Errors galore

- Make everything in the compiler chain's results not null
- Throw errors immediately when encountered
- Log error messages when falling back
- Do not eagerly grab utility programs in IndirectDrawManager so we can
  actually catch errors and fall back
- Remove CompilerStats

common/src/backend/java/dev/engine_room/flywheel/backend/compile/FlwPrograms.java

@@ -6,7 +6,6 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import dev.engine_room.flywheel.api.Flywheel;
-import dev.engine_room.flywheel.backend.compile.core.CompilerStats;
 import dev.engine_room.flywheel.backend.glsl.ShaderSources;
 import dev.engine_room.flywheel.backend.glsl.SourceComponent;
 import net.minecraft.resources.ResourceLocation;
@@ -29,17 +28,9 @@ public final class FlwPrograms {
 
 		var sources = new ShaderSources(resourceManager);
 		SOURCES = sources;
-		var stats = new CompilerStats("ubershaders");
 
 		var fragmentComponentsHeader = sources.get(COMPONENTS_HEADER_FRAG);
 
-		// TODO: separate compilation for cutout OFF, but keep the rest uber'd?
-		if (stats.errored() || fragmentComponentsHeader == null) {
-			// Probably means the shader sources are missing.
-			stats.emitErrorLog();
-			return;
-		}
-
 		List<SourceComponent> vertexComponents = List.of();
 		List<SourceComponent> fragmentComponents = List.of(fragmentComponentsHeader);
 

common/src/backend/java/dev/engine_room/flywheel/backend/compile/InstancingPrograms.java

@@ -43,7 +43,6 @@ public class InstancingPrograms extends AtomicReferenceCounted {
 			return;
 		}
 
-
 		var pipelineCompiler = PipelineCompiler.create(sources, Pipelines.INSTANCING, vertexComponents, fragmentComponents, EXTENSIONS);
 		InstancingPrograms newInstance = new InstancingPrograms(pipelineCompiler);
 

common/src/backend/java/dev/engine_room/flywheel/backend/compile/core/CompilationHarness.java

@@ -3,8 +3,6 @@ package dev.engine_room.flywheel.backend.compile.core;
 import java.util.HashMap;
 import java.util.Map;
 
-import org.jetbrains.annotations.Nullable;
-
 import dev.engine_room.flywheel.backend.gl.GlObject;
 import dev.engine_room.flywheel.backend.gl.shader.GlProgram;
 import dev.engine_room.flywheel.backend.glsl.ShaderSources;
@@ -14,16 +12,14 @@ public class CompilationHarness<K> {
 	private final KeyCompiler<K> compiler;
 	private final ShaderCache shaderCache;
 	private final ProgramLinker programLinker;
-	private final CompilerStats stats;
 
 	private final Map<K, GlProgram> programs = new HashMap<>();
 
 	public CompilationHarness(String marker, ShaderSources sources, KeyCompiler<K> compiler) {
 		this.sources = sources;
 		this.compiler = compiler;
-		stats = new CompilerStats(marker);
+		shaderCache = new ShaderCache();
-		shaderCache = new ShaderCache(stats);
+		programLinker = new ProgramLinker();
-		programLinker = new ProgramLinker(stats);
 	}
 
 	public GlProgram get(K key) {
@@ -31,14 +27,7 @@ public class CompilationHarness<K> {
 	}
 
 	private GlProgram compile(K key) {
-		var out = compiler.compile(key, sources, shaderCache, programLinker);
+		return compiler.compile(key, sources, shaderCache, programLinker);
-
-		if (out == null) {
-			// TODO: populate exception with error details
-			throw new ShaderException();
-		}
-
-		return out;
 	}
 
 	public void delete() {
@@ -51,6 +40,6 @@ public class CompilationHarness<K> {
 	}
 
 	public interface KeyCompiler<K> {
-		@Nullable GlProgram compile(K key, ShaderSources loader, ShaderCache shaderCache, ProgramLinker programLinker);
+		GlProgram compile(K key, ShaderSources loader, ShaderCache shaderCache, ProgramLinker programLinker);
 	}
 }

common/src/backend/java/dev/engine_room/flywheel/backend/compile/core/Compile.java

