From 393e9a5f3e3e4173579e204a642e9fe55ddaf461 Mon Sep 17 00:00:00 2001
From: Jean Boussier <jean.boussier@gmail.com>
Date: Wed, 18 Jun 2025 09:56:22 +0100
Subject: [PATCH] Optimize `rb_namespace_available`

Rather than to lazily check the env using a trinary
value, we can more straightforwardly check for the
env during the VM boot.

This allow `rb_namespace_available` to just be a pointer
dereference.
---
 eval.c               |  1 +
 internal/inits.h     |  3 +++
 internal/namespace.h |  9 ++++++++-
 namespace.c          | 30 ++++++++++--------------------
 4 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/eval.c b/eval.c
index c2fba6d984..74f31db5c0 100644
--- a/eval.c
+++ b/eval.c
@@ -78,6 +78,7 @@ ruby_setup(void)
 #endif
     Init_BareVM();
     rb_vm_encoded_insn_data_table_init();
+    Init_enable_namespace();
     Init_vm_objects();
     Init_fstring_table();
 
diff --git a/internal/inits.h b/internal/inits.h
index 03de289dd4..e618d87cc3 100644
--- a/internal/inits.h
+++ b/internal/inits.h
@@ -25,6 +25,9 @@ int Init_enc_set_filesystem_encoding(void);
 /* newline.c */
 void Init_newline(void);
 
+/* namespace.c */
+void Init_enable_namespace(void);
+
 /* vm.c */
 void Init_BareVM(void);
 void Init_vm_objects(void);
diff --git a/internal/namespace.h b/internal/namespace.h
index ad1507b50c..54ab129d6e 100644
--- a/internal/namespace.h
+++ b/internal/namespace.h
@@ -51,7 +51,14 @@ typedef struct rb_namespace_struct rb_namespace_t;
 #define NAMESPACE_CC(cc) (cc ? NAMESPACE_METHOD_ENTRY(cc->cme_) : NULL)
 #define NAMESPACE_CC_ENTRIES(ccs) (ccs ? NAMESPACE_METHOD_ENTRY(ccs->cme) : NULL)
 
-int rb_namespace_available(void);
+RUBY_EXTERN bool ruby_namespace_enabled;
+
+static inline bool
+rb_namespace_available(void)
+{
+    return ruby_namespace_enabled;
+}
+
 void rb_namespace_enable_builtin(void);
 void rb_namespace_disable_builtin(void);
 void rb_namespace_push_loading_namespace(const rb_namespace_t *);
diff --git a/namespace.c b/namespace.c
index af7fb4459c..42ffee08e3 100644
--- a/namespace.c
+++ b/namespace.c
@@ -47,29 +47,10 @@ static bool tmp_dir_has_dirsep;
 # define DIRSEP "/"
 #endif
 
-static int namespace_availability = 0;
+bool ruby_namespace_enabled = false; // extern
 
 VALUE rb_resolve_feature_path(VALUE klass, VALUE fname);
 static VALUE rb_namespace_inspect(VALUE obj);
-
-int
-rb_namespace_available(void)
-{
-    const char *env;
-    if (namespace_availability) {
-        return namespace_availability > 0 ? 1 : 0;
-    }
-    env = getenv("RUBY_NAMESPACE");
-    if (env && strlen(env) > 0) {
-        if (strcmp(env, "1") == 0) {
-            namespace_availability = 1;
-            return 1;
-        }
-    }
-    namespace_availability = -1;
-    return 0;
-}
-
 static void namespace_push(rb_thread_t *th, VALUE namespace);
 static VALUE namespace_pop(VALUE th_value);
 
@@ -1031,6 +1012,15 @@ namespace_define_loader_method(const char *name)
     rb_define_singleton_method(rb_mNamespaceLoader, name, rb_namespace_user_loading_func, -1);
 }
 
+void
+Init_enable_namespace(void)
+{
+    const char *env = getenv("RUBY_NAMESPACE");
+    if (env && strlen(env) == 1 && env[0] == '1') {
+        ruby_namespace_enabled = true;
+    }
+}
+
 void
 Init_Namespace(void)
 {