From 08252967a8c2ab15f3fb8bdfb848f007d4032d50 Mon Sep 17 00:00:00 2001 From: eldritch horrors Date: Fri, 8 Mar 2024 07:09:48 +0100 Subject: 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() are transformed like this: state.error("'%s' is not a string", getAttrPathStr()) .debugThrow() The type annotation has moved from `ErrorBuilder::debugThrow` to `EvalState::error`. (cherry picked from commit c6a89c1a1659b31694c0fbcd21d78a6dd521c732) Change-Id: Iced91ba4e00ca9e801518071fb43798936cbd05a --- src/libutil/error.cc | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'src/libutil/error.cc') diff --git a/src/libutil/error.cc b/src/libutil/error.cc index 9fac82a02..649caed86 100644 --- a/src/libutil/error.cc +++ b/src/libutil/error.cc @@ -334,7 +334,7 @@ std::ostream & showErrorInfo(std::ostream & out, const ErrorInfo & einfo, bool s * try { * e->eval(*this, env, v); * if (v.type() != nAttrs) - * throwTypeError("expected a set but found %1%", v); + * error("expected a set but found %1%", v); * } catch (Error & e) { * e.addTrace(pos, errorCtx); * throw; @@ -348,7 +348,7 @@ std::ostream & showErrorInfo(std::ostream & out, const ErrorInfo & einfo, bool s * e->eval(*this, env, v); * try { * if (v.type() != nAttrs) - * throwTypeError("expected a set but found %1%", v); + * error("expected a set but found %1%", v); * } catch (Error & e) { * e.addTrace(pos, errorCtx); * throw; @@ -410,7 +410,7 @@ std::ostream & showErrorInfo(std::ostream & out, const ErrorInfo & einfo, bool s oss << einfo.msg << "\n"; - printPosMaybe(oss, "", einfo.errPos); + printPosMaybe(oss, "", einfo.pos); auto suggestions = einfo.suggestions.trim(); if (!suggestions.suggestions.empty()) { -- cgit v1.2.3