The Mocha (server-side) test bundle crashed at boot with 0 tests run because
yargs and its ESM dependencies are dragged into the Meteor test server bundle,
where Meteor 3 wraps every module in a CommonJS function and their native-ESM
constructs (import.meta, `const __dirname`, `const require = createRequire(...)`)
are illegal and crash the bundle before any test runs.
Two gaps remained in scripts/patch-yargs-dirname.cjs:
- The `const require = createRequire(...)` removal (and its trigger) only matched
the direct-call form. yargs-parser/build/lib/index.js uses the guarded ternary
`const require = createRequire ? createRequire(import.meta.url) : undefined;`,
which slipped through and crashed at boot with "Identifier 'require' has already
been declared". Generalized the match to line-wise `const require = ...createRequire...;`.
- The scan only walked node_modules/yargs, so yargs-parser (the actual offender)
was never patched. Broadened the scan to yargs and its ESM dependency packages.
Also register the three server test files that were present but missing from the
curated server/lib/tests/index.js (they never ran): the MimeBleed file-validation
bypass regression, the import/export privacy settings, and the impersonation report
query. Server suite now boots and runs (411 passing).
CHANGELOG Upcoming documents the bug and the two-stage debugging journey.
The yargs postinstall patch expanded import.meta.url -> require('url').pathToFileURL(...)
BEFORE removing the const require = createRequire(...) call. The paren-naive removal
regex createRequire([^)]*) then stopped at the first ) of the injected require('url'),
replacing only part of the statement and leaving a dangling
/* Meteor: use wrapper require */.pathToFileURL(__filename).href));
in yargs' esm.mjs. That is invalid JS (a leading .pathToFileURL after a comment), so
Meteor's reify parser threw 'Unexpected token (19:33)' when the test server bundle pulled
yargs in -- meteor test reported 0 tests, even though every repo source file was fine.
Fix: remove the createRequire call BEFORE expanding import.meta.url (so the injected
parens can't break the match), and add a repair rule + trigger so re-running the script
collapses the dangling leftover in already-corrupted node_modules/yargs files back to the
marker. Fresh and already-broken files both end valid.
The crash moved from yargs/lib/platform-shims/esm.mjs to yargs/build/lib/utils/
apply-extends.js (import.meta.resolve(config.extends)) — yargs' ESM build has more than
one file using import.meta. Rewrite the workaround to scan the whole node_modules/yargs
tree and rewrite every ESM-only construct (import.meta.url/.resolve/.dirname/.filename,
const require = createRequire(...), and yargs' own const __dirname) to the CommonJS
wrapper equivalents in one pass, so a new yargs file can't reintroduce the boot crash.
yargs is never executed at runtime here, so only valid CommonJS parsing matters.
Thanks to xet7.
Renaming only __dirname was not enough: yargs' esm.mjs also uses import.meta.url (invalid
in Meteor's CommonJS module wrapper -> 'Cannot use import.meta outside a module') and
redeclares require via createRequire(import.meta.url) (collides with the wrapper's
require). reify rewrites the file's import statements but not import.meta. Rewrite all
three to use the wrapper's __filename / __dirname / require, which yargs never actually
exercises here (it is only bundled, never called). Idempotent; also patches a file left
half-rewritten by the previous version of this script.
Thanks to xet7.
.meteorignore does not apply to node_modules under Meteor 3 / rspack (verified: the
rebuilt Mocha bundle still contained node_modules/yargs), so revert that no-op rule and
fix the actual crash instead.
Root cause (pre-existing, unrelated to app code): the whole yargs package gets pulled
into the server bundle as a transitive devDependency, and its ESM shim
node_modules/yargs/lib/platform-shims/esm.mjs declares a top-level
'const __dirname = fileURLToPath(import.meta.url)'. Meteor wraps that .mjs in a CommonJS
module function that already provides __dirname, so it collides —
'SyntaxError: Identifier __dirname has already been declared' — crashing the server
bundle at boot, which is why Mocha reported 0 tests.
Add scripts/patch-yargs-dirname.cjs, run from a package.json postinstall, which renames
yargs' local __dirname (and its .substring/.lastIndexOf uses) to __dirnameYargs so it can
no longer collide with the wrapper's. Idempotent and best-effort (never fails install);
yargs is not used at runtime here so the rename is inert for the app.
Thanks to xet7.
Lauri Ojansivu