test: add unit test for the optional dependency patch (#277)

Co-authored-by: James Anderson <[email protected]>

Author: vicb

packages/cloudflare/src/cli/build/patches/ast/optional-deps.spec.ts

@@ -0,0 +1,101 @@
+import { describe, expect, it } from "vitest";
+
+import { optionalDepRule } from "./optional-deps.js";
+import { patchCode } from "./util.js";
+
+describe("optional dependecy", () => {
+  it('should wrap a top-level require("caniuse-lite") in a try-catch', () => {
+    const code = `t = require("caniuse-lite");`;
+    expect(patchCode(code, optionalDepRule)).toMatchInlineSnapshot(`
+      "try {
+        t = require("caniuse-lite");
+      } catch {
+        throw new Error('The optional dependency "caniuse-lite" is not installed');
+      };"
+    `);
+  });
+
+  it('should wrap a top-level require("caniuse-lite/data") in a try-catch', () => {
+    const code = `t = require("caniuse-lite/data");`;
+    expect(patchCode(code, optionalDepRule)).toMatchInlineSnapshot(
+      `
+      "try {
+        t = require("caniuse-lite/data");
+      } catch {
+        throw new Error('The optional dependency "caniuse-lite/data" is not installed');
+      };"
+    `
+    );
+  });
+
+  it('should wrap e.exports = require("caniuse-lite") in a try-catch', () => {
+    const code = 'e.exports = require("caniuse-lite");';
+    expect(patchCode(code, optionalDepRule)).toMatchInlineSnapshot(`
+      "try {
+        e.exports = require("caniuse-lite");
+      } catch {
+        throw new Error('The optional dependency "caniuse-lite" is not installed');
+      };"
+    `);
+  });
+
+  it('should wrap module.exports = require("caniuse-lite") in a try-catch', () => {
+    const code = 'module.exports = require("caniuse-lite");';
+    expect(patchCode(code, optionalDepRule)).toMatchInlineSnapshot(`
+      "try {
+        module.exports = require("caniuse-lite");
+      } catch {
+        throw new Error('The optional dependency "caniuse-lite" is not installed');
+      };"
+    `);
+  });
+
+  it('should wrap exports.foo = require("caniuse-lite") in a try-catch', () => {
+    const code = 'exports.foo = require("caniuse-lite");';
+    expect(patchCode(code, optionalDepRule)).toMatchInlineSnapshot(`
+      "try {
+        exports.foo = require("caniuse-lite");
+      } catch {
+        throw new Error('The optional dependency "caniuse-lite" is not installed');
+      };"
+    `);
+  });
+
+  it('should not wrap require("lodash") in a try-catch', () => {
+    const code = 't = require("lodash");';
+    expect(patchCode(code, optionalDepRule)).toMatchInlineSnapshot(`"t = require("lodash");"`);
+  });
+
+  it('should not wrap require("other-module") if it does not match caniuse-lite regex', () => {
+    const code = 't = require("other-module");';
+    expect(patchCode(code, optionalDepRule)).toMatchInlineSnapshot(`"t = require("other-module");"`);
+  });
+
+  it("should not wrap a require() call already inside a try-catch", () => {
+    const code = `
+try {
+  const t = require("caniuse-lite");
+} catch {}
+`;
+    expect(patchCode(code, optionalDepRule)).toMatchInlineSnapshot(`
+      "try {
+        const t = require("caniuse-lite");
+      } catch {}
+      "
+    `);
+  });
+
+  it("should handle require with subpath and not wrap if already in try-catch", () => {
+    const code = `
+try {
+  const t = require("caniuse-lite/path");
+} catch {}
+`;
+    expect(patchCode(code, optionalDepRule)).toMatchInlineSnapshot(`
+      "try {
+        const t = require("caniuse-lite/path");
+      } catch {}
+      "
+    `);
+  });
+});

packages/cloudflare/src/cli/build/patches/ast/optional-deps.ts

@@ -1,21 +1,15 @@
 import { type SgNode } from "@ast-grep/napi";
 
-import { applyRule } from "./util.js";
+import { getRuleEdits } from "./util.js";
 
 /**
  * Handle optional dependencies.
  *
- * A top level `require(dep)` would throw when the dep is not installed.
+ * A top level `require(optionalDep)` would throw when the dep is not installed.
  *
- * So we wrap any of
- * - `t = require("dep")`
- * - `t = require("dep/sub/path")`
- * - `t = require("dep/sub/path/" + var)`
- * - `e.exports = require("dep")`
- *
- * in a try/catch (only if not already).
+ * So we wrap `require(optionalDep)` in a try/catch (if not already present).
  */
-const rule = `
+export const optionalDepRule = `
 rule:
   pattern: $$$LHS = require($$$REQ)
   has:
@@ -37,5 +31,5 @@ fix: |-
 `;
 
 export function patchOptionalDependencies(root: SgNode) {
-  return applyRule(rule, root);
+  return getRuleEdits(optionalDepRule, root);
 }

