facebookincubator/velox

AI Summary: The issue describes a bug where `switch` blocks containing nested expressions evaluate differently based on whether a 'simplified' or 'non-simplified' execution path is taken. The simplified path incorrectly executes a specific condition and fails, while the non-simplified path does not. This discrepancy was discovered during testing for a `coalesce` rewrite pull request, indicating a potential issue in the expression evaluation or optimization logic.

AI Summary: The TPC-DS `toTableName` function is inefficient because it creates a full map of table names redundantly on each call and returns `std::string`, causing unnecessary string copies. The task is to optimize this by returning a `const &`, ensuring the inverted map is created only once, and potentially leveraging the `VELOX_DEFINE_ENUM_NAME` macro for enum-to-string conversion.

AI Summary: The task involves refactoring the Velox C++ library. Specifically, the `vectorToVariant` helper function, currently located in `fbcode/velox/vector/VariantToVector.h`, needs to be replaced with a new method, `valueAt(index)`, within the `BaseVector` class. This method should return a `Variant` object representing the value at the specified index.

AI Summary: This task requires migrating the Velox codebase from using custom functions `mapNameToTypeKind` and `mapTypeKindToName` to the new `TypeKindName::toTypeKind` and `TypeKindName::toName` methods, respectively. This involves finding all instances of the old functions and replacing them with the new ones, then removing the obsolete functions. The task references a related issue (#14094) for context.

AI Summary: The task involves refactoring the Velox C++ library to integrate the functionality of the `variantToVector` function into the existing `BaseVector::createConstant` API. This requires extending the latter's type support to match the former's broader range, effectively deprecating `variantToVector`. The goal is to improve code maintainability and reduce redundancy.

AI Summary: The task requires aligning the `Variant::hash()` function's output with that of `BaseVector::hashValueAt()`. This involves modifying the `Variant::hash()` function in the Velox C++ execution engine library to ensure consistent hashing behavior between scalar values and values within vectors, resolving discrepancies identified in related issues #14017 and #14018.