reverse-engineering-anything/src/application/javascript/JavaScriptSemanticGraphBuilder.ts

import {
  createJavaScriptSemanticGraph,
  sealTransferredJavaScriptSemanticGraphSteps,
  type JavaScriptSemanticGraph,
} from "../../domain/javascript/javascriptSemanticGraph.js";
import type {
  JavaScriptSemanticFingerprint,
  JavaScriptSemanticGraphNode,
} from "../../domain/javascript/javascriptSemanticGraphSchemas.js";
import {
  JAVASCRIPT_SEMANTIC_RELATION_FAMILIES,
  JAVASCRIPT_SEMANTIC_RELATION_FAMILY,
} from "../../domain/javascript/javascriptSemanticGraphSchemas.js";
import type {
  JavaScriptSemanticCallArgument,
  JavaScriptSemanticIr,
} from "../../domain/javascript/javascriptSemanticIr.js";
import { sourceRangesEqual as rangesEqual } from "../../domain/javascript/javascriptStaticAnalysisHelpers.js";
import type { JavaScriptApplicationGraph } from "../../domain/javascript/javascriptApplicationGraph.js";
import type { JavaScriptArtifactAnalysis } from "./JavaScriptArtifactAnalysisTypes.js";
import type { JavaScriptArtifactFile } from "../../domain/javascript/javascriptArtifactFiles.js";
import {
  projectSemanticEvents,
  projectSemanticTimers,
} from "./JavaScriptSemanticGraphAsyncProjection.js";
import { projectSemanticChildProcesses } from "./JavaScriptSemanticGraphChildProcessProjection.js";
import {
  projectSemanticBoundaries,
  projectSemanticConfiguration,
  projectSemanticRequests,
} from "./JavaScriptSemanticGraphDataProjection.js";
import { projectSemanticResources } from "./JavaScriptSemanticGraphResourceProjection.js";
import { projectSemanticObjects } from "./JavaScriptSemanticGraphObjectProjection.js";
import { projectSemanticValues } from "./JavaScriptSemanticGraphValueProjection.js";
import { inferredSemanticEvidenceAt } from "./JavaScriptSemanticGraphEvidence.js";
import { projectSemanticFunctionFingerprints } from "./JavaScriptSemanticGraphFingerprintProjection.js";
import {
  projectSemanticClosureCaptures,
  projectSemanticFrontiers,
  projectSemanticPromises,
  projectSemanticReturnValues,
  type SemanticFlowProjectionContext,
} from "./JavaScriptSemanticGraphFlowProjection.js";
import {
  createSemanticCallableOwnerLookup,
  createSemanticCallSiteLookup,
  createSemanticNodeRangeLookup,
  semanticFamilyStatus,
} from "./JavaScriptSemanticGraphProjection.js";
import {
  addSemanticFallbackRoot as addFallbackRoot,
  retainSemanticGraphNode as retainNode,
  addSemanticGraphRelation as addRelation,
  createSemanticGraphProjectionState as emptyState,
  bindSemanticGraphApplicationNodes,
  type SemanticGraphProjectionState as BuilderState,
} from "./JavaScriptSemanticGraphConstruction.js";

interface BuilderInput {
  readonly rootArtifactSha256: string;
  readonly applicationGraph: Pick<
    JavaScriptApplicationGraph,
    "graph_id" | "nodes"
  >;
  readonly analysis: JavaScriptArtifactAnalysis;
}

interface FileContext extends SemanticFlowProjectionContext {
  readonly file: JavaScriptArtifactFile;
  readonly ir: JavaScriptSemanticIr;
  readonly state: BuilderState;
  readonly moduleNode: JavaScriptSemanticGraphNode;
  readonly bindingNodes: ReadonlyMap<string, JavaScriptSemanticGraphNode>;
  readonly callableNodes: ReadonlyMap<string, JavaScriptSemanticGraphNode>;
  readonly callSiteNodes: ReadonlyMap<string, JavaScriptSemanticGraphNode>;
  readonly returnSiteNodes: ReadonlyMap<string, JavaScriptSemanticGraphNode>;
  readonly argumentNodes: Map<string, JavaScriptSemanticGraphNode>;
  readonly referenceNodes: JavaScriptSemanticGraphNode[];
  readonly callResolutions: ReadonlyMap<string, "candidate" | "resolved">;
  readonly callableOwnerAt: ReturnType<
    typeof createSemanticCallableOwnerLookup
  >;
}

