From 6fe292d721703094893801578c08d4f0bb33c235 Mon Sep 17 00:00:00 2001
From: Adrian Gierakowski <agierakowski@gmail.com>
Date: Fri, 24 Jul 2020 12:28:05 +0100
Subject: [PATCH] writers.makeScriptWriter: fail build if interpreter of
 interpreter is a script

---
 pkgs/build-support/writers/default.nix | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/pkgs/build-support/writers/default.nix b/pkgs/build-support/writers/default.nix
index 90d0e5c98be0e..6a53824eac655 100644
--- a/pkgs/build-support/writers/default.nix
+++ b/pkgs/build-support/writers/default.nix
@@ -27,11 +27,20 @@ rec {
       # arguments to the interpreter are allowed.
       if [[ -n "${toString pkgs.stdenvNoCC.isDarwin}" ]] && isScript $interpreter
       then
-        wrapperInterpreter=$(head -1 "$interpreter" | tail -c+3)
+        wrapperInterpreterLine=$(head -1 "$interpreter" | tail -c+3)
+        # Get first word from the line (note: xargs echo remove leading spaces)
+        wrapperInterpreter=$(echo "$wrapperInterpreterLine" | xargs echo | cut -d " " -f1)
+
+        if isScript $wrapperInterpreter
+        then
+          echo "error: passed interpreter ($interpreter) is a script which has another script ($wrapperInterpreter) as an interpreter, which is not supported."
+          exit 1
+        fi
+
         # This should work as long as wrapperInterpreter is a shell, which is
         # the case for programs wrapped with makeWrapper, like
         # python3.withPackages etc.
-        interpreterLine="$wrapperInterpreter $interpreter"
+        interpreterLine="$wrapperInterpreterLine $interpreter"
       else
         interpreterLine=$interpreter
       fi