RenderLineLayer::render() exception due to missing GeometryTile.iconAltas patterns

[timbaker]

This bug is reproducible using commit 4a858eb.

This is the an example of a line-layer style causing the issue:

        {
            "type": "line",
            "paint": {
                "line-pattern": [
                    "step", ["zoom"],
                    "line_solid_6",
                    15, "line_double_14",
                    16, "line_double_16"
                ],

The exception occurs in RenderLineLayer::render() due to geometryTile.getPattern() returning empty results sometimes. GeometryTile.iconAtlas does not include the required pattern images.

          optional<ImagePosition> posA = geometryTile.getPattern(linePatternValue.from);
          optional<ImagePosition> posB = geometryTile.getPattern(linePatternValue.to);

GeometryTileWorker::parse() calls RenderLineLayer::createLayout() which creates a new PatternLayout.
The PatternLayout constructor is returning patternDependencies for a certain zoom level (during the layout stage), but rendering may later be performed at a different zoom level requiring different patterns.

The solution seems to be either:

1. The PatternLayout constructor would need to return the patterns at every zoom level, or
2. RenderLineLayer::render() would need to evaluate() again at whatever zoom level GeometryTileWorker::parse() used when it created the PatternLayout.

Note: I'm seeing this using a VectorSource. The TilePyramid appears to contain tiles between zoom levels 11-15 when rendering occurs at zoom=15. So the results of a PatternLayout created for zoom=11 being rendered at zoom=15 results in this error.

[timbaker]

Here is a style.json, xxx.geojson and sprites/ folder to demonstrate the bug.
I've tested it using mbgl-qt.exe from the Qt SDK. The map data is near lat=-0.05 long=0.05.
There's a maki symbol there, if you zoom out you should see it.

Zooming in/out and scrolling around near zoom=15 should cause exceptions in RenderLineLayer::render().

line-pattern-bug.zip

[brunoabinader]

@timbaker I couldn't reproduce the issue using the latest master (b83030a). Given the initial commit you've suggested, I suppose this has been fixed in #13535 (/cc @ChrisLoer). Could you please verify using the latest master?

[timbaker]

I get the same error after updating. I think the change made for SymbolBucket here #13667 needs to be done for LineBucket also.

[kkaefer]

Fixed in #14230