/**
 * Resource-safety ceiling on retained semantic nodes.
 *
 * The semantic projection emits one node per AST expression, call site, binding
 * and property slot. That is unbounded in input size. A small tree of five files
 * already yields on the order of 170,000 nodes, and larger trees yield millions,
 * exhausting the heap before the result can be serialized.
 *
 * This is a real resource-safety constraint, not a presentation preference, so
 * the ceiling is applied and reported through the graph's own `coverage` fields
 * (`truncated`, `omitted_nodes`, `omitted_relations`, `limits`) rather than
 * silently dropping data.
 *
 * Sizing: a retained semantic node costs roughly 3 KB once serialized, and V8
 * additionally caps a single string at 512 MB. The result is serialized after the
 * object graph is built and validated, so both phases must fit together. A single
 * minified vendor bundle can account for most of a tree's nodes, so a whole-tree
 * ceiling without a per-file ceiling does not bound the work. Both are applied.
 */
export const SEMANTIC_GRAPH_NODE_CEILING = 100_000;

/**
 * Per-file share of the semantic node budget.
 *
 * Bound each source file independently so one large bundled library cannot
 * consume the whole tree's budget and starve the application's own modules.
 */
export const SEMANTIC_GRAPH_FILE_NODE_CEILING = 20_000;

export const buildJavaScriptSemanticGraph = ({
  rootArtifactSha256,
  applicationGraph,
  analysis,
}: BuilderInput): JavaScriptSemanticGraph => {
  const projection = createJavaScriptSemanticGraphProjection();
  for (const analyzed of analysis.files) {
    if (analyzed.semantic !== null)
      projection.projectFile(analyzed.file, analyzed.semantic.ir);
  }
  return projection.finish(rootArtifactSha256, applicationGraph);
};

/** File-local semantic projection that does not retain consumed source IR. */
export interface JavaScriptSemanticGraphProjection {
  readonly projectFile: (
    file: JavaScriptArtifactFile,
    ir: JavaScriptSemanticIr,
  ) => void;
  /** Project one file in steps between its projection passes. */
  readonly projectFileSteps: (
    file: JavaScriptArtifactFile,
    ir: JavaScriptSemanticIr,
  ) => Generator<void, void>;
  readonly finish: (
    rootArtifactSha256: string,
    applicationGraph: BuilderInput["applicationGraph"],
  ) => JavaScriptSemanticGraph;
  readonly finishImmutableSteps: (
    rootArtifactSha256: string,
    applicationGraph: BuilderInput["applicationGraph"],
  ) => Generator<void, JavaScriptSemanticGraph>;
}

