From bbeddf06027424dc08742c1d54bf2fdc85ff6e8e Mon Sep 17 00:00:00 2001
From: Tom Bereknyei <tomberek@gmail.com>
Date: Fri, 12 May 2023 07:44:25 -0400
Subject: [PATCH] fix: refactor parseCmdline interface

---
 src/libutil/args.cc | 9 ++++-----
 src/libutil/args.hh | 2 +-
 src/nix/main.cc     | 5 ++++-
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/libutil/args.cc b/src/libutil/args.cc
index d90374adc..481ed33ff 100644
--- a/src/libutil/args.cc
+++ b/src/libutil/args.cc
@@ -83,10 +83,10 @@ std::optional<std::string> RootArgs::needsCompletion(std::string_view s)
 void RootArgs::parseCmdline(const Strings & _cmdline)
 {
     // Default via 5.1.2.2.1 in C standard
-    Args::parseCmdline("", _cmdline);
+    Args::parseCmdline(_cmdline, false);
 }
 
-void Args::parseCmdline(const std::string & programName, const Strings & _cmdline)
+void Args::parseCmdline(const Strings & _cmdline, bool allowShebang)
 {
     Strings pendingArgs;
     bool dashDash = false;
@@ -107,8 +107,7 @@ void Args::parseCmdline(const std::string & programName, const Strings & _cmdlin
     // if we have at least one argument, it's the name of an
     // executable file, and it starts with "#!".
     Strings savedArgs;
-    auto isNixCommand = std::regex_search(programName, std::regex("nix$"));
-    if (isNixCommand && cmdline.size() > 0) {
+    if (allowShebang){
         auto script = *cmdline.begin();
         try {
             std::ifstream stream(script);
@@ -121,7 +120,7 @@ void Args::parseCmdline(const std::string & programName, const Strings & _cmdlin
 
                 std::string line;
                 std::getline(stream,line);
-                std::string commentChars("#/\\%@*-");
+                static const std::string commentChars("#/\\%@*-");
                 while (std::getline(stream,line) && !line.empty() && commentChars.find(line[0]) != std::string::npos){
                     line = chomp(line);
 
diff --git a/src/libutil/args.hh b/src/libutil/args.hh
index 1d056678d..e753dcaf6 100644
--- a/src/libutil/args.hh
+++ b/src/libutil/args.hh
@@ -30,7 +30,7 @@ public:
      * Parse the command line with argv0, throwing a UsageError if something
        goes wrong.
      */
-    void parseCmdline(const std::string & argv0, const Strings & cmdline);
+    void parseCmdline(const Strings & _cmdline, bool allowShebang);
 
     /**
      * Return a short one-line description of the command.
diff --git a/src/nix/main.cc b/src/nix/main.cc
index 16fb50806..73641f6d2 100644
--- a/src/nix/main.cc
+++ b/src/nix/main.cc
@@ -22,6 +22,7 @@
 #include <ifaddrs.h>
 #include <netdb.h>
 #include <netinet/in.h>
+#include <regex>
 
 #include <nlohmann/json.hpp>
 
@@ -428,7 +429,9 @@ void mainWrapped(int argc, char * * argv)
     });
 
     try {
-        args.parseCmdline(programName, argvToStrings(argc, argv));
+        auto isNixCommand = std::regex_search(programName, std::regex("nix$"));
+        auto allowShebang = isNixCommand && argc > 1;
+        args.parseCmdline(argvToStrings(argc, argv),allowShebang);
     } catch (UsageError &) {
         if (!args.helpRequested && !args.completions) throw;
     }