feat: support tool multi-select input

[hjlarry]

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Summary

to resolve #29180

depends on langgenius/dify-plugin-sdks#258
depends on langgenius/dify-plugin-daemon#523

Screenshots

test locally:

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 @hjlarry, 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 introduces comprehensive support for multi-select inputs across the Dify platform, specifically for tool parameters. It involves significant updates to both the backend's data models and validation logic to accommodate list-based values, as well as corresponding frontend changes to define, render, and manage these new multi-selection capabilities within the user interface. This enhancement provides greater flexibility in configuring tools and workflows.

Highlights

• Backend Parameter Model Enhancement: The PluginParameter model in the backend has been updated to include a multiple boolean field, indicating if a parameter supports multi-selection, and now allows list as a valid type for default values.
• Backend Value Casting and Validation: The cast_parameter_value function now correctly handles list inputs for string-based parameter types, and the ToolInput validation logic has been extended to accept list values for constant tool inputs.
• Frontend Form Schema Update: The CredentialFormSchemaBase type in the frontend now includes an optional multiple property, enabling the definition of multi-select fields in forms.
• Frontend UI Component Logic: The FormInputItem component has been enhanced to correctly map multi-select inputs to VarType.array and to filter for appropriate array-related variable types, ensuring proper UI behavior and data binding.

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[gemini-code-assist]

Code Review

This pull request introduces support for multi-select inputs in tools, a valuable feature enhancement. The changes are well-distributed across the Python backend and TypeScript frontend to handle list-based parameter values. The implementation is logical and covers the necessary modifications to data models and value handling. I have a couple of minor suggestions to improve code conciseness in the backend and type safety in the frontend.

[Copilot]

Pull request overview

This PR adds multi-select input support for tool parameters, enabling users to select multiple values from select and dynamic-select fields in workflow tool configurations. The implementation spans both frontend (TypeScript/React) and backend (Python), adding the ability to handle array values for tool parameters that have the multiple flag enabled.

Key Changes

• Extended type system to support list/array values for multi-select tool parameters
• Updated frontend variable type mapping to treat multi-select inputs as array types
• Modified backend validation to accept list values in constant-type tool parameters

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
web/app/components/workflow/nodes/_base/components/form-input-item.tsx	Added logic to map multi-select inputs to VarType.array and filter for array variable types when isMultipleSelect is true
web/app/components/header/account-setting/model-provider-page/declarations.ts	Added optional multiple field to CredentialFormSchemaBase type definition
api/core/workflow/nodes/tool/entities.py	Extended constant type validation to accept list in addition to string, int, float, bool, and dict
api/core/plugin/entities/parameters.py	Added multiple field to PluginParameter model and updated cast_parameter_value to handle list values for SELECT/DYNAMIC_SELECT types

[Copilot]

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

[crazywoola]

cc @Yeuoly