/** Accumulate semantic nodes while each source IR is still file-local. */
export const createJavaScriptSemanticGraphProjection =
  (): JavaScriptSemanticGraphProjection => {
    const state = emptyState({ nodes: [] });
    const fingerprints: JavaScriptSemanticFingerprint[] = [];
    let truncatedFiles = 0;
    const projectSourceSteps = function* (
      file: JavaScriptArtifactFile,
      ir: JavaScriptSemanticIr,
    ): Generator<void, void> {
      if (state.nodes.size >= SEMANTIC_GRAPH_NODE_CEILING) {
        truncatedFiles += 1;
        return;
      }
      const remainingTreeBudget =
        SEMANTIC_GRAPH_NODE_CEILING - state.nodes.size;
      state.fileNodeBudget = Math.min(
        SEMANTIC_GRAPH_FILE_NODE_CEILING,
        remainingTreeBudget,
      );
      state.fileNodesDropped = false;
      fingerprints.push(...(yield* projectFileSteps(file, ir, state)));
      // Nodes were dropped only if the budget actually blocked creation. A file
      // that exactly fills its share ends with a zero budget without dropping
      // anything, so the remaining budget alone cannot decide truncation.
      if (state.fileNodesDropped) truncatedFiles += 1;
      state.fileNodeBudget = null;
    };
    const finishWith = <Value>(
      factory: (input: unknown) => Value,
      rootArtifactSha256: string,
      applicationGraph: BuilderInput["applicationGraph"],
    ): Value => {
      bindSemanticGraphApplicationNodes(state, applicationGraph);
      if (state.roots.size === 0) addFallbackRoot(rootArtifactSha256, state);
      const relations = [...state.relations.values()];
      const unknowns = [...state.unknowns.values()];
      type Family = (typeof JAVASCRIPT_SEMANTIC_RELATION_FAMILIES)[number];
      const retainedByFamily = new Map<Family, number>();
      const unknownIdsByFamily = new Map<Family, string[]>();
      for (const relation of relations) {
        const family = JAVASCRIPT_SEMANTIC_RELATION_FAMILY[relation.relation];
        retainedByFamily.set(family, (retainedByFamily.get(family) ?? 0) + 1);
      }
      for (const unknown of unknowns) {
        const identifiers = unknownIdsByFamily.get(unknown.family);
        if (identifiers === undefined)
          unknownIdsByFamily.set(unknown.family, [unknown.unknown_id]);
        else identifiers.push(unknown.unknown_id);
      }
      const graph = factory({
        schema: "JavaScriptSemanticRelationGraph",
        root_artifact_sha256: rootArtifactSha256,
        application_graph_id: applicationGraph.graph_id,
        root_node_ids: [...state.roots],
        evidence_contexts: state.evidenceContexts.contexts,
        nodes: [...state.nodes.values()],
        relations,
        // The input is transferred to the factory; `fingerprints` is cleared below.
        fingerprints: [...fingerprints],
        unknowns,
        coverage: {
          status: truncatedFiles > 0 ? "partial" : "unknown",
          truncated: truncatedFiles > 0,
          omitted_nodes: truncatedFiles > 0 ? null : 0,
          omitted_relations: truncatedFiles > 0 ? null : 0,
          limits:
            truncatedFiles > 0
              ? [
                  {
                    name: "semantic_graph_node_ceiling",
                    value: SEMANTIC_GRAPH_NODE_CEILING,
                    unit: "items" as const,
                  },
                ]
              : [],
          families: JAVASCRIPT_SEMANTIC_RELATION_FAMILIES.map((family) => ({
            family,
            status: semanticFamilyStatus(family),
            retained_relations: retainedByFamily.get(family) ?? 0,
            omitted_relations: truncatedFiles > 0 ? null : 0,
            unknown_ids: unknownIdsByFamily.get(family) ?? [],
          })),
        },
        limitations: [
          "The semantic graph contains static syntax observations and conservative relationship candidates; it does not claim runtime execution.",
          "Local data flow does not claim control-flow-sensitive reaching definitions or arbitrary dynamic property resolution.",
          "Promise ownership covers explicit unshadowed Promise construction, static factories, aggregation, chaining, and await syntax only.",
          "Function fingerprints are static candidates; equal digests can remain ambiguous and do not prove behavioral equivalence.",
          "Event extraction covers EventEmitter-style literal registrations, removals, and dispatch candidates; dynamic names remain unknown.",
          "Timer extraction covers global or node:timers scheduling and exact local-handle cancellation.",
          "Child-process extraction covers asynchronous node:child_process creation, literal argv/env/stdio options, exit/error listeners, and kill signals.",
          "Configuration extraction covers process.env, process.argv, node:fs reads, and direct logical defaults.",
          "Request extraction covers fetch, WebSocket, node:http/node:https construction, direct option fields, and exact local response consumers.",
          "Boundary extraction covers unshadowed JSON/global coercions plus parse and validation method candidates.",
          "Resource extraction covers built-in filesystem/network acquisition and exact local close/destroy/end handles.",
        ],
      });
      state.nodes.clear();
      state.relations.clear();
      state.unknowns.clear();
      state.roots.clear();
      state.evidenceContexts.clear();
      fingerprints.length = 0;
      return graph;
    };
    return {
      projectFile: (file, ir) => {
        const steps = projectSourceSteps(file, ir);
        while (steps.next().done !== true);
      },
      projectFileSteps: projectSourceSteps,
      finish: (rootArtifactSha256, applicationGraph) =>
        finishWith(
          createJavaScriptSemanticGraph,
          rootArtifactSha256,
          applicationGraph,
        ),
      finishImmutableSteps: (rootArtifactSha256, applicationGraph) =>
        finishWith(
          sealTransferredJavaScriptSemanticGraphSteps,
          rootArtifactSha256,
          applicationGraph,
        ),
    };
  };

