Logs: add check for missing Java members

module-log-parser/src/main/kotlin/org/quiltmc/community/cozy/modules/logs/config/SimpleLogParserConfig.kt

@@ -58,6 +58,7 @@ public class SimpleLogParserConfig(private val builder: Builder) : LogParserConf
 			QuiltLibrariesVersionProcessor(),
 			QuiltLoaderVersionProcessor(),
 			UnknownModProcessor(),
+			MissingItemProcessor(),
 		)
 
 		public var retrievers: MutableList<LogRetriever> = mutableListOf(

module-log-parser/src/main/kotlin/org/quiltmc/community/cozy/modules/logs/processors/MissingItemProcessor.kt

@@ -0,0 +1,91 @@
+package org.quiltmc.community.cozy.modules.logs.processors
+
+import org.quiltmc.community.cozy.modules.logs.data.Log
+import org.quiltmc.community.cozy.modules.logs.data.Order
+import org.quiltmc.community.cozy.modules.logs.types.LogProcessor
+
+// ClassNotFoundException: package.name.ClassName
+private val CLASS_REGEX =
+	"""java\.lang\.ClassNotFoundException: ((?:[^\n.]\.)*)([^\n.]+)"""
+	.toRegex(RegexOption.IGNORE_CASE)
+
+// NoSuchMethodError: 'ReturnType package.name.ClassName.methodName(ParamType, ParamType, ParamType)'
+private val METHOD_REGEX =
+	"""java\.lang\.NoSuchMethodError: '([^\n]+) ((?:[^\n.]\.)*)([^\n.]+)\.([^\n.]+)\.([^\n(]+)\(([^)]*)\)"""
+	.toRegex(RegexOption.IGNORE_CASE)
+
+// This is the new format for NoSuchFieldError (the old one has no useful information)
+// NoSuchFieldError: Class package.name.ClassName does not have member field 'Type fieldName'
+private val FIELD_REGEX =
+	"""java\.lang\.NoSuchFieldError: Class ((?:[^\n.]\.)*)([^\n.]+) does not have member field '([^\n]+)'"""
+	.toRegex(RegexOption.IGNORE_CASE)
+
+public class MissingItemProcessor : LogProcessor() {
+	override val identifier: String = "missing-jvm-elements"
+	override val order: Order = Order.Default
+
+	@Suppress("MagicNumber")
+	override suspend fun process(log: Log) {
+		val classMatches = CLASS_REGEX.findAll(log.content).toList()
+		val methodMatches = METHOD_REGEX.findAll(log.content).toList()
+		val fieldMatches = FIELD_REGEX.findAll(log.content).toList()
+
+		val packages = mutableSetOf<String>()
+		val topLevelClasses = mutableSetOf<String>()
+
+		for (match in classMatches) {
+			val pkg = match.groupValues[1]
+			if (pkg.isNotBlank()) {
+				packages.add(pkg)
+			} else {
+				topLevelClasses.add(match.groupValues[2])
+			}
+		}
+
+		for (match in methodMatches) {
+			val pkg = match.groupValues[2]
+			if (pkg.isNotBlank()) {
+				packages.add(pkg)
+			} else {
+				topLevelClasses.add(match.groupValues[3])
+			}
+		}
+
+		for (match in fieldMatches) {
+			val pkg = match.groupValues[1]
+			if (pkg.isNotBlank()) {
+				packages.add(pkg)
+			} else {
+				topLevelClasses.add(match.groupValues[2])
+			}
+		}
+
+		if (packages.isNotEmpty()) {
+			log.addMessage(
+				buildString {
+					append(
+						"**Some packages did not contain all required classes, fields, or methods. " +
+						"This is usually caused by a missing dependency.**\n"
+					)
+					for (pkg in packages) {
+						append("- `$pkg`\n")
+					}
+				}
+			)
+		}
+
+		if (topLevelClasses.isNotEmpty()) {
+			log.addMessage(
+				buildString {
+					append(
+						"**Some top-level classes were not found or were missing fields or methods. " +
+						"This is usually caused by a missing dependency.**\n"
+					)
+					for (cls in topLevelClasses) {
+						append("- `$cls`\n")
+					}
+				}
+			)
+		}
+	}
+}