From c473da5eaa67f471d16d7bd55166172b8143eb14 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <kirill@cynkra.com>
Date: Thu, 6 Mar 2025 14:01:48 +0100
Subject: [PATCH] chore: R 4.0 compat

---
 src/rinterface_extra.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/rinterface_extra.c b/src/rinterface_extra.c
index 6bf1148422..222fbad26d 100644
--- a/src/rinterface_extra.c
+++ b/src/rinterface_extra.c
@@ -8657,6 +8657,7 @@ SEXP R_igraph_add_env(SEXP graph) {
     SET_CLASS(result, Rf_duplicate(GET_CLASS(graph)));
   }
 
+#if defined(R_VERSION) && R_VERSION >= R_Version(4, 1, 0)
   // Get the base namespace
   SEXP base_ns = PROTECT(R_FindNamespace(Rf_mkString("base"))); px++;
   // Get the emptyenv function
@@ -8665,6 +8666,9 @@ SEXP R_igraph_add_env(SEXP graph) {
   SEXP empty_env = PROTECT(Rf_eval(Rf_lang1(empty_env_fun), R_GlobalEnv)); px++;
   // Evaluate the call
   SEXP env = PROTECT(R_NewEnv(empty_env, 0, 0)); px++;
+#else
+  SEXP env = Rf_allocSExp(ENVSXP);
+#endif
 
   SET_VECTOR_ELT(result, igraph_t_idx_env, env);