From 6c67bd4c1442e1db7e2f74e9a92e71b173fe8a3e Mon Sep 17 00:00:00 2001
From: Christopher Milan <chrismilan@ucla.edu>
Date: Wed, 1 Apr 2026 14:12:55 -0700
Subject: [PATCH] better error message when invalid renderer is specified
 (#15573)

---
 test/null/test_device.py | 5 +++++
 tinygrad/device.py       | 1 +
 2 files changed, 6 insertions(+)

diff --git a/test/null/test_device.py b/test/null/test_device.py
index 7dc3aaf3c4..6c1ab4f12f 100644
--- a/test/null/test_device.py
+++ b/test/null/test_device.py
@@ -24,6 +24,11 @@ class TestDevice(unittest.TestCase):
     with self.assertRaises(ModuleNotFoundError):
       Device["TYPO"]
 
+  @unittest.skipIf(Device.DEFAULT != "CPU", "only run on CPU")
+  def test_nonexistent_renderer(self):
+    with self.assertRaisesRegex(AssertionError, "No renderer"):
+      with Context(DEV="CPU:TYPO"): Device[Device.DEFAULT].renderer
+
   def test_lowercase_canonicalizes(self):
     device = Device.DEFAULT
     with Context(DEV=device.lower()):
diff --git a/tinygrad/device.py b/tinygrad/device.py
index 8437ccc0af..7e72f63f20 100644
--- a/tinygrad/device.py
+++ b/tinygrad/device.py
@@ -287,6 +287,7 @@ class Compiled:
     assert (rn:=next((self._renderer_name(r) for r in self.renderers if getenv(f"{self.device}_{self._renderer_name(r)}")), None)) is None, \
       f"{self.device}_{rn}=1 is deprecated, use DEV={self.device}:{rn} or {self.device}_CC={rn} instead"
     renderers = [r for r in self.renderers if self._renderer_name(r) == rn] if (rn:=DEV.target(self.device).renderer) else self.renderers
+    assert renderers, f"No renderer for {self.device} " + (f"matches request {rn!r}" if rn else "is available")
     return select_first_inited(renderers, f"No renderer for {self.device} is available", self.cached_renderer)
 
   def synchronize(self):