From 009cf9cd23e5b9198cf8977cca7c823b6b95ad5b Mon Sep 17 00:00:00 2001
From: Will Dietz <w@wdtz.org>
Date: Sun, 25 Feb 2018 16:38:13 -0600
Subject: [PATCH] nix search: explicitly handle empty search string, fixes
 #1893

This is important since this is given as an example.
Other patterns containing "empty search string" will still
be handled differently on different platforms ("asdf|")
but that's less of an issue.
---
 src/nix/search.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/nix/search.cc b/src/nix/search.cc
index 1adde28cb..009dfae9c 100644
--- a/src/nix/search.cc
+++ b/src/nix/search.cc
@@ -78,6 +78,11 @@ struct CmdSearch : SourceExprCommand, MixJSON
     {
         settings.readOnlyMode = true;
 
+        // Empty search string should match all packages
+        // Use "^" here instead of ".*" due to differences in resulting highlighting
+        // (see #1893 -- libc++ claims empty search string is not in POSIX grammar)
+        if (re.empty()) re = "^";
+
         std::regex regex(re, std::regex::extended | std::regex::icase);
 
         auto state = getEvalState();