Alternate extract-errors that scrapes artifacts

The build script outputs a special FIXME comment when it fails to minify
an error message. CI will detect these comments and fail the workflow.

The comments also include the expected error message. So I added an
alternate extract-errors that scrapes unminified messages from the
build artifacts and updates `codes.json`.

This is nice because it works on partial builds. And you can also run it
after the fact, instead of needing build all over again.

package.json

@@ -115,6 +115,7 @@
     "lint": "node ./scripts/tasks/eslint.js",
     "lint-build": "node ./scripts/rollup/validate/index.js",
     "extract-errors": "yarn build --type=dev --extract-errors",
+    "extract-errors2": "node scripts/error-codes/extract-errors2.js",
     "postinstall": "node node_modules/fbjs-scripts/node/check-dev-engines.js package.json && node ./scripts/flow/createFlowConfigs.js && node ./scripts/yarn/downloadReactIsForPrettyFormat.js",
     "debug-test": "yarn test --deprecated 'yarn test --debug'",
     "test": "node ./scripts/jest/jest-cli.js",

scripts/error-codes/__tests__/__snapshots__/transform-error-messages.js.snap

@@ -13,7 +13,7 @@ NotAnError();"
 exports[`error transform should output FIXME for errors that don't have a matching error code 1`] = `
 "/*! FIXME (minify-errors-in-prod): Unminified error message in production build!*/
 
-/*! Add to error code map: This is not a real error message.*/
+/*! <expected-error-format>\\"This is not a real error message.\\"</expected-error-format>*/
 Error('This is not a real error message.');"
 `;
 

scripts/error-codes/extract-errors2.js

@@ -0,0 +1,74 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const {execSync} = require('child_process');
+
+async function main() {
+  const originalJSON = JSON.parse(
+    fs.readFileSync(path.resolve(__dirname, '../error-codes/codes.json'))
+  );
+  const existingMessages = new Set();
+  const codes = Object.keys(originalJSON);
+  let nextCode = 0;
+  for (let i = 0; i < codes.length; i++) {
+    const codeStr = codes[i];
+    const message = originalJSON[codeStr];
+    const code = parseInt(codeStr, 10);
+    existingMessages.add(message);
+    if (code >= nextCode) {
+      nextCode = code + 1;
+    }
+  }
+
+  console.log('Searching `build` directory for unminified errors...\n');
+
+  let out;
+  try {
+    out = execSync(
+      "git --no-pager grep -n --untracked --no-exclude-standard '/*! <expected-error-format>' -- build"
+    ).toString();
+  } catch (e) {
+    if (e.status === 1 && e.stdout.toString() === '') {
+      // No unminified errors found.
+      return;
+    }
+    throw e;
+  }
+
+  let newJSON = null;
+  const regex = /\<expected-error-format\>"(.+?)"\<\/expected-error-format\>/g;
+  do {
+    const match = regex.exec(out);
+    if (match === null) {
+      break;
+    } else {
+      const message = match[1].trim();
+      if (existingMessages.has(message)) {
+        // This probably means you ran the script twice.
+        continue;
+      }
+      existingMessages.add(message);
+
+      // Add to json map
+      if (newJSON === null) {
+        newJSON = Object.assign({}, originalJSON);
+      }
+      console.log(`"${nextCode}": "${message}"`);
+      newJSON[nextCode] = message;
+      nextCode += 1;
+    }
+  } while (true);
+
+  if (newJSON) {
+    fs.writeFileSync(
+      path.resolve(__dirname, '../error-codes/codes.json'),
+      JSON.stringify(newJSON, null, 2)
+    );
+  }
+}
+
+main().catch(error => {
+  console.error(error);
+  process.exit(1);
+});

scripts/error-codes/transform-error-messages.js

@@ -57,7 +57,7 @@ module.exports = function(babel) {
       //
       // Outputs:
       //   /* FIXME (minify-errors-in-prod): Unminified error message in production build! */
-      //   /* Add to error code map: "A % message that contains %" */
+      //   /* <expected-error-format>"A % message that contains %"</expected-error-format> */
       //   if (!condition) {
       //     throw Error(`A ${adj} message that contains ${noun}`);
       //   }
@@ -83,7 +83,7 @@ module.exports = function(babel) {
 
       statementParent.addComment(
         'leading',
-        '! Add to error code map: ' + errorMsgLiteral
+        `! <expected-error-format>"${errorMsgLiteral}"</expected-error-format>`
       );
       statementParent.addComment(
         'leading',