[Misc] Replace is_encoder_decoder_inputs with split_enc_dec_inputs (#15620)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

vllm/inputs/parse.py

@@ -1,15 +1,13 @@
 # SPDX-License-Identifier: Apache-2.0
-
 from collections.abc import Sequence
-from typing import Literal, TypedDict, Union, cast, overload
+from typing import Literal, Optional, TypedDict, Union, cast, overload
 
 from typing_extensions import TypeIs
 
 from vllm.utils import is_list_of
 
-from .data import (EncoderDecoderInputs, ExplicitEncoderDecoderPrompt,
-                   ProcessorInputs, PromptType, SingletonPrompt, TextPrompt,
-                   TokensPrompt)
+from .data import (ExplicitEncoderDecoderPrompt, ProcessorInputs, PromptType,
+                   SingletonInputs, SingletonPrompt, TextPrompt, TokensPrompt)
 
 
 class ParsedText(TypedDict):
@@ -110,6 +108,14 @@ def is_explicit_encoder_decoder_prompt(
     return isinstance(prompt, dict) and "encoder_prompt" in prompt
 
 
-def is_encoder_decoder_inputs(
-        inputs: ProcessorInputs) -> TypeIs[EncoderDecoderInputs]:
-    return "encoder" in inputs and "decoder" in inputs
+def split_enc_dec_inputs(
+    inputs: ProcessorInputs,
+) -> tuple[Optional[SingletonInputs], SingletonInputs]:
+    if "encoder" in inputs and "decoder" in inputs:
+        # NOTE: This passes pyright but not mypy
+        return (
+            inputs["encoder"],  # type: ignore[typeddict-item]
+            inputs["decoder"],  # type: ignore[typeddict-item]
+        )
+
+    return None, inputs

vllm/inputs/registry.py

@@ -19,7 +19,7 @@ from vllm.utils import (ClassRegistry, get_allowed_kwarg_only_overrides,
                         resolve_mm_processor_kwargs)
 
 from .data import ProcessorInputs, SingletonInputs
-from .parse import is_encoder_decoder_inputs
+from .parse import split_enc_dec_inputs
 
 if TYPE_CHECKING:
     from vllm.config import ModelConfig
@@ -462,13 +462,11 @@ class InputRegistry:
             **mm_processor_kwargs,
         )
 
-        if is_encoder_decoder_inputs(processed_inputs):
-            self._ensure_mm_kwargs(processed_inputs["encoder"],
-                                   mm_processor_kwargs)
-            self._ensure_mm_kwargs(processed_inputs["decoder"],
-                                   mm_processor_kwargs)
-        else:
-            self._ensure_mm_kwargs(processed_inputs, mm_processor_kwargs)
+        encoder_inputs, decoder_inputs = split_enc_dec_inputs(processed_inputs)
+        if encoder_inputs is not None:
+            self._ensure_mm_kwargs(encoder_inputs, mm_processor_kwargs)
+        if decoder_inputs is not None:
+            self._ensure_mm_kwargs(decoder_inputs, mm_processor_kwargs)
 
         return processed_inputs