From e2d71bd1862cdda65f957c6a6c41016258d9e003 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Wed, 21 Feb 2018 15:34:40 +0100 Subject: [PATCH] Revert "libexpr: Fix prim_replaceStrings() to work on an empty source string" This reverts commit 4ea9707591beceacf9988b3c185faf50da238403. It causes an infinite loop in Nixpkgs evaluation, e.g. "nix-instantiate -A hello" hung. PR #1886. --- src/libexpr/primops.cc | 11 +++-------- tests/lang/eval-okay-replacestrings.exp | 2 +- tests/lang/eval-okay-replacestrings.nix | 2 -- 3 files changed, 4 insertions(+), 11 deletions(-) diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index ab9351f11..a800d2429 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -1913,26 +1913,21 @@ static void prim_replaceStrings(EvalState & state, const Pos & pos, Value * * ar auto s = state.forceString(*args[2], context, pos); string res; - // Loops one past last character to handle the case where 'from' contains an empty string. - for (size_t p = 0; p <= s.size(); ) { + for (size_t p = 0; p < s.size(); ) { bool found = false; auto i = from.begin(); auto j = to.begin(); for (; i != from.end(); ++i, ++j) if (s.compare(p, i->size(), *i) == 0) { found = true; + p += i->size(); res += j->first; - if (i->empty()) { - res += s[p++]; - } else { - p += i->size(); - } for (auto& path : j->second) context.insert(path); j->second.clear(); break; } - if (!found && p < s.size()) res += s[p++]; + if (!found) res += s[p++]; } mkString(v, res, context); diff --git a/tests/lang/eval-okay-replacestrings.exp b/tests/lang/eval-okay-replacestrings.exp index 590c281ac..a2add1b7b 100644 --- a/tests/lang/eval-okay-replacestrings.exp +++ b/tests/lang/eval-okay-replacestrings.exp @@ -1 +1 @@ -[ "faabar" "fbar" "fubar" "faboor" "fubar" "XaXbXcX" "X" ] +[ "faabar" "fbar" "fubar" "faboor" "fubar" ] diff --git a/tests/lang/eval-okay-replacestrings.nix b/tests/lang/eval-okay-replacestrings.nix index c84e9269f..6284a0e66 100644 --- a/tests/lang/eval-okay-replacestrings.nix +++ b/tests/lang/eval-okay-replacestrings.nix @@ -5,6 +5,4 @@ with builtins; (replaceStrings ["oo"] ["u"] "foobar") (replaceStrings ["oo" "a"] ["a" "oo"] "foobar") (replaceStrings ["oo" "oo"] ["u" "i"] "foobar") - (replaceStrings [""] ["X"] "abc") - (replaceStrings [""] ["X"] "") ]