diff --git a/src/libexpr/parser-state.hh b/src/libexpr/parser-state.hh index 5a7bcb717..4bb5c9204 100644 --- a/src/libexpr/parser-state.hh +++ b/src/libexpr/parser-state.hh @@ -291,12 +291,23 @@ inline Expr * ParserState::stripIndentation(const PosIdx pos, s2 = std::string(s2, 0, p + 1); } - es2->emplace_back(i->first, new ExprString(std::move(s2))); + // Ignore empty strings for a minor optimisation and AST simplification + if (s2 != "") { + es2->emplace_back(i->first, new ExprString(std::move(s2))); + } }; for (; i != es.end(); ++i, --n) { std::visit(overloaded { trimExpr, trimString }, i->second); } + // If there is nothing at all, return the empty string directly. + // This also ensures that equivalent empty strings result in the same ast, which is helpful when testing formatters. + if (es2->size() == 0) { + auto *const result = new ExprString(""); + delete es2; + return result; + } + /* If this is a single string, then don't do a concatenation. */ if (es2->size() == 1 && dynamic_cast((*es2)[0].second)) { auto *const result = (*es2)[0].second; diff --git a/tests/functional/lang/parse-okay-ind-string.exp b/tests/functional/lang/parse-okay-ind-string.exp new file mode 100644 index 000000000..82e9940a2 --- /dev/null +++ b/tests/functional/lang/parse-okay-ind-string.exp @@ -0,0 +1 @@ +(let string = "str"; in [ (/some/path) ((/some/path)) ((/some/path)) ((/some/path + "\n end")) (string) ((string)) ((string)) ((string + "\n end")) ("") ("") ("end") ]) diff --git a/tests/functional/lang/parse-okay-ind-string.nix b/tests/functional/lang/parse-okay-ind-string.nix new file mode 100644 index 000000000..97c9de3cd --- /dev/null +++ b/tests/functional/lang/parse-okay-ind-string.nix @@ -0,0 +1,31 @@ +let + string = "str"; +in [ + /some/path + + ''${/some/path}'' + + '' + ${/some/path}'' + + ''${/some/path} + end'' + + string + + ''${string}'' + + '' + ${string}'' + + ''${string} + end'' + + '''' + + '' + '' + + '' + end'' +]