@@ -10,8 +10,6 @@ import java.util.function.BiFunction;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
-import org.jetbrains.annotations.Nullable;
-
 import dev.engine_room.flywheel.backend.compile.FlwPrograms;
 import dev.engine_room.flywheel.backend.gl.shader.GlProgram;
 import dev.engine_room.flywheel.backend.gl.shader.GlShader;
@@ -44,7 +42,7 @@ public class Compile<K> {
 	public static class ShaderCompiler<K> {
 		private final GlslVersion glslVersion;
 		private final ShaderType shaderType;
-		private final List<BiFunction<K, ShaderSources, @Nullable SourceComponent>> fetchers = new ArrayList<>();
+		private final List<BiFunction<K, ShaderSources, SourceComponent>> fetchers = new ArrayList<>();
 		private BiConsumer<K, Compilation> compilationCallbacks = ($, $$) -> {
 		};
 		private Function<K, String> nameMapper = Object::toString;
@@ -59,21 +57,21 @@ public class Compile<K> {
 			return this;
 		}
 
-		public ShaderCompiler<K> with(BiFunction<K, ShaderSources, @Nullable SourceComponent> fetch) {
+		public ShaderCompiler<K> with(BiFunction<K, ShaderSources, SourceComponent> fetch) {
 			fetchers.add(fetch);
 			return this;
 		}
 
-		public ShaderCompiler<K> withComponents(Collection<@Nullable SourceComponent> components) {
+		public ShaderCompiler<K> withComponents(Collection<SourceComponent> components) {
 			components.forEach(this::withComponent);
 			return this;
 		}
 
-		public ShaderCompiler<K> withComponent(@Nullable SourceComponent component) {
+		public ShaderCompiler<K> withComponent(SourceComponent component) {
 			return withComponent($ -> component);
 		}
 
-		public ShaderCompiler<K> withComponent(Function<K, @Nullable SourceComponent> sourceFetcher) {
+		public ShaderCompiler<K> withComponent(Function<K, SourceComponent> sourceFetcher) {
 			return with((key, $) -> sourceFetcher.apply(key));
 		}
 
@@ -122,22 +120,12 @@ public class Compile<K> {
 			});
 		}
 
-		@Nullable
 		private GlShader compile(K key, ShaderCache compiler, ShaderSources loader) {
 			long start = System.nanoTime();
 
 			var components = new ArrayList<SourceComponent>();
-			boolean ok = true;
 			for (var fetcher : fetchers) {
-				SourceComponent apply = fetcher.apply(key, loader);
+				components.add(fetcher.apply(key, loader));
-				if (apply == null) {
-					ok = false;
-				}
-				components.add(apply);
-			}
-
-			if (!ok) {
-				return null;
 			}
 
 			Consumer<Compilation> cb = ctx -> compilationCallbacks.accept(key, ctx);
@@ -182,7 +170,6 @@ public class Compile<K> {
 		}
 
 		@Override
-		@Nullable
 		public GlProgram compile(K key, ShaderSources loader, ShaderCache shaderCache, ProgramLinker programLinker) {
 			if (compilers.isEmpty()) {
 				throw new IllegalStateException("No shader compilers were added!");
@@ -192,24 +179,13 @@ public class Compile<K> {
 
 			List<GlShader> shaders = new ArrayList<>();
 
-			boolean ok = true;
 			for (ShaderCompiler<K> compiler : compilers.values()) {
-				var shader = compiler.compile(key, shaderCache, loader);
+				shaders.add(compiler.compile(key, shaderCache, loader));
-				if (shader == null) {
-					ok = false;
-				}
-				shaders.add(shader);
-			}
-
-			if (!ok) {
-				return null;
 			}
 
 			var out = programLinker.link(shaders, p -> preLink.accept(key, p));
 
-			if (out != null) {
 			postLink.accept(key, out);
-			}
 
 			long end = System.nanoTime();
 

common/src/backend/java/dev/engine_room/flywheel/backend/compile/core/CompilerStats.java

