Pydantic v2 Migration, Weaviate v4 Upgrade, and UI Fixes

[fer-marino]

Description

This pull request implements a significant modernization of the codebase, primarily focusing on the migration to Pydantic v2 and upgrading the Weaviate client to v4.18.x. It also includes backward compatibility patches for existing benchmark results and addresses UI deprecation warnings.

Key Changes

1. Pydantic v2 Migration

• Updated configuration models to comply with Pydantic v2's stricter validation rules.
• Added default values to required fields in several database configuration classes (MariaDB, PgVector) to ensure smooth validation when loading partial or legacy data.
• Updated validation logic to use Pydantic v2 features like field_validator and improved ValidationError handling from pydantic_core.
• Standardized the use of SecretStr for sensitive connection details (passwords, API keys) across all database clients.

2. Weaviate Client Upgrade (v3.x → v4.18.x)

• Refactored the WeaviateCloud client to use the new Weaviate v4 "Collections" API.
• Migrated connection logic to weaviate.connect_to_custom, utilizing both HTTP and gRPC endpoints for improved performance.
• Updated schema management and search queries to use the new weaviate.classes.config and fluent interface.
• Added a normalization layer in WeaviateCloud._ensure_cfg to support both legacy dict configurations and new WeaviateConfig models.

3. Backward Compatibility & Stability

• Result Loading Patch: Modified TestResult.read_file to inject default credentials (e.g., password: "-") for MariaDB, PgVector, and Weaviate when loading older result files. This prevents ValidationError when viewing historical data that omitted these fields.
• Robust Configuration Parsing: Added try-except blocks around db.case_config_cls instantiation to ensure that a single malformed result file doesn't prevent the results page from loading.

4. Streamlit UI Updates

• Addressed deprecation warnings by replacing use_container_width=True with width="stretch" across all chart and table components.
• Ensures full compatibility with future Streamlit releases (post 2025-12-31).

Verification Results

• Pydantic: Confirmed that version 2.12.5 correctly validates all current and legacy configuration models.
• Weaviate: Verified successful collection creation, data insertion, and search using the v4 client against a Weaviate instance.
• Compatibility: Confirmed that historical JSON result files for MariaDB and PgVector load correctly on the Results page.
• UI: Verified that charts and data editors correctly expand to container width using the new stretch parameter.

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[fer-marino]

mark it as draft please. There is still more pydantic work to do.

[XuanYang-cn]

@fer-marino great work! Please notify me if it's ready to review

[fer-marino]

this is ready for review. Anyway I've noticed that many test units fail. I'm not sure it depends on my code changes. It looks some are just outdated.