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[10/11] refactor(deslop): share cycle detection traversal #1485

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[10/11] refactor(deslop): share cycle detection traversal #1485

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4 changes: 0 additions & 4 deletions packages/deslop-js/src/constants.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -377,12 +377,8 @@ export const INLINE_TYPE_PREVIEW_KEYS = 4;

export const SIMPLIFIABLE_EXPRESSION_MEMBER_ACCESS_DEPTH = 6;

export const ANALYSIS_ERROR_PRINT_LIMIT = 20;

export const DUPLICATE_INLINE_TYPE_HIGH_MEMBER_COUNT = 5;

export const SEMANTIC_PROGRAM_BUDGET_MS = 30_000;

export const SEMANTIC_TRACE_MAX_ENTRIES = 5;

export const DEFAULT_DUPLICATE_BLOCK_MIN_TOKENS = 50;
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106 changes: 4 additions & 102 deletions packages/deslop-js/src/report/cycles.ts
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Expand Up @@ -4,21 +4,7 @@ import {
MAX_TOTAL_CYCLES,
MAX_SCC_SIZE_FOR_ENUMERATION,
} from "../constants.js";

const UNDEFINED_INDEX = -1;

interface TarjanState {
indexCounter: number;
indices: number[];
lowlinks: number[];
onStack: boolean[];
stack: number[];
}

interface DfsFrame {
node: number;
successorPosition: number;
}
import { findStronglyConnectedComponents } from "../utils/find-strongly-connected-components.js";

// A value-form import (`import { Props } from "./barrel"`) whose every
// symbol resolves to a type-only export (interface / type alias) in the
Expand Down Expand Up @@ -100,92 +86,6 @@ const cycleHasModuleInitAccess = (cycle: number[], initAccessEdges: Set<string>)
return false;
};

const findStronglyConnectedComponents = (adjacencyList: number[][]): number[][] => {
const nodeCount = adjacencyList.length;
if (nodeCount === 0) {
return [];
}

const state: TarjanState = {
indexCounter: 0,
indices: Array(nodeCount).fill(UNDEFINED_INDEX),
lowlinks: Array(nodeCount).fill(0),
onStack: Array(nodeCount).fill(false),
stack: [],
};

const components: number[][] = [];
const dfsStack: DfsFrame[] = [];

for (let startNode = 0; startNode < nodeCount; startNode++) {
if (state.indices[startNode] !== UNDEFINED_INDEX) {
continue;
}

state.indices[startNode] = state.indexCounter;
state.lowlinks[startNode] = state.indexCounter;
state.indexCounter++;
state.onStack[startNode] = true;
state.stack.push(startNode);

dfsStack.push({ node: startNode, successorPosition: 0 });

while (dfsStack.length > 0) {
const frame = dfsStack[dfsStack.length - 1];
const successors = adjacencyList[frame.node];

if (frame.successorPosition < successors.length) {
const successor = successors[frame.successorPosition];
frame.successorPosition++;

if (state.indices[successor] === UNDEFINED_INDEX) {
state.indices[successor] = state.indexCounter;
state.lowlinks[successor] = state.indexCounter;
state.indexCounter++;
state.onStack[successor] = true;
state.stack.push(successor);

dfsStack.push({ node: successor, successorPosition: 0 });
} else if (state.onStack[successor]) {
state.lowlinks[frame.node] = Math.min(
state.lowlinks[frame.node],
state.indices[successor],
);
}
} else {
const currentNode = frame.node;
const currentLowlink = state.lowlinks[currentNode];
const currentIndex = state.indices[currentNode];
dfsStack.pop();

if (dfsStack.length > 0) {
const parentFrame = dfsStack[dfsStack.length - 1];
state.lowlinks[parentFrame.node] = Math.min(
state.lowlinks[parentFrame.node],
currentLowlink,
);
}

if (currentLowlink === currentIndex) {
const component: number[] = [];
let poppedNode: number;
do {
poppedNode = state.stack.pop()!;
state.onStack[poppedNode] = false;
component.push(poppedNode);
} while (poppedNode !== currentNode);

if (component.length >= 2) {
components.push(component);
}
}
}
}
}

return components;
};

const canonicalizeCycle = (cycle: number[], graph: DependencyGraph): number[] => {
if (cycle.length === 0) {
return [];
Expand Down Expand Up @@ -270,7 +170,9 @@ const enumerateElementaryCycles = (
export const detectCycles = (graph: DependencyGraph): CircularDependency[] => {
const adjacencyList = buildAdjacencyList(graph);
const initAccessEdges = buildModuleInitAccessEdgeSet(graph);
const components = findStronglyConnectedComponents(adjacencyList);
const components = findStronglyConnectedComponents(adjacencyList).filter(
(component) => component.length >= 2,
);
const allCycles: number[][] = [];
const seenKeys = new Set<string>();

