nix/tests/functional/lang/eval-fail-using-set-as-attr-name.err.exp

error:
       … while evaluating an attribute name
         at /pwd/lang/eval-fail-using-set-as-attr-name.nix:5:10:
            4| in
            5|   attr.${key}
             |          ^
            6|

       error: expected a string but found a set: { }
       at /pwd/lang/eval-fail-using-set-as-attr-name.nix:5:10:
            4| in
            5|   attr.${key}
             |          ^
            6|
Pass positions when evaluating This includes position information in more places, making debugging easier. Before: ``` $ nix-instantiate --show-trace --eval tests/functional/lang/eval-fail-using-set-as-attr-name.nix error: … while evaluating an attribute name at «none»:0: (source not available) error: value is a set while a string was expected ``` After: ``` error: … while evaluating an attribute name at /pwd/lang/eval-fail-using-set-as-attr-name.nix:5:10: 4\| in 5\| attr.${key} \| ^ 6\| error: value is a set while a string was expected ``` 2023-12-07 13:01:42 -05:00			`error:`
			`… while evaluating an attribute name`
			`at /pwd/lang/eval-fail-using-set-as-attr-name.nix:5:10:`
			`4\| in`
			`5\| attr.${key}`
			`\| ^`
			`6\|`

Print value on type error Adds the failing value to `value is <TYPE> while a <TYPE> is expected` error messages. 2023-12-06 19:03:01 -05:00			`error: expected a string but found a set: { }`
libexpr: Support structured error classes While preparing PRs like #9753, I've had to change error messages in dozens of code paths. It would be nice if instead of EvalError("expected 'boolean' but found '%1%'", showType(v)) we could write TypeError(v, "boolean") or similar. Then, changing the error message could be a mechanical refactor with the compiler pointing out places the constructor needs to be changed, rather than the error-prone process of grepping through the codebase. Structured errors would also help prevent the "same" error from having multiple slightly different messages, and could be a first step towards error codes / an error index. This PR reworks the exception infrastructure in `libexpr` to support exception types with different constructor signatures than `BaseError`. Actually refactoring the exceptions to use structured data will come in a future PR (this one is big enough already, as it has to touch every exception in `libexpr`). The core design is in `eval-error.hh`. Generally, errors like this: state.error("'%s' is not a string", getAttrPathStr()) .debugThrow<TypeError>() are transformed like this: state.error<TypeError>("'%s' is not a string", getAttrPathStr()) .debugThrow() The type annotation has moved from `ErrorBuilder::debugThrow` to `EvalState::error`. 2024-01-22 20:08:29 -05:00			`at /pwd/lang/eval-fail-using-set-as-attr-name.nix:5:10:`
			`4\| in`
			`5\| attr.${key}`
			`\| ^`
			`6\|`