@@ -1,106 +0,0 @@
-package dev.engine_room.flywheel.backend.compile.core;
-
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-import java.util.stream.Collectors;
-
-import org.slf4j.Marker;
-import org.slf4j.MarkerFactory;
-
-import dev.engine_room.flywheel.backend.compile.FlwPrograms;
-import dev.engine_room.flywheel.backend.glsl.LoadError;
-import dev.engine_room.flywheel.backend.glsl.LoadResult;
-import dev.engine_room.flywheel.backend.glsl.error.ErrorBuilder;
-import dev.engine_room.flywheel.lib.util.StringUtil;
-
-public class CompilerStats {
-	private final Marker marker;
-	private long compileStart;
-
-	private final Set<LoadError> loadErrors = new HashSet<>();
-	private final List<FailedCompilation> shaderErrors = new ArrayList<>();
-	private final List<String> programErrors = new ArrayList<>();
-
-	private boolean errored = false;
-	private int shaderCount = 0;
-	private int programCount = 0;
-
-	public CompilerStats(String marker) {
-		this.marker = MarkerFactory.getMarker(marker);
-	}
-
-	public void start() {
-		compileStart = System.nanoTime();
-	}
-
-	public void finish() {
-		long compileEnd = System.nanoTime();
-		var elapsed = StringUtil.formatTime(compileEnd - compileStart);
-
-		FlwPrograms.LOGGER.info(marker, "Compiled %d programs (with %d link errors) and %d shaders (with %d compile errors) in %s".formatted(programCount, programErrors.size(), shaderCount, shaderErrors.size(), elapsed));
-	}
-
-	public boolean errored() {
-		return errored;
-	}
-
-	public void emitErrorLog() {
-		String out = "";
-
-		if (!loadErrors.isEmpty()) {
-			out += "\nErrors loading sources:\n" + loadErrors();
-		}
-
-		if (!shaderErrors.isEmpty()) {
-			out += "\nShader compilation errors:\n" + compileErrors();
-		}
-
-		if (!programErrors.isEmpty()) {
-			out += "\nProgram link errors:\n" + linkErrors();
-		}
-
-		FlwPrograms.LOGGER.error(marker, out);
-	}
-
-	private String compileErrors() {
-		return shaderErrors.stream()
-				.map(FailedCompilation::generateMessage)
-				.collect(Collectors.joining("\n"));
-	}
-
-	private String linkErrors() {
-		return String.join("\n", programErrors);
-	}
-
-	private String loadErrors() {
-		return loadErrors.stream()
-				.map(LoadError::generateMessage)
-				.map(ErrorBuilder::build)
-				.collect(Collectors.joining("\n"));
-	}
-
-	public void shaderResult(ShaderResult result) {
-		if (result instanceof ShaderResult.Failure f) {
-			shaderErrors.add(f.failure());
-			errored = true;
-		}
-		shaderCount++;
-	}
-
-	public void linkResult(LinkResult linkResult) {
-		if (linkResult instanceof LinkResult.Failure f) {
-			programErrors.add(f.failure());
-			errored = true;
-		}
-		programCount++;
-	}
-
-	public void loadResult(LoadResult loadResult) {
-		if (loadResult instanceof LoadResult.Failure f) {
-			loadErrors.add(f.error());
-			errored = true;
-		}
-	}
-}

common/src/backend/java/dev/engine_room/flywheel/backend/compile/core/LinkResult.java

@@ -1,15 +1,11 @@
 package dev.engine_room.flywheel.backend.compile.core;
 
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 import dev.engine_room.flywheel.backend.gl.shader.GlProgram;
 
 public sealed interface LinkResult {
-	@Nullable
+	GlProgram unwrap();
-	default GlProgram unwrap() {
-		return null;
-	}
 
 	record Success(GlProgram program, String log) implements LinkResult {
 		@Override
@@ -20,6 +16,10 @@ public sealed interface LinkResult {
 	}
 
 	record Failure(String failure) implements LinkResult {
+		@Override
+		public GlProgram unwrap() {
+			throw new ShaderException.Link(failure);
+		}
 	}
 
 	static LinkResult success(GlProgram program, String log) {

common/src/backend/java/dev/engine_room/flywheel/backend/compile/core/ProgramLinker.java

@@ -11,24 +11,17 @@ import static org.lwjgl.opengl.GL20.glLinkProgram;
 import java.util.List;
 import java.util.function.Consumer;
 
-import org.jetbrains.annotations.Nullable;
-
 import dev.engine_room.flywheel.backend.gl.shader.GlProgram;
 import dev.engine_room.flywheel.backend.gl.shader.GlShader;
 
 public class ProgramLinker {
-	private final CompilerStats stats;
 
-	public ProgramLinker(CompilerStats stats) {
+	public ProgramLinker() {
-		this.stats = stats;
 	}
 
