Files
reverse-engineering-anything/src/domain/javascript/javascriptSemanticObjectReferences.test.ts
T

273 lines
9.1 KiB
TypeScript

import * as t from "@babel/types";
import { expect, it } from "vitest";
import { indexJavaScriptBindingsSteps } from "../../../tests/fixtures/javascriptSemanticIndex.js";
import {
semanticClassPropertyReferences,
semanticNativePrototypeChain,
semanticObjectPropertyReferences,
} from "./javascriptSemanticObjectReferences.js";
import { completeSemanticSteps } from "./javascriptSemanticTraversal.js";
import { parseJavaScriptSource } from "./javascriptSourceParser.js";
import { getterExpansionSource } from "../../../tests/fixtures/javascriptGetterExpansion.js";
const objectAndState = (source: string) => {
const parsed = parseJavaScriptSource(source, "object.js");
if (parsed === null) throw new Error("Expected a parsed fixture");
const declaration = parsed.program.body[0];
if (!t.isVariableDeclaration(declaration))
throw new Error("Expected a declaration");
const init = declaration.declarations[0]?.init;
if (!t.isObjectExpression(init)) throw new Error("Expected an object");
return {
object: init,
source,
state: completeSemanticSteps(indexJavaScriptBindingsSteps(parsed.program)),
};
};
const spelled = (
fixture: ReturnType<typeof objectAndState>,
key: string | number | null,
) =>
semanticObjectPropertyReferences(fixture.object, [key], fixture.state).map(
({ node, path }) => [
fixture.source.slice(node.start ?? 0, node.end ?? 0),
JSON.stringify(path),
],
);
it.each([
["{}", "then", ["Object"]],
["{then:null}", "then", []],
["{then}", "then", []],
["{...{then:null}}", "then", []],
["{...unknown}", "then", ["Object"]],
["{__proto__:null}", "then", []],
["{__proto__:{}}", "then", []],
["{__proto__:0}", "then", ["Object"]],
["{__proto__:unknown}", "then", ["Object"]],
['{["__proto__"]:null}', "then", ["Object"]],
["[]", "then", ["Array", "Object"]],
["[]", "length", []],
["[value]", "0", []],
["[,value]", "0", ["Array", "Object"]],
["[value,...unknown]", "0", []],
["[...unknown,value]", "0", ["Array", "Object"]],
] as const)(
"retains possible native prototype lookup for %s[%s]",
(value, key, expected) => {
const parsed = parseJavaScriptSource(`const o=${value};`, "prototype.mjs");
const declaration = parsed?.program.body[0];
if (!t.isVariableDeclaration(declaration))
throw new Error("Expected declaration");
const node = declaration.declarations[0]?.init;
if (!t.isObjectExpression(node) && !t.isArrayExpression(node))
throw new Error("Expected literal");
expect(semanticNativePrototypeChain(node, key)).toEqual(expected);
},
);
it("resolves exact keys with source-order overrides, spreads and accessors", () => {
const fixture = objectAndState(
`const o = { a: 1, ...base, b: 2, a: 3, [dynamic]: 4, __proto__: proto, ...{ b: 5 }, get c() { return 6; }, c: 7 };`,
);
// Later definite own fields exclude earlier computed-key alternatives.
expect(spelled(fixture, "a")).toEqual([
["{ b: 5 }", '["a"]'],
["4", "[]"],
["3", "[]"],
]);
expect(spelled(fixture, "b")).toEqual([["{ b: 5 }", '["b"]']]);
expect(spelled(fixture, "c")).toEqual([["7", "[]"]]);
expect(spelled(fixture, "missing")).toEqual([
["{ b: 5 }", '["missing"]'],
["proto", '["missing"]'],
["4", "[]"],
["base", '["missing"]'],
]);
// A wildcard keeps possible slots, excluding data replaced by a known spread.
expect(spelled(fixture, null)).toEqual([
["7", "[]"],
["{ b: 5 }", '[{"excludedKeys":["c"]}]'],
["proto", "[null]"],
["4", "[]"],
["3", "[]"],
["base", '[{"excludedKeys":["a","b","c"]}]'],
]);
// Numeric keys use the same exact spelling as string keys.
