serialize_to_file(&cached_path)
- .with_context(inner_context)
- .with_context(err_context)?;
- m
+ .with_context(err_context)?
  },
  }
  }

zellij-utils/src/errors.rs

@@ -16,9 +16,6 @@ use serde::{Deserialize, Serialize};
 use std::fmt::{Display, Error, Formatter};
 use std::path::PathBuf;
 
-use miette::Diagnostic;
-use thiserror::Error as ThisError;
-
 /// Re-exports of common error-handling code.
 pub mod prelude {
  pub use super::FatalError;
@@ -37,39 +34,6 @@ pub trait ErrorInstruction {
  fn error(err: String) -> Self;
 }
 
-#[derive(Debug, ThisError, Diagnostic)]
-#[error("{0}{}", self.show_backtrace())]
-#[diagnostic(help("{}", self.show_help()))]
-struct Panic(String);
-
-impl Panic {
- // We already capture a backtrace with `anyhow` using the `backtrace` crate in the background.
- // The advantage is that this is the backtrace of the real errors source (i.e. where we first
- // encountered the error and turned it into an `anyhow::Error`), whereas the backtrace recorded
- // here is the backtrace leading to the call to any `panic`ing function. Since now we propagate
- // errors up before `unwrap`ing them (e.g. in `zellij_server::screen::screen_thread_main`), the
- // former is what we really want to diagnose.
- // We still keep the second one around just in case the first backtrace isn't meaningful or
- // non-existent in the first place (Which really shouldn't happen, but you never know).
- fn show_backtrace(&self) -> String {
- if let Ok(var) = std::env::var("RUST_BACKTRACE") {
- if !var.is_empty() && var != "0" {
- return format!("\n\nPanic backtrace:\n{:?}", backtrace::Backtrace::new());
- }
- }
- "".into()
- }
-
- fn show_help(&self) -> String {
- r#"If you are seeing this message, it means that something went wrong.
-Please report this error to the github issue.
-(https://github.com/zellij-org/zellij/issues)
-
-Also, if you want to see the backtrace, you can set the `RUST_BACKTRACE` environment variable to `1`.
-"#.into()
- }
-}
-
 /// Helper trait to easily log error types.
 ///
 /// The `print_error` function takes a closure which takes a `&str` and fares with it as necessary
@@ -514,13 +478,51 @@ pub use not_wasm::*;
 mod not_wasm {
  use super::*;
  use crate::channels::{SenderWithContext, ASYNCOPENCALLS, OPENCALLS};
- use miette::{GraphicalReportHandler, GraphicalTheme, Report};
+ use miette::{Diagnostic, GraphicalReportHandler, GraphicalTheme, Report};
  use std::panic::PanicInfo;
+ use thiserror::Error as ThisError;
 
  /// The maximum amount of calls an [`ErrorContext`] will keep track
  /// of in its stack representation. This is a per-thread maximum.
  const MAX_THREAD_CALL_STACK: usize = 6;
 
+ #[derive(Debug, ThisError, Diagnostic)]
+ #[error("{0}{}", self.show_backtrace())]
+ #[diagnostic(help("{}", self.show_help()))]
+ struct Panic(String);
+
+ impl Panic {
+ // We already capture a backtrace with `anyhow` using the `backtrace` crate in the background.
+ // The advantage is that this is the backtrace of the real errors source (i.e. where we first
+ // encountered the error and turned it into an `anyhow::Error`), whereas the backtrace recorded
+ // here is the backtrace leading to the call to any `panic`ing function. Since now we propagate
+ // errors up before `unwrap`ing them (e.g. in `zellij_server::screen::screen_thread_main`), the
+ // former is what we really want to diagnose.
+ // We still keep the second one around just in case the first backtrace isn't meaningful or
+ // non-existent in the first place (Which really shouldn't happen, but you never know).
+ fn show_backtrace(&self) -> String {
+ if let Ok(var) = std::env::var("RUST_BACKTRACE") {
+ if !var.is_empty() && var != "0" {
+ return format!("\n\nPanic backtrace:\n{:?}", backtrace::Backtrace::new());
+ }
+ }
+ "".into()
+ }
+
+ fn show_help(&self) -> String {
+ format!(
+ "If you are seeing this message, it means that something went wrong.
+
+-> To get additional information, check the log at: {}
+-> To see a backtrace next time, reproduce the error with: RUST_BACKTRACE=1 zellij [...]
+-> To help us fix this, please open an issue: https://github.com/zellij-org/zellij/issues
+
+",
+ crate::consts::ZELLIJ_TMP_LOG_FILE.display().to_string()
+ )
+ }
+ }
+
  /// Custom panic handler/hook. Prints the [`ErrorContext`].
  pub fn handle_panic<T>(info: &PanicInfo<'_>, sender: &SenderWithContext<T>)
  where