Fixed falsey behavior of empty list, moved ENTRYPOINT directive into …

…optional str to avoid entrypoint reset behavior

Signed-off-by: pryce-turner <[email protected]>

flytekit/image_spec/default_builder.py

@@ -74,7 +74,7 @@
 ENV PATH="$$PATH:/usr/local/nvidia/bin:/usr/local/cuda/bin" \
     LD_LIBRARY_PATH="/usr/local/nvidia/lib64:$$LD_LIBRARY_PATH"
 
-ENTRYPOINT $ENTRYPOINT
+$ENTRYPOINT
 
 $COPY_COMMAND_RUNTIME
 RUN $RUN_COMMANDS
@@ -194,10 +194,10 @@ def create_docker_context(image_spec: ImageSpec, tmp_dir: Path):
     else:
         python_version = f"{sys.version_info.major}.{sys.version_info.minor}"
 
-    if image_spec.entrypoint:
-        entrypoint = json.dumps(image_spec.entrypoint)
-    else:
+    if image_spec.entrypoint is None:
         entrypoint = ""
+    else:
+        entrypoint = f"ENTRYPOINT {json.dumps(image_spec.entrypoint)}"
 
     if image_spec.commands:
         run_commands = " && ".join(image_spec.commands)

tests/flytekit/unit/core/image_spec/test_default_builder.py

@@ -81,6 +81,24 @@ def test_create_docker_context_with_git_subfolder(tmp_path):
     assert requirements_path.exists()
 
 
+def test_create_docker_context_with_null_entrypoint(tmp_path):
+    docker_context_path = tmp_path / "builder_root"
+    docker_context_path.mkdir()
+
+    image_spec = ImageSpec(
+        name="FLYTEKIT",
+        python_version="3.12",
+        entrypoint=[],
+    )
+
+    create_docker_context(image_spec, docker_context_path)
+
+    dockerfile_path = docker_context_path / "Dockerfile"
+    assert dockerfile_path.exists()
+    dockerfile_content = dockerfile_path.read_text()
+    assert "ENTRYPOINT []" in dockerfile_content
+
+
 def test_create_docker_context_cuda(tmp_path):
     docker_context_path = tmp_path / "builder_root"
     docker_context_path.mkdir()