feat:Supports Switch plugin

[duhanmin]

Summary by CodeRabbit

• New Features
  • Added Switch component for routing input messages to corresponding outputs based on text comparison, supporting both Message and Data inputs with dynamic output generation based on defined cases.

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Walkthrough

New SwitchComponent introduced for flow control that routes an input message to designated outputs based on text-based case comparison. Includes input handling for Message/Data types, case matching logic, error handling, and dynamic output generation.

Changes

Cohort / File(s)	Summary
New Switch Flow Control Component src/lfx/src/lfx/components/flow_controls/switch.py	Introduces SwitchComponent class with inputs (switch, switch_key, cases) and dynamic grouped output. Implements case-based routing via _build_results, output building with build_output, and dynamic output management via update_outputs. Includes error handling for missing case key specifications in Data inputs.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

• Input extraction logic: Message/Data type handling and switch_key validation
• Case matching mechanism: Iteration and output index mapping logic
• Dynamic output generation: Ensure output count correctly synchronizes with cases length
• Error handling: Verify ValueError raised appropriately for missing case keys
• Async execution flow: Review _build_results async implementation and result storage/artifact handling

Pre-merge checks and finishing touches

Important

Pre-merge checks failed

Please resolve all errors before merging. Addressing warnings is optional.

❌ Failed checks (1 error, 3 warnings, 1 inconclusive)

Check name	Status	Explanation	Resolution
Test Coverage For New Implementations	❌ Error	PR introduces SwitchComponent without corresponding unit tests in the established test directory structure.	Create test_switch.py at ./src/backend/tests/unit/components/flow_controls/ following existing component test patterns with comprehensive coverage.
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.
Test Quality And Coverage	⚠️ Warning	SwitchComponent at src/lfx/src/lfx/components/flow_controls/switch.py lacks a corresponding test file, violating Langflow's testing standards which require test_<file_name>.py pattern and TestComponent classes for all components.	Create src/backend/tests/unit/components/flow_controls/test_switch.py with TestSwitchComponent class inheriting from ComponentTestBaseWithoutClient, including async test methods for _build_results, case matching, output generation, error handling, and edge cases.
Test File Naming And Structure	⚠️ Warning	Pull request introduces SwitchComponent without corresponding test file or proper module exports following established project patterns.	Create test_switch.py following repository patterns and add SwitchComponent to flow_controls init.py exports.
Excessive Mock Usage Warning	❓ Inconclusive	SwitchComponent PR lacks test files for proper mock usage assessment.	Create test file at src/backend/tests/unit/components/flow_controls/test_switch.py following snake_case naming pattern and Langflow guidelines.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'feat:Supports Switch plugin' directly describes the main change—introduction of a new SwitchComponent for routing messages. It is concise, specific, and clearly summarizes the primary feature addition.

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[coderabbitai]

Actionable comments posted: 6

🧹 Nitpick comments (1)

src/lfx/src/lfx/components/flow_controls/switch.py (1)

46-76: Consider additional edge case handling.

The current implementation may not handle these edge cases gracefully:

1. Empty cases list: If self.cases is empty, the loop won't execute and output_name stays None.
2. None value extraction: If self.switch is neither Message nor Data, value remains None and might not match cases as expected.
3. Type mismatches: The comparison value == case uses strict equality, which might not work as expected if types differ (e.g., "123" vs 123).

Consider adding validation:

• Ensure cases is non-empty
• Validate that value was successfully extracted
• Consider type coercion or explicit type handling for case comparisons

📜 Review details

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 0b3794f and 6b61fc7.

