test: fix flaky test-fs-watchfile on macOS#13252
Uh oh!
There was an error while loading. Please reload this page.
Conversation
On macOS, a watcher created with fs.watch() does not necessarily start receiving events immediately. So it can miss a change by fs.writefile() if it comes very soon after the watcher is created. Fix test flakiness caused by this by using `setInterval()` to repeat the write action. Fixes: nodejs#13248
Trott added fs 
Trott commented May 27, 2017
Stress tests are being run with Stress test this PR (should succeed): https://ci.nodejs.org/job/node-stress-single-test/nodes=osx1010/1238/console Stress test master (should fail): https://ci.nodejs.org/job/node-stress-single-test/nodes=osx1010/1239/console (404 right now, but will appear when a host becomes available to run the test) |
Trott commented May 27, 2017
Trott commented May 27, 2017
Stress tests came back as expected: master with failures, this PR all green. |
| fs.writeFile(`${dir}/foo.txt`,'foo',common.mustCall(function(err){ | ||
| if(err)assert.fail(err); | ||
| })); | ||
| },1); |
There was a problem hiding this comment.
[question] is 1 safe? does it not cause a busy-wait-ish situation?
There was a problem hiding this comment.
maybe change to try{fs.writeFileSych ...?
There was a problem hiding this comment.
is
1safe?
It won't block the event loop or anything like that, if that's what you mean. The way intervals work, the next one only gets added to the queue after the first one finishes, and gets added to execute in the next tick of the event loop at the earliest.
There was a problem hiding this comment.
I figured it will not block the loop, but maybe stress the I/O. Although obviously the process shouldn't be doing anything else at this point.
I agree it's a least arbitrary value you could put here, so guess it could be read a sort of nextTickInterval idiom?
refack commented May 29, 2017
On macOS, a watcher created with fs.watch() does not necessarily start receiving events immediately. So it can miss a change by fs.writefile() if it comes very soon after the watcher is created. Fix test flakiness caused by this by using `setInterval()` to repeat the write action. PR-URL: nodejs#13252Fixes: nodejs#13248 Reviewed-By: Refael Ackermann <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Benjamin Gruenbaum <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Michael Dawson <[email protected]> Reviewed-By: James M Snell <[email protected]>
Trott commented May 30, 2017
Landed in 3b12a8d |
On macOS, a watcher created with fs.watch() does not necessarily start receiving events immediately. So it can miss a change by fs.writefile() if it comes very soon after the watcher is created. Fix test flakiness caused by this by using `setInterval()` to repeat the write action. PR-URL: #13252Fixes: #13248 Reviewed-By: Refael Ackermann <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Benjamin Gruenbaum <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Michael Dawson <[email protected]> Reviewed-By: James M Snell <[email protected]>
MylesBorins commented Jul 17, 2017
This does not land cleanly in LTS. Please feel free to manually backport. Please also feel free to replace do-not-land if it is being backported |
8 participants
On macOS, a watcher created with fs.watch() does not necessarily
start receiving events immediately. So it can miss a change by
fs.writefile() if it comes very soon after the watcher is created. Fix
test flakiness caused by this by using
setInterval()to repeat thewrite action.
Fixes: #13248
Checklist
make -j4 test(UNIX), orvcbuild test(Windows) passesAffected core subsystem(s)
test fs