fix : Auto-Tangents node with spread = 0 and preserve existing = true causes weird change

[Annonnymmousss]

closes #3822

Screen.Recording.2026-02-24.at.9.54.03.PM.mov

[gemini-code-assist]

Summary of Changes

Hello @Annonnymmousss, 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 resolves a specific bug within the Auto-Tangents node's functionality. The change ensures that when the spread parameter is zero and existing tangents are meant to be preserved, the node correctly passes through the original data without unintended alterations. This improves the predictability and correctness of vector manipulation operations under these specific conditions.

Highlights

• Bug Fix: Addressed an issue in the auto_tangents node where setting spread to 0 and preserve_existing to true would lead to an unexpected modification of the input source.
• Conditional Logic: Implemented a new conditional check at the beginning of the auto_tangents function to immediately return the original source if spread is 0 and preserve_existing is true, thus preventing further processing.

Changelog

• node-graph/nodes/vector/src/vector_nodes.rs
  • Fixed a bug in the auto_tangents function where spread = 0 and preserve_existing = true caused an incorrect change to the source data.

Activity

• No specific activity (comments, reviews, or progress updates) has been recorded for this pull request yet.

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[gemini-code-assist]

Code Review

The pull request addresses an issue where the Auto-Tangents node produced unexpected results when spread was 0 and preserve_existing was true. The proposed change introduces an early return for this specific combination of parameters. However, this early return alters the intended behavior for points with zero-length handles, preventing them from being correctly converted to sharp corners.

[gemini-code-assist]

The added if statement introduces a functional change that deviates from the expected behavior of spread = 0. (sharp corner) when preserve_existing is true.

If spread is 0. and preserve_existing is true, the existing logic (lines 911-929) correctly handles two scenarios:

1. Points with non-zero existing handles are preserved (due to preserve_existing).
2. Points with zero-length existing handles (i.e., handles at the anchor position) are explicitly set to None (due to spread = 0.), making them sharp corners.

The current early return return source; prevents scenario 2 from occurring. This means if a point has a handle that is exactly at its anchor position, it will not be removed, which contradicts the "sharp corner" definition of spread = 0..

To maintain the correct behavior, this early return should be removed, allowing the subsequent logic to process all points as intended.

[Annonnymmousss]

make sense