diff --git a/BioArchLinux/r-pak/lilac.py b/BioArchLinux/r-pak/lilac.py
index abea90b0f9..e9e36ffb3f 100644
--- a/BioArchLinux/r-pak/lilac.py
+++ b/BioArchLinux/r-pak/lilac.py
@@ -6,26 +6,22 @@ import sys
 sys.path.append(os.path.normpath(f'{__file__}/../../../lilac-extensions'))
 from lilac_r_utils import r_pre_build
 
-import tarfile
+def get_depends(tar):
+    # Get the names of dependencies in embedded library
+    prefix = "pak/src/library/"
+    for member in tar.getmembers():
+        name = member.name
+        if not name.startswith(prefix) or not member.isdir():
+            continue
+        name = name[len(prefix):]
+        if "/" not in name:
+            yield name
 
 def pre_build():
-    # Get the names of dependencies in embedded library
-    deps = []
-    newver = _G.newver.rsplit("#", 1)[0]
-    with tarfile.open(f"pak_{newver}.tar.gz", "r:gz") as tar:
-        prefix = "pak/src/library/"
-        for member in tar.getmembers():
-            name = member.name
-            if not name.startswith(prefix) or not member.isdir():
-                continue
-            name = name[len(prefix):]
-            if "/" not in name:
-                deps.append(name)
-
     r_pre_build(
         _G,
         expect_needscompilation = True,
-        extra_r_depends = deps,
+        extra_r_depends_cb = get_depends,
     )
 
 def post_build():
diff --git a/lilac-extensions/lilac_r_utils.py b/lilac-extensions/lilac_r_utils.py
index 5a514f6d0b..133a1d4c69 100644
--- a/lilac-extensions/lilac_r_utils.py
+++ b/lilac-extensions/lilac_r_utils.py
@@ -236,14 +236,14 @@ class CheckConfig:
         expect_needscompilation: bool = None,
         expect_systemrequirements: str = None,
         expect_title: str = None,
-        extra_r_depends: list = [],
+        extra_r_depends_cb = None,
         ignore_fortran_files: bool = False,
     ):
         self.expect_license = expect_license
         self.expect_needscompilation = expect_needscompilation
         self.expect_systemrequirements = expect_systemrequirements
         self.expect_title = expect_title
-        self.extra_r_depends = extra_r_depends
+        self.extra_r_depends_cb = extra_r_depends_cb
         self.ignore_fortran_files = ignore_fortran_files
 
 def check_default_pkgs(pkg: Pkgbuild, desc: Description, cfg: CheckConfig):
@@ -258,7 +258,9 @@ def check_default_pkgs(pkg: Pkgbuild, desc: Description, cfg: CheckConfig):
 def check_depends(pkg: Pkgbuild, desc: Description, cfg: CheckConfig):
     implicit_r_dep = explicit_r_dep = False
     expected_depends = set(desc.depends + desc.imports)
-    expected_depends.update((_r_name_to_arch(dep) for dep in cfg.extra_r_depends))
+    cb = cfg.extra_r_depends_cb
+    if cb is not None:
+        expected_depends.update((_r_name_to_arch(dep) for dep in cb(cfg.tar)))
     errors = []
     for dep in pkg.depends:
         if dep.startswith("r-"):