make better usage of error value in catch block (#8460)

# Description

Fixes: #8402  #8391

The cause of these issue if when we want to evaluate a expression with
`Value::Error`, nushell show error immediately. To fix the issue, we can
wrap the `Value::Error` into a `Value::Record`. So user can see the
message he want.

# User-Facing Changes

Before
```
❯ try { 1 / 0 } catch {|e| echo $"error is ($e)"}
Error: nu:🐚:division_by_zero

  × Division by zero.
   ╭─[entry #2:1:1]
 1 │ try { 1 / 0 } catch {|e| echo $"error is ($e)"}
   ·         ┬
   ·         ╰── division by zero
   ╰────
```

After
```
❯ try { 1 / 0 } catch {|e| echo $"error is ($e)"}
error is {msg: Division by zero., debug: DivisionByZero { span: Span { start: 43104, end: 43105 } }, raw: DivisionByZero { sp
an: Span { start: 43104, end: 43105 } }}
```

As we can see, error becomes a record with `msg`, `debug`, `raw`
columns.
1. msg column is a user friendly message.
2. debug column is more about `Value::Error` information as a string.
3. raw column is a `Value::Error` itself, if user want to re-raise the
error, just use `$e | get raw`

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

> **Note**
> from `nushell` you can also use the `toolkit` as follows
> ```bash
> use toolkit.nu # or use an `env_change` hook to activate it
automatically
> toolkit check pr
> ```

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
This commit is contained in:
WindSoilder
2023-03-16 11:56:18 +08:00
committed by GitHub
parent 21b84a6d65
commit 0b97f52a8b
2 changed files with 30 additions and 12 deletions

View File

@ -24,7 +24,7 @@ fn try_catch() {
fn catch_can_access_error() {
let output = nu!(
cwd: ".",
"try { foobarbaz } catch { |err| $err }"
"try { foobarbaz } catch { |err| $err | get raw }"
);
assert!(output.err.contains("External command failed"));
@ -34,7 +34,7 @@ fn catch_can_access_error() {
fn catch_can_access_error_as_dollar_in() {
let output = nu!(
cwd: ".",
"try { foobarbaz } catch { $in }"
"try { foobarbaz } catch { $in | get raw }"
);
assert!(output.err.contains("External command failed"));
@ -101,3 +101,12 @@ fn loop_try_break_on_command_should_show_successful() {
assert!(!output.out.contains("failed"));
}
#[test]
fn catch_block_can_use_error_object() {
let output = nu!(
cwd: ".",
"try {1 / 0} catch {|err| print ($err | get msg)}"
);
assert_eq!(output.out, "Division by zero.")
}