The Contours That Refused to Exist: A Three-Bug Pileup in a Flutter Noise Map

Short summary

A detailed debugging account of a Flutter app that visualizes urban noise pollution as a heatmap over Mapbox maps. The contour layer silently failed on certain Android devices due to three compounding bugs: Firestore integer-to-double type coercion poisoning bounding-box calculations, missing composite indexes causing empty snapshots in release builds, and async raster build timing colliding with Mapbox style reloads. Each bug was harmless alone but together produced a silent, non-crashing rendering failure.

• •Firestore int/double type coercion silently corrupted bounding-box calculations for the raster layer
• •Missing composite indexes caused empty snapshots in release builds without throwing errors
• •Async raster generation timing collided with Mapbox style reloads, causing the layer to never attach

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