module: add --preserve-symlinks-main

Add `--preserve-symlinks-main` option which behaves like
`--preserve-symlinks` but for `require.main`.

PR-URL: https://github.com/nodejs/node/pull/19911
Reviewed-By: James M Snell <jasnell@gmail.com>

3 files changed, 22 insertions, 1 deletions

diff --git a/src/node.cc b/src/node.cc
index 6411eafb8c..141846f6a1 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -237,6 +237,11 @@ bool trace_warnings = false;
 // that is used by lib/module.js
 bool config_preserve_symlinks = false;
 
+// Set in node.cc by ParseArgs when --preserve-symlinks-main is used.
+// Used in node_config.cc to set a constant on process.binding('config')
+// that is used by lib/module.js
+bool config_preserve_symlinks_main = false;
+
 // Set in node.cc by ParseArgs when --experimental-modules is used.
 // Used in node_config.cc to set a constant on process.binding('config')
 // that is used by lib/module.js
@@ -3529,6 +3534,8 @@ static void PrintHelp() {
          "  --pending-deprecation      emit pending deprecation warnings\n"
 #if defined(NODE_HAVE_I18N_SUPPORT)
          "  --preserve-symlinks        preserve symbolic links when resolving\n"
+         "  --preserve-symlinks-main   preserve symbolic links when resolving\n"
+         "                             the main module\n"
 #endif
          "  --prof-process             process v8 profiler output generated\n"
          "                             using --prof\n"
@@ -3579,7 +3586,6 @@ static void PrintHelp() {
          "  -r, --require              module to preload (option can be "
          "repeated)\n"
          "  -v, --version              print Node.js version\n"
-
          "\n"
          "Environment variables:\n"
          "NODE_DEBUG                   ','-separated list of core modules\n"
@@ -3842,6 +3848,8 @@ static void ParseArgs(int* argc,
       Revert(cve);
     } else if (strcmp(arg, "--preserve-symlinks") == 0) {
       config_preserve_symlinks = true;
+    } else if (strcmp(arg, "--preserve-symlinks-main") == 0) {
+      config_preserve_symlinks_main = true;
     } else if (strcmp(arg, "--experimental-modules") == 0) {
       config_experimental_modules = true;
       new_v8_argv[new_v8_argc] = "--harmony-dynamic-import";
@@ -4286,6 +4294,12 @@ void Init(int* argc,
         SafeGetenv("NODE_PRESERVE_SYMLINKS", &text) && text[0] == '1';
   }
 
+  {
+    std::string text;
+    config_preserve_symlinks_main =
+        SafeGetenv("NODE_PRESERVE_SYMLINKS_MAIN", &text) && text[0] == '1';
+  }
+
   if (config_warning_file.empty())
     SafeGetenv("NODE_REDIRECT_WARNINGS", &config_warning_file);
 
diff --git a/src/node_config.cc b/src/node_config.cc
index e2b2662abd..603d55491a 100644
--- a/src/node_config.cc
+++ b/src/node_config.cc
@@ -72,6 +72,8 @@ static void Initialize(Local<Object> target,
 
   if (config_preserve_symlinks)
     READONLY_BOOLEAN_PROPERTY("preserveSymlinks");
+  if (config_preserve_symlinks_main)
+    READONLY_BOOLEAN_PROPERTY("preserveSymlinksMain");
 
   if (config_experimental_modules) {
     READONLY_BOOLEAN_PROPERTY("experimentalModules");
diff --git a/src/node_internals.h b/src/node_internals.h
index 8aa4631880..c10369c563 100644
--- a/src/node_internals.h
+++ b/src/node_internals.h
@@ -173,6 +173,11 @@ extern std::string openssl_config;
 // that is used by lib/module.js
 extern bool config_preserve_symlinks;
 
+// Set in node.cc by ParseArgs when --preserve-symlinks-main is used.
+// Used in node_config.cc to set a constant on process.binding('config')
+// that is used by lib/module.js
+extern bool config_preserve_symlinks_main;
+
 // Set in node.cc by ParseArgs when --experimental-modules is used.
 // Used in node_config.cc to set a constant on process.binding('config')
 // that is used by lib/module.js