From e46090edb101acac20ab1e6260a0ba98c177206a Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Wed, 17 May 2017 11:58:01 +0200 Subject: [PATCH] builtins.match: Improve error message for bad regular expression Issue #1331. --- src/libexpr/primops.cc | 39 +++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 16 deletions(-) diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index 93b66269d..99ffddaeb 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -1709,26 +1709,33 @@ static void prim_hashString(EvalState & state, const Pos & pos, Value * * args, ‘null’ or a list containing substring matches. */ static void prim_match(EvalState & state, const Pos & pos, Value * * args, Value & v) { - std::regex regex(state.forceStringNoCtx(*args[0], pos), std::regex::extended); + auto re = state.forceStringNoCtx(*args[0], pos); - PathSet context; - const std::string str = state.forceString(*args[1], context, pos); + try { + std::regex regex(re, std::regex::extended); - std::smatch match; - if (!std::regex_match(str, match, regex)) { - mkNull(v); - return; - } + PathSet context; + const std::string str = state.forceString(*args[1], context, pos); - // the first match is the whole string - const size_t len = match.size() - 1; - state.mkList(v, len); - for (size_t i = 0; i < len; ++i) { - if (!match[i+1].matched) - mkNull(*(v.listElems()[i] = state.allocValue())); - else - mkString(*(v.listElems()[i] = state.allocValue()), match[i + 1].str().c_str()); + std::smatch match; + if (!std::regex_match(str, match, regex)) { + mkNull(v); + return; + } + + // the first match is the whole string + const size_t len = match.size() - 1; + state.mkList(v, len); + for (size_t i = 0; i < len; ++i) { + if (!match[i+1].matched) + mkNull(*(v.listElems()[i] = state.allocValue())); + else + mkString(*(v.listElems()[i] = state.allocValue()), match[i + 1].str().c_str()); + } + + } catch (std::regex_error &) { + throw EvalError("invalid regular expression ‘%s’, at %s", re, pos); } }