function* projectFileSteps(
  file: JavaScriptArtifactFile,
  ir: JavaScriptSemanticIr,
  state: BuilderState,
): Generator<void, JavaScriptSemanticFingerprint[]> {
  yield;
  const moduleNode = retainNode(state, file, {
    kind: "module",
    roleKey: "module",
    location: null,
    label: file.path,
    functionNodeId: null,
  });
  if (moduleNode === null) return [];
  state.roots.add(moduleNode.node_id);
  // Node creation keeps source order, which the per-file node budget relies
  // on; yields between nodes do not change it.
  const callableNodes = new Map<string, JavaScriptSemanticGraphNode>();
  for (const [index, callable] of ir.callables.entries()) {
    if (index % 64 === 0) yield;
    const node = retainNode(state, file, {
      kind: "function",
      roleKey: `callable:${callable.callableId}`,
      location: callable.location,
      label: callable.name,
      functionNodeId: null,
      // The label is display text; keep the exact name, which may be "".
      properties: { name: callable.name },
    });
    if (node !== null) callableNodes.set(callable.callableId, node);
  }
  const callableOwnerAt = createSemanticCallableOwnerLookup(ir, callableNodes);
  const bindingNodes = new Map<string, JavaScriptSemanticGraphNode>();
  for (const [index, binding] of ir.bindings.entries()) {
    if (index % 64 === 0) yield;
    const location = binding.definitions[0]?.location ?? null;
    const kind = binding.kind === "parameter" ? "parameter" : "binding";
    const owner = callableOwnerAt(location);
    const node = retainNode(state, file, {
      kind,
      roleKey: `binding:${binding.bindingId}`,
      location,
      label: binding.name,
      functionNodeId: owner?.node_id ?? null,
    });
    if (node !== null) bindingNodes.set(binding.bindingId, node);
  }
  const returnSiteNodes = yield* createReturnSiteNodes(
    file,
    ir,
    callableNodes,
    state,
  );
  const callSiteNodes = yield* createCallSiteNodes(
    file,
    ir,
    callableNodes,
    state,
  );
  const definitions: Omit<FileContext, "referenceNodesWithin"> = {
    file,
    ir,
    state,
    moduleNode,
    bindingNodes,
    callableNodes,
    callSiteNodes,
    returnSiteNodes,
    argumentNodes: new Map(),
    referenceNodes: [],
    callResolutions: new Map(
      ir.callSites.map((call) => [
        call.callSiteId,
        call.resolution === "exact" ? "resolved" : "candidate",
      ]),
    ),
    callableOwnerAt,
    callSiteAt: createSemanticCallSiteLookup(ir, callSiteNodes),
  };
  yield* projectDefinitionsAndReferences(definitions);
  const context: FileContext = {
    ...definitions,
    referenceNodesWithin: createSemanticNodeRangeLookup(
      definitions.referenceNodes,
    ),
  };
  // Each pass completes before the next starts, so yielding between passes
  // keeps projection order and results unchanged.
  for (const project of FILE_PROJECTION_PASSES) {
    yield;
    const steps = project(context);
    if (steps !== undefined) while (steps.next().done !== true) yield;
  }
  yield;
  return projectSemanticFunctionFingerprints(
    file,
    ir,
    callableNodes,
    state.evidenceContexts,
  );
}

