chore: use from __future__ import annotations

[sarxxt]

Summary

Fixes: #24303. This PR refactors type annotations across the codebase by enabling from __future__ import annotations and replacing quoted type annotations (e.g. "T") with direct references (T). This is a refactor-only change with no functional or behavioral impact. The goal is to simplify type hints and improve readability and
maintainability.

Testing

• Ran backend locally to ensure the application starts and imports correctly
• Verified no syntax or runtime errors after refactoring

Screenshots

Before	After
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Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods

[gemini-code-assist]

Summary of Changes

Hello @sarxxt, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request focuses on a significant code quality improvement by modernizing Python type annotations. By consistently applying from __future__ import annotations and removing string-based forward references, the codebase becomes more aligned with current Python best practices for type hinting. This change is purely an internal refactor aimed at enhancing the developer experience and long-term maintainability without altering any application behavior.

Highlights

• Type Annotation Refactoring: This pull request refactors type annotations across the codebase by enabling from __future__ import annotations in numerous Python files.
• Improved Readability: Quoted type annotations (e.g., "T") have been replaced with direct references (T), simplifying type hints and improving code readability and maintainability.
• No Functional Impact: This is a refactor-only change with no functional or behavioral impact on the application, ensuring stability while enhancing code quality.

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[gemini-code-assist]

Code Review

This pull request is a great refactoring that modernizes the codebase by using from __future__ import annotations and removing quoted type hints. The changes are clean and improve readability.

I've found a recurring issue where some type hints, after being unquoted, rely on imports that are still inside if TYPE_CHECKING: blocks. This can lead to NameError at runtime when type hints are inspected. I've left comments on the specific occurrences I found. Please ensure all necessary imports are moved out of TYPE_CHECKING blocks to be available at runtime.

Overall, this is a valuable improvement. Keep up the great work!

[diffray-bot]

Changes Summary

This PR implements PEP 563 (from future import annotations) across 50 backend API files, enabling unquoted type annotations throughout the codebase. This is a pure refactoring that improves code readability and maintainability without any functional changes.

Type: refactoring

Components Affected: Core Entities (datasource, mcp_provider, provider_entities, message_entities, model_entities, etc.), Core Tools (builtin_tool, custom_tool, mcp_tool, plugin_tool, workflow_as_tool), Workflow System (nodes, graph, graph_engine, runtime, entities, repositories), RAG/Datasource (clickzetta_vector, dataset_docstore, queue), Models (workflow, provider, tools, model), Extensions (logstore, clickzetta_volume), Libraries (broadcast_channel, email_i18n), Tests (mock_config, tool_node tests)

Files Changed

File	Summary	Change	Impact
...core/datasource/entities/datasource_entities.py	Added 'from future import annotations' and removed 30+ quoted type annotations	✏️	🟢
api/core/workflow/nodes/llm/node.py	Added 'from future import annotations' and unquoted type hints (File, GraphInitParams, GraphRuntimeState)	✏️	🟢
api/models/workflow.py	Added 'from future import annotations', removed Optional/Union imports (replaced with	syntax), unquoted return types	✏️
api/core/workflow/graph/graph.py	Added 'from future import annotations' and unquoted 5+ type annotations (NodeFactory, GraphBuilder, Graph)	✏️	🟢
.../core/workflow/graph_engine/test_mock_config.py	Added 'from future import annotations' and unquoted return types for builder methods	✏️	🟢

_{Full review in progress... | Powered by diffray}

[sarxxt]

@asukaminato0721 do I need to make any updates? The comments showing are not based on the changes I made some are due the changes in these file.