expect(
spelled(objectAndState(`const o = { 1: "one", 2: "two" };`), 1),
).toEqual([['"one"', "[]"]]);
});
it.each([1, "1"])(
"preserves inherited numeric property selection %j and own shadowing",
(key) => {
expect(
spelled(objectAndState("const o = { __proto__: prototype };"), key),
).toEqual([["prototype", JSON.stringify([String(key)])]]);
expect(
spelled(
objectAndState('const o = { __proto__: prototype, 1: "own" };'),
key,
),
).toEqual([['"own"', "[]"]]);
},
);
it.each([
[
"static",
"static method(){return 1;} method(){return 2;}",
"static method(){return 1;}",
],
[
"instance",
"static method(){return 1;} method(){return 2;}",
"method(){return 2;}",
],
[
"prototype",
"static method(){return 1;} method(){return 2;}",
"method(){return 2;}",
],
["static", "static method(){return 1;} static set method(value){}", null],
["static", "static method=child; static method(){return 1;}", "child"],
[
"static",
"static get method(){return child;} static method(){return 1;}",
"static method(){return 1;}",
],
[
"static",
"static method(){return 1;} static get method(){return child;}",
"child",
],
[
"static",
"static get method(){return child;} static method(){return 1;} static set method(value){}",
null,
],
] as const)(
"selects method-valued %s descriptors with runtime precedence: %s",
(kind, body, expected) => {
const source = `class Box { ${body} }`;
const parsed = parseJavaScriptSource(source, "methods.mjs");
if (parsed === null) throw new Error("Expected a parsed class");
const owner = parsed.program.body[0];
if (!t.isClassDeclaration(owner)) throw new Error("Expected a class");
const state = completeSemanticSteps(
indexJavaScriptBindingsSteps(parsed.program),
);
expect(
semanticClassPropertyReferences({ owner, kind }, ["method"], state).map(
({ node }) => source.slice(node.start ?? 0, node.end ?? 0),
),
).toEqual(expected === null ? [] : [expected]);
},
);
it.each(["method(){return 1;}", "...{method: child}"])(
"keeps an intervening object data definition between accessor pairs: %s",
(definition) => {
expect(
spelled(
objectAndState(
`const o = { get method(){return child;} , ${definition}, set method(value){} };`,
),
"method",
),
).toEqual([]);
},
);
it.each(["static", "instance"] as const)(
"retains inherited %s field ownership for enumerable copies",
(kind) => {
const source = `class Base { ${kind === "static" ? "static" : ""} method=child; } class Box extends Base {}`;
const parsed = parseJavaScriptSource(source, "fields.mjs");
if (parsed === null) throw new Error("Expected a parsed class");
const owner = parsed.program.body[1];
if (!t.isClassDeclaration(owner)) throw new Error("Expected derived class");
const state = completeSemanticSteps(
indexJavaScriptBindingsSteps(parsed.program),
);
const references = semanticClassPropertyReferences(
{ owner, kind, fieldsOnly: true },
["method"],
state,
);
expect(
references.map(({ node }) =>
source.slice(node.start ?? 0, node.end ?? 0),
),
).toEqual(["child"]);
expect(references[0]?.inherited).toBe(kind === "static" ? true : undefined);
},
);
it("preserves references through a small static getter permutation", () => {
const getters = Array.from(
{ length: 5 },
(_, index) =>
`static get field${index}() { return this[key].field${index}; }`,
).join("\n");
const source = `const key = getKey(); const shared = {}; class Request {
${getters}
static get state() { return shared; }
}`;
const parsed = parseJavaScriptSource(source, "getters.js");
if (parsed === null) throw new Error("Expected a parsed fixture");
const klass = parsed.program.body.find((node): node is t.ClassDeclaration =>
t.isClassDeclaration(node),
);
if (klass === undefined) throw new Error("Expected a class declaration");
const state = completeSemanticSteps(
indexJavaScriptBindingsSteps(parsed.program),
);
const references = semanticClassPropertyReferences(
{ owner: klass, kind: "static" },
["field0"],
state,
);
expect(
references.some(
({ node }) => source.slice(node.start ?? 0, node.end ?? 0) === "shared",
),
).toBe(true);
const distinctReferences = new Set(
references.map(({ node, path, escapes }) =>
JSON.stringify([node.start, node.end, path, escapes]),
),
);
expect(references).toHaveLength(distinctReferences.size);
});
it("widens a large static getter permutation to one escaped reference", () => {
const source = getterExpansionSource(30).replaceAll("get ", "static get ");
const parsed = parseJavaScriptSource(source, "getters.js");
if (parsed === null) throw new Error("Expected a parsed fixture");
const klass = parsed.program.body.find((node): node is t.ClassDeclaration =>
t.isClassDeclaration(node),
);
if (klass === undefined) throw new Error("Expected a class declaration");
const state = completeSemanticSteps(
indexJavaScriptBindingsSteps(parsed.program),
);
const references = semanticClassPropertyReferences(
{ owner: klass, kind: "static" },
["field0"],
state,
);
expect(references).toHaveLength(1);
expect(references[0]).toMatchObject({
node: { type: "Identifier", name: "shared" },
path: [],
escapes: true,
});
expect([...state.getterResourceLimits]).toEqual(["getter-expansion"]);
});