[Bugfix] Fix triton import with local TritonPlaceholder (#17446)

Signed-off-by: Mengqing Cao <cmq0113@163.com>

tests/test_triton_utils.py

@@ -0,0 +1,92 @@
+# SPDX-License-Identifier: Apache-2.0
+
+import sys
+import types
+from unittest import mock
+
+from vllm.triton_utils.importing import (TritonLanguagePlaceholder,
+                                         TritonPlaceholder)
+
+
+def test_triton_placeholder_is_module():
+    triton = TritonPlaceholder()
+    assert isinstance(triton, types.ModuleType)
+    assert triton.__name__ == "triton"
+
+
+def test_triton_language_placeholder_is_module():
+    triton_language = TritonLanguagePlaceholder()
+    assert isinstance(triton_language, types.ModuleType)
+    assert triton_language.__name__ == "triton.language"
+
+
+def test_triton_placeholder_decorators():
+    triton = TritonPlaceholder()
+
+    @triton.jit
+    def foo(x):
+        return x
+
+    @triton.autotune
+    def bar(x):
+        return x
+
+    @triton.heuristics
+    def baz(x):
+        return x
+
+    assert foo(1) == 1
+    assert bar(2) == 2
+    assert baz(3) == 3
+
+
+def test_triton_placeholder_decorators_with_args():
+    triton = TritonPlaceholder()
+
+    @triton.jit(debug=True)
+    def foo(x):
+        return x
+
+    @triton.autotune(configs=[], key="x")
+    def bar(x):
+        return x
+
+    @triton.heuristics(
+        {"BLOCK_SIZE": lambda args: 128 if args["x"] > 1024 else 64})
+    def baz(x):
+        return x
+
+    assert foo(1) == 1
+    assert bar(2) == 2
+    assert baz(3) == 3
+
+
+def test_triton_placeholder_language():
+    lang = TritonLanguagePlaceholder()
+    assert isinstance(lang, types.ModuleType)
+    assert lang.__name__ == "triton.language"
+    assert lang.constexpr is None
+    assert lang.dtype is None
+    assert lang.int64 is None
+
+
+def test_triton_placeholder_language_from_parent():
+    triton = TritonPlaceholder()
+    lang = triton.language
+    assert isinstance(lang, TritonLanguagePlaceholder)
+
+
+def test_no_triton_fallback():
+    # clear existing triton modules
+    sys.modules.pop("triton", None)
+    sys.modules.pop("triton.language", None)
+    sys.modules.pop("vllm.triton_utils", None)
+    sys.modules.pop("vllm.triton_utils.importing", None)
+
+    # mock triton not being installed
+    with mock.patch.dict(sys.modules, {"triton": None}):
+        from vllm.triton_utils import HAS_TRITON, tl, triton
+        assert HAS_TRITON is False
+        assert triton.__class__.__name__ == "TritonPlaceholder"
+        assert triton.language.__class__.__name__ == "TritonLanguagePlaceholder"
+        assert tl.__class__.__name__ == "TritonLanguagePlaceholder"