From 032eff7f6919daf8c4065ccdba776f23f1701174 Mon Sep 17 00:00:00 2001
From: eldritch horrors <pennae@lix.systems>
Date: Mon, 4 Mar 2024 05:06:32 +0100
Subject: Merge pull request #8470 from ncfavier/shebang-single-quotes

nix-shell: support single quotes in shebangs, fix whitespace parsing
(cherry picked from commit 3b99c6291377cbd22607896af9dfafa857d2f2dc)
Change-Id: I2a431b21c3467eefa1ef95d5a36d672f45b6937a
---
 src/nix-build/nix-build.cc | 38 ++++++++++++++++++++++++++------------
 1 file changed, 26 insertions(+), 12 deletions(-)

(limited to 'src')

diff --git a/src/nix-build/nix-build.cc b/src/nix-build/nix-build.cc
index 2895c5e3c..e62c4f6b1 100644
--- a/src/nix-build/nix-build.cc
+++ b/src/nix-build/nix-build.cc
@@ -34,13 +34,14 @@ extern char * * environ __attribute__((weak));
  */
 static std::vector<std::string> shellwords(const std::string & s)
 {
-    std::regex whitespace("^(\\s+).*");
+    std::regex whitespace("^\\s+");
     auto begin = s.cbegin();
     std::vector<std::string> res;
     std::string cur;
     enum state {
         sBegin,
-        sQuote
+        sSingleQuote,
+        sDoubleQuote
     };
     state st = sBegin;
     auto it = begin;
@@ -50,26 +51,39 @@ static std::vector<std::string> shellwords(const std::string & s)
             if (regex_search(it, s.cend(), match, whitespace)) {
                 cur.append(begin, it);
                 res.push_back(cur);
-                cur.clear();
-                it = match[1].second;
+                it = match[0].second;
+                if (it == s.cend()) return res;
                 begin = it;
+                cur.clear();
             }
         }
         switch (*it) {
+            case '\'':
+                if (st != sDoubleQuote) {
+                    cur.append(begin, it);
+                    begin = it + 1;
+                    st = st == sBegin ? sSingleQuote : sBegin;
+                }
+                break;
             case '"':
-                cur.append(begin, it);
-                begin = it + 1;
-                st = st == sBegin ? sQuote : sBegin;
+                if (st != sSingleQuote) {
+                    cur.append(begin, it);
+                    begin = it + 1;
+                    st = st == sBegin ? sDoubleQuote : sBegin;
+                }
                 break;
             case '\\':
-                /* perl shellwords mostly just treats the next char as part of the string with no special processing */
-                cur.append(begin, it);
-                begin = ++it;
+                if (st != sSingleQuote) {
+                    /* perl shellwords mostly just treats the next char as part of the string with no special processing */
+                    cur.append(begin, it);
+                    begin = ++it;
+                }
                 break;
         }
     }
+    if (st != sBegin) throw Error("unterminated quote in shebang line");
     cur.append(begin, it);
-    if (!cur.empty()) res.push_back(cur);
+    res.push_back(cur);
     return res;
 }
 
@@ -128,7 +142,7 @@ static void main_nix_build(int argc, char * * argv)
                 for (auto line : lines) {
                     line = chomp(line);
                     std::smatch match;
-                    if (std::regex_match(line, match, std::regex("^#!\\s*nix-shell (.*)$")))
+                    if (std::regex_match(line, match, std::regex("^#!\\s*nix-shell\\s+(.*)$")))
                         for (const auto & word : shellwords(match[1].str()))
                             args.push_back(word);
                 }
-- 
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