Fixes race condition where incomplete state of ViewModelLines could be observed by events fired during model access. #285602
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…e observed by events fired during model access.
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Pull request overview
This PR fixes a critical race condition in ViewModelLinesFromProjectedModel._constructLines() where the modelLineProjections array was cleared and rebuilt incrementally. During reconstruction, synchronous callbacks from model operations could fire and attempt to access the incomplete array, causing "Cannot read properties of undefined" errors when calling methods like getViewLineMinColumn, getViewLineContent, or getViewLineMaxColumn.
Key Changes
- Build projections in a local
newProjectionsarray instead of directly updatingthis.modelLineProjections - Atomically replace
this.modelLineProjectionsonly after all projections are built, preventing callbacks from observing partially updated state
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Problem description
During _constructLines(), the modelLineProjections array was emptied (this.modelLineProjections = [])
While reconstructing (40+ lines of code), synchronous callbacks could fire from model operations
These callbacks tried to access modelLineProjections[index] which was empty/incomplete
Result: Cannot read properties of undefined (reading 'getViewLineMinColumn'|'getViewLineContent'|'getViewLineMaxColumn')
Potentially fixes the following issues
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