📒 Files selected for processing (1)

• src/lfx/src/lfx/components/flow_controls/switch.py (1 hunks)

🧰 Additional context used

🧠 Learnings (1)

📚 Learning: 2025-11-24T19:46:09.104Z

Learnt from: CR
Repo: langflow-ai/langflow PR: 0
File: .cursor/rules/backend_development.mdc:0-0
Timestamp: 2025-11-24T19:46:09.104Z
Learning: Applies to src/backend/base/langflow/components/**/*.py : Add new components to the appropriate subdirectory under `src/backend/base/langflow/components/` (agents/, data/, embeddings/, input_output/, models/, processing/, prompts/, tools/, or vectorstores/)

Applied to files:

• src/lfx/src/lfx/components/flow_controls/switch.py

🧬 Code graph analysis (1)

src/lfx/src/lfx/components/flow_controls/switch.py (3)

src/lfx/src/lfx/schema/data.py (1)

• Data (26-288)

src/lfx/src/lfx/schema/message.py (1)

• Message (34-315)

src/lfx/src/lfx/custom/custom_component/component.py (7)

• _pre_run_setup_if_needed (1171-1173)
• _handle_tool_mode (1175-1179)
• _get_outputs_to_process (1191-1219)
• _get_output_result (1221-1253)
• _build_artifact (1273-1287)
• _log_output (1310-1313)
• _finalize_results (1315-1319)

🪛 GitHub Actions: Ruff Style Check

src/lfx/src/lfx/components/flow_controls/switch.py

[error] 39-39: F541 f-string without any placeholders. Ruff check failed during 'uv run --only-dev ruff check --output-format=github .'

🪛 GitHub Check: Ruff Style Check (3.13)

src/lfx/src/lfx/components/flow_controls/switch.py

[failure] 89-89: Ruff (F541)
src/lfx/src/lfx/components/flow_controls/switch.py:89:28: F541 f-string without any placeholders

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[failure] 81-81: Ruff (ARG002)
src/lfx/src/lfx/components/flow_controls/switch.py:81:68: ARG002 Unused method argument: field_value

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[failure] 57-57: Ruff (RUF001)
src/lfx/src/lfx/components/flow_controls/switch.py:57:60: RUF001 String contains ambiguous ’ (RIGHT SINGLE QUOTATION MARK). Did you mean ``` (GRAVE ACCENT)?

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[failure] 57-57: Ruff (RUF001)
src/lfx/src/lfx/components/flow_controls/switch.py:57:55: RUF001 String contains ambiguous ‘ (LEFT SINGLE QUOTATION MARK). Did you mean ``` (GRAVE ACCENT)?

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[failure] 57-57: Ruff (EM101)
src/lfx/src/lfx/components/flow_controls/switch.py:57:34: EM101 Exception must not use a string literal, assign to variable first

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[failure] 57-57: Ruff (TRY003)
src/lfx/src/lfx/components/flow_controls/switch.py:57:23: TRY003 Avoid specifying long messages outside the exception class

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[failure] 56-56: Ruff (Q000)
src/lfx/src/lfx/components/flow_controls/switch.py:56:62: Q000 Single quotes found but double quotes preferred

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[failure] 41-41: Ruff (F541)
src/lfx/src/lfx/components/flow_controls/switch.py:41:20: F541 f-string without any placeholders

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[failure] 40-40: Ruff (F541)
src/lfx/src/lfx/components/flow_controls/switch.py:40:18: F541 f-string without any placeholders

---

[failure] 39-39: Ruff (F541)
src/lfx/src/lfx/components/flow_controls/switch.py:39:26: F541 f-string without any placeholders

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)

• GitHub Check: Update Component Index

🔇 Additional comments (4)

src/lfx/src/lfx/components/flow_controls/switch.py (4)

1-14: LGTM! Clear component metadata.

The imports and class metadata are well-structured and appropriately describe the component's purpose.

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15-35: LGTM! Well-defined inputs.

The input configuration appropriately handles both Message and Data types, with clear semantics for the switch key and case list.

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78-79: LGTM! Appropriate pass-through behavior.

The method correctly returns the underlying data dict, allowing the component to route the input data unchanged to the selected output.

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9-13: Verify component placement in the repository structure.

According to project conventions, new components should be added to appropriate subdirectories under src/backend/base/langflow/components/. However, this file is located at src/lfx/src/lfx/components/flow_controls/.

Please confirm that this location is correct for the lfx module structure, or if it should be moved to align with the standard component organization.

Based on learnings, components are typically organized under subdirectories like agents/, data/, embeddings/, etc.