Merge pull request NixOS#8470 from ncfavier/shebang-single-quotes

nix-shell: support single quotes in shebangs, fix whitespace parsing
(cherry picked from commit 3b99c62)
Change-Id: I2a431b21c3467eefa1ef95d5a36d672f45b6937a

doc/manual/src/command-ref/nix-shell.md

@@ -235,14 +235,14 @@ package like Terraform:
 
 ```bash
 #! /usr/bin/env nix-shell
-#! nix-shell -i bash --packages "terraform.withPlugins (plugins: [ plugins.openstack ])"
+#! nix-shell -i bash --packages 'terraform.withPlugins (plugins: [ plugins.openstack ])'
 
 terraform apply
 ```
 
 > **Note**
 >
-> You must use double quotes (`"`) when passing a simple Nix expression
+> You must use single or double quotes (`'`, `"`) when passing a simple Nix expression
 > in a nix-shell shebang.
 
 Finally, using the merging of multiple nix-shell shebangs the following
@@ -251,7 +251,7 @@ branch):
 
 ```haskell
 #! /usr/bin/env nix-shell
-#! nix-shell -i runghc --packages "haskellPackages.ghcWithPackages (ps: [ps.download-curl ps.tagsoup])"
+#! nix-shell -i runghc --packages 'haskellPackages.ghcWithPackages (ps: [ps.download-curl ps.tagsoup])'
 #! nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/nixos-20.03.tar.gz
 
 import Network.Curl.Download

doc/manual/src/release-notes/rl-next.md

@@ -1 +1,3 @@
 # Release X.Y (202?-??-??)
+
+- `nix-shell` shebang lines now support single-quoted arguments.

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);
                 }

tests/functional/nix-shell.sh

@@ -84,6 +84,11 @@ chmod a+rx $TEST_ROOT/spaced\ \\\'\"shell.shebang.rb
 output=$($TEST_ROOT/spaced\ \\\'\"shell.shebang.rb abc ruby)
 [ "$output" = '-e load(ARGV.shift) -- '"$TEST_ROOT"'/spaced \'\''"shell.shebang.rb abc ruby' ]
 
+# Test nix-shell shebang quoting
+sed -e "s|@ENV_PROG@|$(type -P env)|" shell.shebang.nix > $TEST_ROOT/shell.shebang.nix
+chmod a+rx $TEST_ROOT/shell.shebang.nix
+$TEST_ROOT/shell.shebang.nix
+
 # Test 'nix develop'.
 nix develop -f "$shellDotNix" shellDrv -c bash -c '[[ -n $stdenv ]]'
 

tests/functional/shell.shebang.nix

@@ -0,0 +1,10 @@
+#! @ENV_PROG@ nix-shell
+#! nix-shell -I nixpkgs=shell.nix --no-substitute
+#! nix-shell    --argstr s1 'foo "bar" \baz'"'"'qux'  --argstr s2 "foo 'bar' \"\baz" --argstr s3 \foo\ bar\'baz --argstr s4 ''  
+#! nix-shell shell.shebang.nix --command true
+{ s1, s2, s3, s4 }:
+assert s1 == ''foo "bar" \baz'qux'';
+assert s2 == "foo 'bar' \"baz";
+assert s3 == "foo bar'baz";
+assert s4 == "";
+(import <nixpkgs> {}).runCommand "nix-shell" {} ""