function* createReturnSiteNodes(
  file: JavaScriptArtifactFile,
  ir: JavaScriptSemanticIr,
  callables: ReadonlyMap<string, JavaScriptSemanticGraphNode>,
  state: BuilderState,
): Generator<void, Map<string, JavaScriptSemanticGraphNode>> {
  const result = new Map<string, JavaScriptSemanticGraphNode>();
  for (const [index, callable] of ir.callables.entries()) {
    if (index % 64 === 0) yield;
    const owner = callables.get(callable.callableId);
    if (owner === undefined) continue;
    for (const site of callable.returnSites) {
      const identifier = site.returnSiteId;
      const node = retainNode(state, file, {
        kind: "return-site",
        roleKey: identifier,
        location: site.location,
        label: "return",
        functionNodeId: owner.node_id,
      });
      if (node !== null) result.set(identifier, node);
    }
  }
  return result;
}

function* createCallSiteNodes(
  file: JavaScriptArtifactFile,
  ir: JavaScriptSemanticIr,
  callables: ReadonlyMap<string, JavaScriptSemanticGraphNode>,
  state: BuilderState,
): Generator<void, Map<string, JavaScriptSemanticGraphNode>> {
  const result = new Map<string, JavaScriptSemanticGraphNode>();
  for (const [index, call] of ir.callSites.entries()) {
    if (index % 64 === 0) yield;
    const owner =
      call.callerCallableId === null
        ? null
        : (callables.get(call.callerCallableId)?.node_id ?? null);
    const node = retainNode(state, file, {
      kind: "call-site",
      roleKey: `call:${call.callSiteId}`,
      location: call.location,
      label: call.kind,
      functionNodeId: owner,
    });
    if (node !== null) result.set(call.callSiteId, node);
  }
  return result;
}

function* projectDefinitionsAndReferences(
  context: Omit<FileContext, "referenceNodesWithin">,
): Generator<void, void> {
  for (const [bindingIndex, binding] of context.ir.bindings.entries()) {
    if (bindingIndex % 64 === 0) yield;
    const bindingNode = context.bindingNodes.get(binding.bindingId);
    if (bindingNode === undefined) continue;
    for (const [index, definition] of binding.definitions.entries()) {
      const definitionNode = retainNode(context.state, context.file, {
        kind: "expression",
        roleKey: `definition:${binding.bindingId}:${String(index)}`,
        location: definition.location,
        label: definition.kind,
        functionNodeId: bindingNode.function_node_id,
      });
      addRelation(context.state, {
        source: definitionNode,
        target: bindingNode,
        relation: "defines",
        resolution: "resolved",
      });
    }
  }
  for (const [index, reference] of context.ir.references.entries()) {
    if (index % 64 === 0) yield;
    const expression = retainNode(context.state, context.file, {
      kind: "expression",
      roleKey: `reference:${String(index)}:${reference.role}:${reference.name}`,
      location: reference.location,
      label: reference.name,
      functionNodeId:
        context.callableOwnerAt(reference.location)?.node_id ?? null,
    });
    const binding =
      reference.bindingId === null
        ? undefined
        : context.bindingNodes.get(reference.bindingId);
    if (expression !== null) context.referenceNodes.push(expression);
    if (binding === undefined || expression === null) continue;
    if (reference.role === "read")
      addRelation(context.state, {
        source: binding,
        target: expression,
        relation: "reads",
        resolution: "resolved",
        evidence: inferredSemanticEvidenceAt(context.file, reference.location),
      });
    else
      addRelation(context.state, {
        source: expression,
        target: binding,
        relation: "writes",
        resolution: "resolved",
      });
  }
}

