LSP-407 ContractInferenceIndexKt: extract contract inference gist to a service class

GitOrigin-RevId: e064a340a5fc3576d7fa482d9c68ff545bfae68a

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/inference/ContractInferenceGist.kt

@@ -0,0 +1,38 @@
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.codeInspection.dataFlow.inference
+
+import com.intellij.openapi.application.ApplicationManager
+import com.intellij.openapi.components.Service
+import com.intellij.util.gist.GistManager
+import com.intellij.util.gist.PsiFileGist
+
+private const val VERSION = 14
+
+/**
+ * Holds the [PsiFileGist] for caching contract inference results.
+ * <p>
+ * This is a separate service to avoid accessing [GistManager] during static class initialization of [InferenceVisitor],
+ * which violates platform rules (class initialization must not depend on services).
+ * See LSP-407 to learn more.
+ */
+@Service
+internal class ContractInferenceGist {
+  val gist: PsiFileGist<Map<Int, MethodData>> get() = _gist
+  private val _gist: PsiFileGist<Map<Int, MethodData>>
+
+  constructor() {
+    _gist = GistManager.getInstance().newPsiFileGist(
+      /* id = */ "contractInference",
+      /* version = */ VERSION,
+      /* externalizer = */ MethodDataExternalizer,
+      /* calcData = */ { psiFile -> indexFile(psiFile.node.lighterAST) },
+    )
+  }
+
+  companion object {
+    @JvmStatic
+    fun getInstance(): ContractInferenceGist {
+      return ApplicationManager.getApplication().getService(ContractInferenceGist::class.java)
+    }
+  }
+}

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/inference/ContractInferenceIndex.kt

@@ -23,17 +23,13 @@ import com.intellij.psi.util.CachedValuesManager
 import com.intellij.util.gist.GistManager
 import java.util.*
 
-private val gist = GistManager.getInstance().newPsiFileGist("contractInference", 14, MethodDataExternalizer) { file ->
-  indexFile(file.node.lighterAST)
-}
-
-private fun indexFile(tree: LighterAST): Map<Int, MethodData> {
+internal fun indexFile(tree: LighterAST): Map<Int, MethodData> {
   val visitor = InferenceVisitor(tree)
   visitor.visitNode(tree.root)
   return visitor.result
 }
 
-internal data class ClassData(
+private data class ClassData(
   val hasSuper: Boolean,
   val hasPureInitializer: Boolean,
   val isFinal: Boolean,
@@ -206,6 +202,7 @@ public fun handleInconsistency(method: PsiMethodImpl, cachedData: MethodData, e:
   if (e is ProcessCanceledException) return e
 
   val file = method.containingFile
+  val gist = ContractInferenceGist.getInstance().gist
   val gistMap = gist.getFileData(file)
   GistManager.getInstance().invalidateData(file.viewProvider.virtualFile)
 
@@ -233,6 +230,7 @@ public fun handleInconsistency(method: PsiMethodImpl, cachedData: MethodData, e:
 public fun getIndexedData(method: PsiMethodImpl): MethodData? {
   val file = method.containingFile
   val map = CachedValuesManager.getCachedValue(file) {
+    val gist = ContractInferenceGist.getInstance().gist
     CachedValueProvider.Result.create(bindMethods(gist.getFileData(file), file), file)
   }
   return map[method]