-	@Nullable
 	public GlProgram link(List<GlShader> shaders, Consumer<GlProgram> preLink) {
 		// this probably doesn't need caching
-		var linkResult = linkInternal(shaders, preLink);
+		return linkInternal(shaders, preLink).unwrap();
-		stats.linkResult(linkResult);
-		return linkResult.unwrap();
 	}
 
 	private LinkResult linkInternal(List<GlShader> shaders, Consumer<GlProgram> preLink) {

common/src/backend/java/dev/engine_room/flywheel/backend/compile/core/ShaderCache.java

@@ -4,12 +4,9 @@ import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Objects;
 import java.util.Set;
 import java.util.function.Consumer;
 
-import org.jetbrains.annotations.Nullable;
-
 import dev.engine_room.flywheel.backend.gl.shader.GlShader;
 import dev.engine_room.flywheel.backend.gl.shader.ShaderType;
 import dev.engine_room.flywheel.backend.glsl.GlslVersion;
@@ -17,13 +14,10 @@ import dev.engine_room.flywheel.backend.glsl.SourceComponent;
 
 public class ShaderCache {
 	private final Map<ShaderKey, ShaderResult> inner = new HashMap<>();
-	private final CompilerStats stats;
 
-	public ShaderCache(CompilerStats stats) {
+	public ShaderCache() {
-		this.stats = stats;
 	}
 
-	@Nullable
 	public GlShader compile(GlslVersion glslVersion, ShaderType shaderType, String name, Consumer<Compilation> callback, List<SourceComponent> sourceComponents) {
 		var key = new ShaderKey(glslVersion, shaderType, name);
 		var cached = inner.get(key);
@@ -41,15 +35,14 @@ public class ShaderCache {
 
 		ShaderResult out = ctx.compile(shaderType, name);
 		inner.put(key, out);
-		stats.shaderResult(out);
 		return out.unwrap();
 	}
 
 	public void delete() {
 		inner.values()
 				.stream()
+				.filter(r -> r instanceof ShaderResult.Success)
 				.map(ShaderResult::unwrap)
-				.filter(Objects::nonNull)
 				.forEach(GlShader::delete);
 		inner.clear();
 	}

common/src/backend/java/dev/engine_room/flywheel/backend/compile/core/ShaderException.java

@@ -1,4 +1,57 @@
 package dev.engine_room.flywheel.backend.compile.core;
 
 public class ShaderException extends RuntimeException {
+	public ShaderException(String message) {
+		super(message);
+	}
+
+	public ShaderException(String message, Throwable cause) {
+		super(message, cause);
+	}
+
+	public ShaderException(Throwable cause) {
+		super(cause);
+	}
+
+	public static class Link extends ShaderException {
+		public Link(String message) {
+			super(message);
+		}
+
+		public Link(String message, Throwable cause) {
+			super(message, cause);
+		}
+
+		public Link(Throwable cause) {
+			super(cause);
+		}
+	}
+
+	public static class Compile extends ShaderException {
+		public Compile(String message) {
+			super(message);
+		}
+
+		public Compile(String message, Throwable cause) {
+			super(message, cause);
+		}
+
+		public Compile(Throwable cause) {
+			super(cause);
+		}
+	}
+
+	public static class Load extends ShaderException {
+		public Load(String message) {
+			super(message);
+		}
+
+		public Load(String message, Throwable cause) {
+			super(message, cause);
+		}
+
+		public Load(Throwable cause) {
+			super(cause);
+		}
+	}
 }

common/src/backend/java/dev/engine_room/flywheel/backend/compile/core/ShaderResult.java

@@ -1,25 +1,22 @@
 package dev.engine_room.flywheel.backend.compile.core;
 
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-
 import dev.engine_room.flywheel.backend.gl.shader.GlShader;
 
 public sealed interface ShaderResult {
-	@Nullable
+	GlShader unwrap();
-	default GlShader unwrap() {
-		return null;
-	}
 
 	record Success(GlShader shader, String infoLog) implements ShaderResult {
 		@Override
-		@NotNull
 		public GlShader unwrap() {
 			return shader;
 		}
 	}
 
 	record Failure(FailedCompilation failure) implements ShaderResult {
+		@Override
+		public GlShader unwrap() {
+			throw new ShaderException.Compile(failure.generateMessage());
+		}
 	}
 
