Add EvalErrorBuilder::panic()

An nicer alternative to printError + abort, or assert(false /* foo */)

src/libexpr/eval-error.cc

@@ -92,6 +92,14 @@ void EvalErrorBuilder<T>::debugThrow()
  throw error;
 }
 
+template<class T>
+void EvalErrorBuilder<T>::panic()
+{
+ logError(error.info());
+ printError("This is a bug! An unexpected condition occurred, causing the Nix evaluator to have to stop. If you could share a reproducible example or a core dump, please open an issue at https://github.com/NixOS/nix/issues");
+ abort();
+}
+
 template class EvalErrorBuilder<EvalBaseError>;
 template class EvalErrorBuilder<EvalError>;
 template class EvalErrorBuilder<AssertionError>;

src/libexpr/eval-error.hh

@@ -112,6 +112,12 @@ public:
  * Delete the `EvalErrorBuilder` and throw the underlying exception.
  */
  [[gnu::noinline, gnu::noreturn]] void debugThrow();
+
+ /**
+ * A programming error or fatal condition occurred. Abort the process for core dump and debugging.
+ * This does not print a proper backtrace, because unwinding the stack is destructive.
+ */
+ [[gnu::noinline, gnu::noreturn]] void panic();
 };
 
 }