packages/cloudflare/src/cli/build/patches/ast/util.spec.ts

@@ -0,0 +1,65 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { patchCode } from "./util.js";
+
+describe("patchCode", () => {
+  afterEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("should throw an error if rule has a transform", () => {
+    expect(() =>
+      patchCode(`console.log("hi")`, { rule: { pattern: "console.log($MSG)" }, transform: "not supported" })
+    ).toThrow(/not supported/);
+  });
+
+  it("should throw an error if rule has no fix", () => {
+    expect(() => patchCode(`console.log("hi")`, { rule: { pattern: "console.log($MSG)" } })).toThrow(
+      /no fix/
+    );
+  });
+
+  it("should accept yaml rules", () => {
+    const yamlRule = `
+rule:
+  pattern: a
+fix: b
+`;
+
+    expect(patchCode(`a`, yamlRule)).toEqual("b");
+  });
+
+  it("should apply fix to a single match when once is true", () => {
+    expect(patchCode(`a+a`, { rule: { pattern: "a" }, fix: "b" }, { once: true })).toEqual("b+a");
+  });
+
+  it("should apply fix to all matches when once is false (default)", () => {
+    expect(patchCode(`a+a`, { rule: { pattern: "a" }, fix: "b" })).toEqual("b+b");
+    expect(patchCode(`a+a`, { rule: { pattern: "a" }, fix: "b" }, { once: false })).toEqual("b+b");
+  });
+
+  it("should handle no matches", () => {
+    expect(patchCode(`a`, { rule: { pattern: "b" }, fix: "c" })).toEqual("a");
+  });
+
+  it("should replace $PLACEHOLDER with match text", () => {
+    expect(
+      patchCode(`console.log(message)`, { rule: { pattern: "console.log($MSG)" }, fix: "$MSG" })
+    ).toEqual("message");
+  });
+
+  it("should handle $PLACEHODLERS that are not found in matches", () => {
+    expect(
+      patchCode(`console.log(message)`, { rule: { pattern: "console.log($MSG)" }, fix: "$WHAT$$$WHAT" })
+    ).toEqual("$WHAT");
+  });
+
+  it("should replace $$$PLACEHOLDER with match text", () => {
+    expect(
+      patchCode(`console.log("hello" + world, "!")`, {
+        rule: { pattern: "console.log($$$ARGS)" },
+        fix: "$$$ARGS",
+      })
+    ).toEqual(`"hello" + world,"!"`);
+  });
+});

packages/cloudflare/src/cli/build/patches/ast/util.ts

@@ -1,30 +1,36 @@
-import { type Edit, type NapiConfig, type SgNode } from "@ast-grep/napi";
+import { type Edit, Lang, type NapiConfig, parse, type SgNode } from "@ast-grep/napi";
 import yaml from "yaml";
 
+/**
+ * fix has the same meaning as in yaml rules
+ * see https://ast-grep.github.io/guide/rewrite-code.html#using-fix-in-yaml-rule
+ */
+export type RuleConfig = NapiConfig & { fix?: string };
+
 /**
  * Returns the `Edit`s for an ast-grep rule in yaml format
  *
  * The rule must have a `fix` to rewrite the matched node.
  *
  * Tip: use https://ast-grep.github.io/playground.html to create rules.
  *
- * @param yamlRule The rule in yaml format
+ * @param rule The rule. Either a yaml string or an instance of `RuleConfig`
  * @param root The root node
  * @param once only apply once
  * @returns A list of edits.
  */
-export function applyRule(yamlRule: string, root: SgNode, { once = false } = {}) {
-  const rule: NapiConfig & { fix?: string } = yaml.parse(yamlRule);
-  if (rule.transform) {
+export function getRuleEdits(rule: string | RuleConfig, root: SgNode, { once = false } = {}) {
+  const ruleConfig: RuleConfig = typeof rule === "string" ? yaml.parse(rule) : rule;
+  if (ruleConfig.transform) {
     throw new Error("transform is not supported");
   }
-  if (!rule.fix) {
+  if (!ruleConfig.fix) {
     throw new Error("no fix to apply");
   }
 
-  const fix = rule.fix;
+  const fix = ruleConfig.fix;
 
-  const matches = once ? [root.find(rule)].filter((m) => m !== null) : root.findAll(rule);
+  const matches = once ? [root.find(ruleConfig)].filter((m) => m !== null) : root.findAll(ruleConfig);
 
   const edits: Edit[] = [];
 
@@ -46,3 +52,25 @@ export function applyRule(yamlRule: string, root: SgNode, { once = false } = {})
 
   return edits;
 }
+
+/**
+ * Patches the code from by applying the rule.
+ *
+ * This function is mainly for on off edits and tests,
+ * use `getRuleEdits` to apply multiple rules.
+ *
+ * @param code The source code
+ * @param rule The astgrep rule (yaml or NapiConfig)
+ * @param lang The language used by the source code
+ * @param lang Whether to apply the rule only once
+ * @returns The patched code
+ */
+export function patchCode(
+  code: string,
+  rule: string | RuleConfig,
+  { lang = Lang.TypeScript, once = false } = {}
+): string {
+  const node = parse(lang, code).root();
+  const edits = getRuleEdits(rule, node, { once });
+  return node.commitEdits(edits);
+}