 	static ShaderResult success(GlShader program, String infoLog) {

common/src/backend/java/dev/engine_room/flywheel/backend/engine/EngineImpl.java

@@ -13,6 +13,7 @@ import dev.engine_room.flywheel.api.task.Plan;
 import dev.engine_room.flywheel.api.visualization.VisualEmbedding;
 import dev.engine_room.flywheel.api.visualization.VisualType;
 import dev.engine_room.flywheel.api.visualization.VisualizationContext;
+import dev.engine_room.flywheel.backend.FlwBackend;
 import dev.engine_room.flywheel.backend.compile.core.ShaderException;
 import dev.engine_room.flywheel.backend.engine.embed.EmbeddedEnvironment;
 import dev.engine_room.flywheel.backend.engine.embed.Environment;
@@ -93,6 +94,7 @@ public class EngineImpl implements Engine {
 			environmentStorage.flush();
 			drawManager.flush(lightStorage, environmentStorage);
 		} catch (ShaderException e) {
+			FlwBackend.LOGGER.error("Falling back", e);
 			triggerFallback();
 		}
 	}
@@ -102,6 +104,7 @@ public class EngineImpl implements Engine {
 		try (var state = GlStateTracker.getRestoreState()) {
 			drawManager.render(visualType);
 		} catch (ShaderException e) {
+			FlwBackend.LOGGER.error("Falling back", e);
 			triggerFallback();
 		}
 	}
@@ -111,6 +114,7 @@ public class EngineImpl implements Engine {
 		try (var state = GlStateTracker.getRestoreState()) {
 			drawManager.renderCrumbling(crumblingBlocks);
 		} catch (ShaderException e) {
+			FlwBackend.LOGGER.error("Falling back", e);
 			triggerFallback();
 		}
 	}

common/src/backend/java/dev/engine_room/flywheel/backend/engine/indirect/DepthPyramid.java

@@ -5,23 +5,21 @@ import org.lwjgl.opengl.GL46;
 
 import com.mojang.blaze3d.platform.GlStateManager;
 
+import dev.engine_room.flywheel.backend.compile.IndirectPrograms;
 import dev.engine_room.flywheel.backend.gl.GlTextureUnit;
-import dev.engine_room.flywheel.backend.gl.shader.GlProgram;
 import dev.engine_room.flywheel.lib.math.MoreMath;
 import net.minecraft.client.Minecraft;
 
 public class DepthPyramid {
-	private final GlProgram downsampleFirstProgram;
+	private final IndirectPrograms programs;
-	private final GlProgram downsampleSecondProgram;
 
 	public int pyramidTextureId = -1;
 
 	private int lastWidth = -1;
 	private int lastHeight = -1;
 
-	public DepthPyramid(GlProgram downsampleFirstProgram, GlProgram downsampleSecondProgram) {
+	public DepthPyramid(IndirectPrograms programs) {
-		this.downsampleFirstProgram = downsampleFirstProgram;
+		this.programs = programs;
-		this.downsampleSecondProgram = downsampleSecondProgram;
 	}
 
 	public void generate() {
@@ -42,6 +40,7 @@ public class DepthPyramid {
 		GlTextureUnit.T0.makeActive();
 		GlStateManager._bindTexture(depthBufferId);
 
+		var downsampleFirstProgram = programs.getDownsampleFirstProgram();
 		downsampleFirstProgram.bind();
 		downsampleFirstProgram.setUInt("max_mip_level", mipLevels);
 
@@ -59,6 +58,7 @@ public class DepthPyramid {
 
 		GL46.glMemoryBarrier(GL46.GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
 
+		var downsampleSecondProgram = programs.getDownsampleSecondProgram();
 		downsampleSecondProgram.bind();
 		downsampleSecondProgram.setUInt("max_mip_level", mipLevels);
 

common/src/backend/java/dev/engine_room/flywheel/backend/engine/indirect/IndirectDrawManager.java

@@ -56,6 +56,8 @@ public class IndirectDrawManager extends DrawManager<IndirectInstancer<?>> {
 		this.programs = programs;
 		programs.acquire();
 
+		// WARN: We should avoid eagerly grabbing GlPrograms here as catching compile
+		// errors and falling back during construction is a bit more complicated.
 		stagingBuffer = new StagingBuffer(this.programs);
 		meshPool = new MeshPool();
 		vertexArray = GlVertexArray.create();
@@ -63,7 +65,7 @@ public class IndirectDrawManager extends DrawManager<IndirectInstancer<?>> {
 		lightBuffers = new LightBuffers();
 		matrixBuffer = new MatrixBuffer();
 