const projectCalls = (context: FileContext): void => {
  for (const call of context.ir.callSites) {
    const callNode = context.callSiteNodes.get(call.callSiteId);
    if (callNode === undefined) continue;
    for (const callableId of call.calleeCallableIds) {
      const callable = context.callableNodes.get(callableId);
      addRelation(context.state, {
        source: callNode,
        target: callable,
        relation: "calls",
        resolution: call.resolution === "exact" ? "resolved" : "candidate",
      });
    }
    for (const argument of call.arguments) {
      const argumentNode = createArgumentNode(
        context,
        callNode,
        call.callSiteId,
        argument,
      );
      if (argumentNode !== null)
        context.argumentNodes.set(
          `${call.callSiteId}\u0000${String(argument.index)}`,
          argumentNode,
        );
      const references = context.referenceNodesWithin(argument.location);
      for (const reference of references)
        addRelation(context.state, {
          source: reference,
          target: argumentNode,
          relation: "aliases",
          resolution:
            references.length === 1 &&
            rangesEqual(reference.identity.source_range, argument.location)
              ? "resolved"
              : "candidate",
        });
    }
  }
  for (const flow of context.ir.argumentFlows) {
    const argument = context.argumentNodes.get(
      `${flow.callSiteId}\u0000${String(flow.argumentIndex)}`,
    );
    const parameter = context.bindingNodes.get(flow.parameterBindingId);
    addRelation(context.state, {
      source: argument,
      target: parameter,
      relation: "argument-to-parameter",
      resolution: context.callResolutions.get(flow.callSiteId) ?? "candidate",
    });
  }
  for (const flow of context.ir.callReturnFlows)
    addRelation(context.state, {
      source: context.returnSiteNodes.get(flow.returnSiteId),
      target: context.callSiteNodes.get(flow.callSiteId),
      relation: "returns-to-call",
      resolution: context.callResolutions.get(flow.callSiteId) ?? "candidate",
    });
  for (const flow of context.ir.callResultFlows)
    addRelation(context.state, {
      source: context.callSiteNodes.get(flow.callSiteId),
      target: context.bindingNodes.get(flow.bindingId),
      relation: "aliases",
      resolution: context.callResolutions.get(flow.callSiteId) ?? "candidate",
    });
  projectSemanticReturnValues(context);
};

const createArgumentNode = (
  context: FileContext,
  callNode: JavaScriptSemanticGraphNode,
  callSiteId: string,
  argument: JavaScriptSemanticCallArgument,
): JavaScriptSemanticGraphNode | null =>
  retainNode(context.state, context.file, {
    kind: "expression",
    roleKey: `argument:${callSiteId}:${String(argument.index)}`,
    location: argument.location,
    label: argument.spread
      ? "spread argument"
      : `argument ${String(argument.index)}`,
    functionNodeId: callNode.function_node_id,
  });

/** Per-file projection passes, run in this order with a yield between each. */
const FILE_PROJECTION_PASSES: readonly ((
  context: FileContext,
) => Iterator<void, void> | void)[] = [
  projectSemanticValues,
  projectSemanticObjects,
  projectCalls,
  projectSemanticPromises,
  projectSemanticEvents,
  projectSemanticTimers,
  projectSemanticChildProcesses,
  projectSemanticConfiguration,
  projectSemanticRequests,
  projectSemanticBoundaries,
  projectSemanticResources,
  projectSemanticClosureCaptures,
  projectSemanticFrontiers,
];