Description

This PR returns error values while checking pipeline input types and positional argument types. This should help return non-nested errors earlier and prevent confusing errors.

The positional argument change is directly related to an example given on Discord. Before this PR, this is the error shown:

Error: nu::shell::cant_convert

  × Can't convert to record.
    ╭─[/home/rose/tmp/script.nu:23:5]
 22 │         let entry = $in
 23 │ ╭─▶     {
 24 │ │         name: $entry,
 25 │ │         details: {
 26 │ │           context: $context
 27 │ │         }
 28 │ ├─▶     }
    · ╰──── can't convert error to record
 29 │       }
    ╰────

After this PR, this is the error shown:

Error: nu::shell::eval_block_with_input

  × Eval block failed with pipeline input
    ╭─[/home/rose/tmp/script.nu:23:5]
 22 │         let entry = $in
 23 │ ╭─▶     {
 24 │ │         name: $entry,
 25 │ │         details: {
 26 │ │           context: $context
 27 │ │         }
 28 │ ├─▶     }
    · ╰──── source value
 29 │       }
    ╰────

Error: nu::shell::type_mismatch

  × Type mismatch.
   ╭─[/home/rose/tmp/much.nu:3:38]
 2 │   $in | each { |elem|
 3 │     print $elem.details.context.yaml.0
   ·                                      ┬
   ·                                      ╰── Can't access record values with a row index. Try specifying a column name instead
 4 │   } | each { |elem|
   ╰────

I'm not certain if the pipeline input error check actually can ever be triggered, but it seems to be a good defensive error handling strategy regardless. My addition of the Value::Error case in the first place would suggest it can be, but after looking at it more closely the error that caused me to add the case in the first place was actually unrelated to input typechecking.

Additionally, this PR does not affect the handling of nested errors, so something like:

try { ... } catch {|e| $e | reject raw | to nuon }

works the same before and after this PR.

User-Facing Changes

Errors values detected as arguments to commands or as pipeline input to commands are immediately thrown, rather than passed to the command.

Tests + Formatting

• 🟢 toolkit fmt
• 🟢 toolkit clippy
• 🟢 toolkit test
• 🟢 toolkit test stdlib

After Submitting

N/A