BM25Retriever: UnicodeError Handling and Encoding Flexibility Improvement

[Restodecoca]

This improvement introduces the parameterization of character encoding in the data persistence and loading methods of the BM25Retriever, providing greater flexibility in handling stored JSON files. The enhancement addresses previous challenges encountered when dealing with different character sets across various environments, such as working with files generated on systems with diverse regional settings.

Previously, the encoding was fixed to utf-8, which caused difficulties when processing data containing special characters not properly supported in certain contexts, such as documents in multiple languages or file transfers between different operating systems. By adding the encoding parameter, users can now specify the desired encoding when saving and loading data, ensuring compatibility with different requirements, including Windows and Linux environments.

This enhancement also contributes to better system maintainability by allowing quick adjustments without requiring direct modifications to the source code. Additionally, it helps prevent common encoding-related errors, such as UnicodeDecodeError or incompatibilities when sharing data with third parties.

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

Fixes # (issue)

New Package?

Did I fill in the tool.llamahub section in the pyproject.toml and provide a detailed README.md for my new integration or package?

• Yes
• No

Version Bump?

Did I bump the version in the pyproject.toml file of the package I am updating? (Except for the llama-index-core package)

• Yes
• No

Type of Change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Your pull-request will likely not be merged unless it is covered by some form of impactful unit testing.

• I added new unit tests to cover this change
• I believe this change is already covered by existing unit tests

Suggested Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added Google Colab support for the newly added notebooks.
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I ran make format; make lint to appease the lint gods

[logan-markewich]

You know, if you write the PR description instead of using chatgpt, its usually a lot shorter and to the point 😉

[Restodecoca]

You know, if you write the PR description instead of using chatgpt, its usually a lot shorter and to the point 😉

I'll keep this in mind, thank you for the advice