-		depthPyramid = new DepthPyramid(programs.getDownsampleFirstProgram(), programs.getDownsampleSecondProgram());
+		depthPyramid = new DepthPyramid(programs);
 	}
 
 	@Override

common/src/backend/java/dev/engine_room/flywheel/backend/engine/indirect/StagingBuffer.java

@@ -10,7 +10,6 @@ import org.lwjgl.system.MemoryUtil;
 import dev.engine_room.flywheel.backend.compile.IndirectPrograms;
 import dev.engine_room.flywheel.backend.gl.GlFence;
 import dev.engine_room.flywheel.backend.gl.buffer.GlBuffer;
-import dev.engine_room.flywheel.backend.gl.shader.GlProgram;
 import dev.engine_room.flywheel.lib.memory.FlwMemoryTracker;
 import dev.engine_room.flywheel.lib.memory.MemoryBlock;
 import it.unimi.dsi.fastutil.PriorityQueue;
@@ -26,6 +25,7 @@ public class StagingBuffer {
 	private final int vbo;
 	private final long map;
 	private final long capacity;
+	private final IndirectPrograms programs;
 
 	private final OverflowStagingBuffer overflow = new OverflowStagingBuffer();
 	private final TransferList transfers = new TransferList();
@@ -33,8 +33,6 @@ public class StagingBuffer {
 	private final GlBuffer scatterBuffer = new GlBuffer();
 	private final ScatterList scatterList = new ScatterList();
 
-	private final GlProgram scatterProgram;
-
 	/**
 	 * The position in the buffer at the time of the last flush.
 	 */
@@ -70,6 +68,7 @@ public class StagingBuffer {
 
 	public StagingBuffer(long capacity, IndirectPrograms programs) {
 		this.capacity = capacity;
+		this.programs = programs;
 		vbo = GL45C.glCreateBuffers();
 
 		GL45C.glNamedBufferStorage(vbo, capacity, STORAGE_FLAGS);
@@ -78,8 +77,6 @@ public class StagingBuffer {
 		totalAvailable = capacity;
 
 		FlwMemoryTracker._allocCpuMemory(capacity);
-
-		scatterProgram = programs.getScatterProgram();
 	}
 
 	/**
@@ -251,7 +248,8 @@ public class StagingBuffer {
 	 * <a href=https://on-demand.gputechconf.com/gtc/2016/presentation/s6138-christoph-kubisch-pierre-boudier-gpu-driven-rendering.pdf>this presentation</a>
 	 */
 	private void dispatchComputeCopies() {
-		scatterProgram.bind();
+		programs.getScatterProgram()
+				.bind();
 
 		// These bindings don't change between dstVbos.
 		GL45.glBindBufferBase(GL45C.GL_SHADER_STORAGE_BUFFER, 0, scatterBuffer.handle());

common/src/backend/java/dev/engine_room/flywheel/backend/glsl/LoadResult.java

@@ -1,22 +1,22 @@
 package dev.engine_room.flywheel.backend.glsl;
 
-import org.jetbrains.annotations.NotNull;
+import dev.engine_room.flywheel.backend.compile.core.ShaderException;
-import org.jetbrains.annotations.Nullable;
 
 public sealed interface LoadResult {
-	@Nullable
+	SourceFile unwrap();
-	default SourceFile unwrap() {
-		return null;
-	}
 
 	record Success(SourceFile source) implements LoadResult {
 		@Override
-		@NotNull
 		public SourceFile unwrap() {
 			return source;
 		}
 	}
 
 	record Failure(LoadError error) implements LoadResult {
+		@Override
+		public SourceFile unwrap() {
+			throw new ShaderException.Load(error.generateMessage()
+					.build());
+		}
 	}
 }

common/src/backend/java/dev/engine_room/flywheel/backend/glsl/ShaderSources.java

@@ -9,7 +9,6 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
-import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.VisibleForTesting;
 
 import dev.engine_room.flywheel.backend.compile.FlwPrograms;
@@ -50,7 +49,6 @@ public class ShaderSources {
 		return cache.computeIfAbsent(location, loc -> new LoadResult.Failure(new LoadError.ResourceError(loc)));
 	}
 
-	@Nullable
 	public SourceFile get(ResourceLocation location) {
 		return find(location).unwrap();
 	}