Warn when a non-existent property of an unfinished module.exports
object is being accessed, as that very often indicates the presence
of a hard-to-detect and hard-to-debug problem.
This mechanism is only used if `module.exports` is still a
regular object at the point at which the second, circular `require()`
happens.
The downside is that, temporarily, `module.exports` will have a
prototype other than `Object.prototype`, and that there may
be valid uses of accessing non-existent properties of unfinished
`module.exports` objects.
Performance of circular require calls in general is not
noticeably impacted.
confidence improvement accuracy (*) (**) (***)
module/module-loader-circular.js n=10000 3.96 % ±5.12% ±6.82% ±8.89%
Example:
$ cat a.js
'use strict';
const b = require('./b.js');
exports.fn = () => {};
$ cat b.js
'use strict';
const a = require('./a.js');
a.fn();
$ node a.js
(node:1617) Warning: Accessing non-existent property 'fn' of module exports inside circular dependency
/tmp/b.js:4
a.fn();
^
TypeError: a.fn is not a function
at Object.<anonymous> (/tmp/b.js:4:3)
[...]
PR-URL: https://github.com/nodejs/node/pull/29935
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
A benchmark for module loading creates a temporary directory in the
benchmark directory. Re-use the test common module to put the tmp
directory in test instead. This was causing intermittent test failures
because run.js (invoked by benchmark tests, mulitple of which could be
running at once) throws if a subdirectory of benchmark disappears at
just the wrong time.
There are other possible solutions than repurposing the `test/common`
module but two arguments for doing it this way are:
* There is already another benchmark file that does this
(`http_server_for_chunky_client.js`) so the dependency already exists
in the benchmarks.
* This also eliminates a re-implementation of rimraf in the benchmark
code.
PR-URL: https://github.com/nodejs/node/pull/16144
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
In the hopes of soon having the benchmark code linted, this change
groups all the likely non-controversial lint-compliance changes such as
indentation, semi-colon usage, and single-vs.-double quotation marks.
Other lint rules may have subtle performance implications in the V8
currently shipped with Node.js. Those changes will require more careful
review and will be in a separate change.
PR-URL: https://github.com/nodejs/node/pull/5429
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: Brian White <mscdex@mscdex.net>
