Handle BLOCK_CREATE events for nested blocks in snippets

[tracygardner]

Summary

This PR fixes handling of lifecycle events for blocks that are created as part of a snippet creation. Previously, blocks nested inside a snippet's root block would not properly handle their creation events because the event's blockId field only contains the root block's ID, not the nested blocks' IDs.

Key Changes

• Added detection for BLOCK_CREATE events where the current block's ID is in the changeEvent.ids array (indicating the block was created as part of a multi-block creation like snippet instantiation)
• Updated lifecycle event handling in three locations (blocks/models.js and blocks/blocks.js) to trigger handleMeshLifecycleChange for both:
  • Direct block events (where changeEvent.blockId === block.id)
  • Nested block creation events (where the block ID is in changeEvent.ids)
• Applied consistent logic across all affected block model definitions

Implementation Details

The fix introduces a reusable check that validates:

1. The event type is Blockly.Events.BLOCK_CREATE
2. The event has an ids array property
3. The current block's ID is included in that array

This allows blocks to properly initialize their mesh lifecycle state when created as part of a snippet, ensuring consistent behavior whether a block is created individually or as part of a larger structure.

https://claude.ai/code/session_01FZ6vktw81VhbPuv9QePcJE

Summary by CodeRabbit

• Bug Fixes
  • Improved block lifecycle handling so mesh lifecycle updates are detected for blocks created directly or as part of nested/snippet creations, ensuring consistent behavior for newly created or moved blocks.
  • Allow mesh creation to proceed during loading when the change event is marked for undo, preserving expected undo/redo behavior during load.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 0abd3a3f-fb2b-4fc4-b7ba-15c8b6d9397b

📥 Commits

Reviewing files that changed from the base of the PR and between 91ed3e6 and 169eb10.

📒 Files selected for processing (1)

• ui/blockmesh.js

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📝 Walkthrough

Walkthrough

Lifecycle handling extended so BLOCK_CREATE events that include the current block's ID in changeEvent.ids are treated like direct targets; mesh lifecycle handlers now trigger when changeEvent.blockId === id OR the block was created as part of a snippet (present in ids).

Changes

Cohort / File(s)	Summary
Block lifecycle logic blocks/blocks.js, blocks/models.js	Added isThisBlockCreated detection for BLOCK_CREATE (checks changeEvent.ids includes the block's id) and expanded conditionals to call handleMeshLifecycleChange when changeEvent.blockId === id OR the block was created within a snippet. No public API changes.
Load-time/undo gating ui/blockmesh.js	Broadened early-return in updateOrCreateMeshFromBlock: it now only short-circuits when window.loadingCode is true AND changeEvent.recordUndo is falsy, allowing mesh creation to proceed during loading when the event records an undo. Existing disposed check unchanged.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 I nibble on changes, tidy and neat,
When snippets birth blocks, the lifecycle meets,
IDs hop in line, the mesh blinks awake,
Small code-footsteps over logic's greenake,
🥕✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ 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 accurately describes the main change: fixing lifecycle event handling for blocks created as part of snippet instantiation by detecting BLOCK_CREATE events for nested blocks.

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✨ Finishing Touches

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• Commit unit tests in branch claude/fix-nested-mesh-visibility-9eedJ

📝 Coding Plan

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