From 45c3c2ea8ec5a06b2c7ede465f85f90ac0c41a05 Mon Sep 17 00:00:00 2001
From: Henry Schreiner <HenrySchreinerIII@gmail.com>
Date: Sun, 17 Jan 2021 13:08:55 -0500
Subject: [PATCH] fix: empty image check (#543)

---
 cibuildwheel/docker_container.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/cibuildwheel/docker_container.py b/cibuildwheel/docker_container.py
index aee933d2..e18eed8c 100644
--- a/cibuildwheel/docker_container.py
+++ b/cibuildwheel/docker_container.py
@@ -30,6 +30,9 @@ class DockerContainer:
     bash_stdout: IO[bytes]
 
     def __init__(self, docker_image: str, simulate_32_bit: bool = False, cwd: Optional[PathOrStr] = None):
+        if not docker_image:
+            raise ValueError("Must have a non-empty docker image to run.")
+
         self.docker_image = docker_image
         self.simulate_32_bit = simulate_32_bit
         self.cwd = cwd