fix(sampling_params): validate token-id input types via a shared helper

[SuperMarioYL]

Summary

StopSequence, AllowedTokenIds, and InvalidTokenIds each duplicate the same logic — validate that a list of ints fits a fixed-size c_int array, then copy it in — and two of the three implement the validation incorrectly:

• AllowedTokenIds.initialize asserts isinstance(e, int) over self.ids, the zero-filled ctypes destination buffer (c_int * ALLOWED_TOKEN_IDS_MAX_LENGTH), instead of the caller-supplied ids. Every element of that buffer is already an int, so the guard can never fail. A non-int entry in allowed_token_ids therefore slips past the intended "all must be int" check and instead surfaces an opaque TypeError: 'str' object cannot be interpreted as an integer at the array assignment. It also iterates 256 elements regardless of the actual input size.
• InvalidTokenIds.initialize performs no element-type check at all.
• StopSequence.initialize already validates the input correctly — this is the reference behavior the other two should match.

Change

Extract a single helper, store_int_token_ids(dst, ids, max_length, name), that validates the input list (length + element type) with clear messages and copies it into the destination array, then route all three initializers through it.

• Fixes the dead/incorrect guard in AllowedTokenIds.
• Adds the missing element-type guard to InvalidTokenIds.
• Removes the duplicated logic and unifies the error messages.

Valid inputs round-trip identically (to_list() / to_string() unchanged); the only observable change is that invalid (non-int) input now fails fast with a clear AssertionError instead of an opaque ctypes TypeError.

Tests

Added unit_tests/server/core/objs/test_token_ids_validation.py covering, for all three structures, that valid ids are accepted and round-trip, that a non-int element is rejected, and that exceeding the capacity is rejected — plus direct tests of the helper. The non-int cases are red before this change (they raise TypeError, not AssertionError) and green after.

The new tests live in a separate file to avoid overlapping with the in-flight test changes in #1350.

[gemini-code-assist]

Code Review

This pull request introduces a helper function store_int_token_ids to centralize and deduplicate token ID validation and ctypes array copying, refactoring StopSequence, AllowedTokenIds, and InvalidTokenIds to use it. It also adds a comprehensive suite of unit tests. The review feedback suggests replacing assert statements with standard exceptions (ValueError and TypeError) to prevent validation from being bypassed when Python is run with optimization flags. Additionally, it recommends using type(e) is int instead of isinstance(e, int) to strictly reject boolean values, and updating the corresponding unit tests to reflect these changes.

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[gemini-code-assist]

Using assert statements for runtime validation of input arguments is discouraged because assertions can be globally disabled in Python when run with optimization flags (e.g., python -O). Instead, standard exceptions like ValueError and TypeError should be raised.

Additionally, isinstance(e, int) returns True for boolean values (e.g., True, False) because bool is a subclass of int in Python. To strictly validate that the token IDs are integers and not booleans, we should use type(e) is int.

Suggested change

	size = len(ids)
	assert size <= max_length, f"Too many {name}: {size} > {max_length}."
	assert all(isinstance(e, int) for e in ids), f"all {name} must be int."
	dst[:size] = ids[:]
	return size
	size = len(ids)
	if size > max_length:
	raise ValueError(f"Too many {name}: {size} > {max_length}.")
	if not all(type(e) is int for e in ids):
	raise TypeError(f"all {name} must be int.")
	dst[:size] = ids[:]
	return size

References

1. Do not use assert statements for runtime validation of arguments, as they can be compiled out when Python is run with optimization flags (-O).

[gemini-code-assist]

Update the test to expect TypeError instead of AssertionError following the validation improvement in store_int_token_ids. Also, add a boolean value (e.g., [1, True]) to the parameterized test cases to verify that booleans are correctly rejected.

Suggested change

	@pytest.mark.parametrize("bad_ids", [[1, 2, "3"], [1, 2.5], [None, 1]])
	def test_allowed_token_ids_rejects_non_int(bad_ids):
	# A non-int entry must fail with the explicit "all must be int" guard,
	# not slip past validation into an opaque ctypes TypeError.
	allowed_ids = AllowedTokenIds()
	with pytest.raises(AssertionError):
	allowed_ids.initialize(bad_ids)
	@pytest.mark.parametrize("bad_ids", [[1, 2, "3"], [1, 2.5], [None, 1], [1, True]])
	def test_allowed_token_ids_rejects_non_int(bad_ids):
	# A non-int entry must fail with the explicit "all must be int" guard,
	# not slip past validation into an opaque ctypes TypeError.
	allowed_ids = AllowedTokenIds()
	with pytest.raises(TypeError):
	allowed_ids.initialize(bad_ids)

[gemini-code-assist]

Update the test to expect ValueError instead of AssertionError for length overflow validation.

Suggested change

	def test_allowed_token_ids_rejects_too_many():
	allowed_ids = AllowedTokenIds()
	with pytest.raises(AssertionError):
	allowed_ids.initialize([1] * (ALLOWED_TOKEN_IDS_MAX_LENGTH + 1))
	def test_allowed_token_ids_rejects_too_many():
	allowed_ids = AllowedTokenIds()
	with pytest.raises(ValueError):
	allowed_ids.initialize([1] * (ALLOWED_TOKEN_IDS_MAX_LENGTH + 1))

[gemini-code-assist]

Update the test to expect TypeError instead of AssertionError and add a boolean test case (e.g., [4, False]).

Suggested change

	@pytest.mark.parametrize("bad_ids", [[4, "5"], [4, 5.0]])
	def test_invalid_token_ids_rejects_non_int(bad_ids):
	invalid_ids = InvalidTokenIds()
	with pytest.raises(AssertionError):
	invalid_ids.initialize(bad_ids)
	@pytest.mark.parametrize("bad_ids", [[4, "5"], [4, 5.0], [4, False]])
	def test_invalid_token_ids_rejects_non_int(bad_ids):
	invalid_ids = InvalidTokenIds()
	with pytest.raises(TypeError):
	invalid_ids.initialize(bad_ids)

[gemini-code-assist]

Update the test to expect ValueError instead of AssertionError.

Suggested change

	def test_invalid_token_ids_rejects_too_many():
	invalid_ids = InvalidTokenIds()
	with pytest.raises(AssertionError):
	invalid_ids.initialize([1] * (INVALID_TOKEN_IDS_MAX_LENGTH + 1))
	def test_invalid_token_ids_rejects_too_many():
	invalid_ids = InvalidTokenIds()
	with pytest.raises(ValueError):
	invalid_ids.initialize([1] * (INVALID_TOKEN_IDS_MAX_LENGTH + 1))

[gemini-code-assist]

Update the test to expect TypeError instead of AssertionError.

Suggested change

	def test_stop_sequence_rejects_non_int():
	seq = StopSequence()
	with pytest.raises(AssertionError):
	seq.initialize([1, "2"])
	def test_stop_sequence_rejects_non_int():
	seq = StopSequence()
	with pytest.raises(TypeError):
	seq.initialize([1, "2"])

[gemini-code-assist]

Update the test to expect ValueError instead of AssertionError.

Suggested change

	def test_store_int_token_ids_rejects_overflow():
	import ctypes
	buf = (ctypes.c_int * 2)()
	with pytest.raises(AssertionError):
	store_int_token_ids(buf, [1, 2, 3], 2, "test ids")
	def test_store_int_token_ids_rejects_overflow():
	import ctypes
	buf = (ctypes.c_int * 2)()
	with pytest.raises(ValueError):
	store_int_token_ids(buf, [1, 2, 3], 2, "test ids")