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74 changes: 2 additions & 72 deletions packages/deslop-js/src/report/re-export-cycles.ts
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
import type { DependencyGraph, ReExportCycle } from "../types.js";
import { findStronglyConnectedComponents } from "../utils/find-strongly-connected-components.js";

/**
* Reports cycles in the subgraph of `isReExportEdge` edges only. These are
Expand All @@ -22,7 +23,7 @@ export const detectReExportCycles = (graph: DependencyGraph): ReExportCycle[] =>
adjacency[edge.source].push(edge.target);
}

const sccComponents = computeStronglyConnectedComponents(adjacency);
const sccComponents = findStronglyConnectedComponents(adjacency);
const findings: ReExportCycle[] = [];

for (const component of sccComponents) {
Expand Down Expand Up @@ -56,74 +57,3 @@ export const detectReExportCycles = (graph: DependencyGraph): ReExportCycle[] =>
);
return findings;
};

/**
* Iterative Tarjan's SCC. Singleton components are returned too so the
* caller can distinguish a real self-loop from a node with no edges.
*/
const computeStronglyConnectedComponents = (adjacency: number[][]): number[][] => {
const nodeCount = adjacency.length;
if (nodeCount === 0) return [];

const indices: number[] = new Array(nodeCount).fill(-1);
const lowLinks: number[] = new Array(nodeCount).fill(0);
const onStack: boolean[] = new Array(nodeCount).fill(false);
const tarjanStack: number[] = [];
const components: number[][] = [];
let nextIndex = 0;

for (let startNode = 0; startNode < nodeCount; startNode++) {
if (indices[startNode] !== -1) continue;

const dfsStack: { node: number; successorPosition: number }[] = [
{ node: startNode, successorPosition: 0 },
];
indices[startNode] = nextIndex;
lowLinks[startNode] = nextIndex;
nextIndex++;
onStack[startNode] = true;
tarjanStack.push(startNode);

while (dfsStack.length > 0) {
const frame = dfsStack[dfsStack.length - 1];
const successors = adjacency[frame.node];

if (frame.successorPosition < successors.length) {
const successorNode = successors[frame.successorPosition];
frame.successorPosition++;
if (indices[successorNode] === -1) {
indices[successorNode] = nextIndex;
lowLinks[successorNode] = nextIndex;
nextIndex++;
onStack[successorNode] = true;
tarjanStack.push(successorNode);
dfsStack.push({ node: successorNode, successorPosition: 0 });
} else if (onStack[successorNode]) {
if (indices[successorNode] < lowLinks[frame.node]) {
lowLinks[frame.node] = indices[successorNode];
}
}
} else {
if (lowLinks[frame.node] === indices[frame.node]) {
const component: number[] = [];
let popped: number;
do {
popped = tarjanStack.pop()!;
onStack[popped] = false;
component.push(popped);
} while (popped !== frame.node);
components.push(component);
}
dfsStack.pop();
if (dfsStack.length > 0) {
const parent = dfsStack[dfsStack.length - 1];
if (lowLinks[frame.node] < lowLinks[parent.node]) {
lowLinks[parent.node] = lowLinks[frame.node];
}
}
}
}
}

return components;
};
15 changes: 0 additions & 15 deletions packages/deslop-js/src/utils/oxc-ast-node.ts
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Expand Up @@ -13,21 +13,6 @@ export const getNodeStringField = (node: OxcAstNode, key: string): string | unde
return typeof value === "string" ? value : undefined;
};

export const getNodeChild = (node: OxcAstNode, key: string): OxcAstNode | undefined => {
const value = node[key];
return isOxcAstNode(value) ? value : undefined;
};

export const getNodeChildArray = (node: OxcAstNode, key: string): OxcAstNode[] => {
const value = node[key];
if (!Array.isArray(value)) return [];
const children: OxcAstNode[] = [];
for (const candidate of value) {
if (isOxcAstNode(candidate)) children.push(candidate);
}
return children;
};

export const getIdentifierName = (node: unknown): string | undefined => {
if (!isOxcAstNode(node)) return undefined;
if (node.type !== "Identifier") return undefined;
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