React-native: [Getting Started] Error: ignoring return value of function declared with warn_unused_result attribute

[andresn]

Hi there, I'm snagged after a fresh install today:

$ react-native init AwesomeProject
$ react-native run-ios

Full log:
https://gist.github.com/andresn/1f35d718da9fc57542bb399460f2efd0#file-gistfile1-txt-L109

[email protected]
[email protected]
XCode Beta 8.0
Mac OS X El Capitan v.10.11.5

I think this is specific to having Xcode-beta 8.0 installed, because running the app through beta-7.3 does work.

[liweiz]

I had similar experience today. But it was on macOS beta. Build failed on both XCode 7.3.1 (7D1014) and 8.0 beta 2 (8S162m). I did try $ react-native run-ios but got error:

ERROR ENOENT: no such file or directory, lstat '/AwesomeProject/ios/build/ModuleCache/3F1D94PC0NUP2/AVFoundation-1M2ASOEW37WIZ.pcm-53d428b3'
{"errno":-2,"code":"ENOENT","syscall":"lstat","path":"/AwesomeProject/ios/build/ModuleCache/3F1D94PC0NUP2/AVFoundation-1M2ASOEW37WIZ.pcm-53d428b3"}
Error: ENOENT: no such file or directory, lstat '/AwesomeProject/ios/build/ModuleCache/3F1D94PC0NUP2/AVFoundation-1M2ASOEW37WIZ.pcm-53d428b3'
at Error (native)

macOS: 10.12 Beta (16A239j)
react-native-cli: 1.0.0
react-native: 0.29.0

Same two errors on both versions of XCode under Semantic Issue, when I tried build with XCode:

• /AwesomeProject/node_modules/react-native/Libraries/WebSocket/RCTSRWebSocket.m:494:3: Ignoring return value of function declared with warn_unused_result attribute
• /AwesomeProject/node_modules/react-native/Libraries/WebSocket/RCTSRWebSocket.m:1334:5: Ignoring return value of function declared with warn_unused_result attribute

Edit: Sorry, I forgot to mention that I was not able to install watchman.

[samtgarson]

+1 on this, getting almost exactly the same output as OP 😭

Could be related to https://github.com/facebook/react-native/issues/8108?

[cpruijsen]

I'm also facing this error :(

[crsanthony]

same :(

[huangkaiw3n]

I'm running into this issue as well. I'm on Xcode Version 8.0 beta 2. And OS X 10.11.5. I've got almost the same log too

[jlietart]

Same issue here :(

[adeolafadeyibi]

Same issue here:(

[zhaop4133]

Same issue here:(

[isramartinez]

Same issue here on Xcode version 8.0 beta 3

[adeolafadeyibi]

I uninstalled Xcode version 8.0 beta 3 and installed 7.3 and now everything works fine.

[TimBroddin]

Just doubleclick on the RCTWebSocket project in your navigator and remove the flags under _build settings_ > _custom compiler flags_

Your project should compile just fine now!

[adnsio]

@TimBroddin Thank you!!

[jdmarshall]

Having the same issue, but on XCode 7.2.1

I think the fact that upgrading XCode fixes this for some people has more to do with temporary files being retained somewhere and the installer deletes them.

What is the -proper- way to clear a working directory and rerun a build with react-native? I'm having problems with rebuilding and having components that have been deleted or renamed still causing errors, which means that some part of the build is not removing intermediate results between builds.

[danawhite]

Thanks for this!!

[javache]

Fixed by https://github.com/facebook/react-native/commit/2f788524112d59f62a295e7f4b0c1cfa0f6203fe

[sirgalleto]

How to upgrade to this version o this code in a "old" project @javache?

[javache]

We don't release patches for old releases, but you can apply these changes yourself.

[sirgalleto]

Oh thanks. I'll try

[tristanbbq]

Thanks @TimBroddin - it worked for me too!

[jmitch0901]

@TimBroddin your the man!

[dwilt]

I feel so embarrassed to be posting this. I can't figure out how to delete those flags. I tried hitting the delete key, right clicking on them, checking the file menu, but can't find anything. Someone please put me out of my misery.

[dwilt]

Oh, I figured it out. It was the values inside of those menus. Not the items themselves.

[raysmithdev]

@TimBroddin + 1

[jiangqqlmj]

thank you,this is fine~

[yongqianvip]

thank you @TimBroddin

[gviligvili]

@TimBroddin Thank you so much.

[beast]

👍

[pppluto]

:+1:

[digitalcatnip]

If we upgrade our React Native version after applying the above fix to remove the flags, will the upgrade restore the new patch for 0.34 properly?

[jariwalabhavesh]

Thank you @TimBroddin

[CoderStav]

@TimBroddin That did the trick, thanks.

[nicmar]

If you're like me, and trying to get FirebaseReactNativeSample to work, you need to go to FirebaseReactNativeSample > Libraries > RCTWebsocket.xcodeproj and then search in the right side for "custom", and you'll find it. It worked for me after doing that :)

[wallacyyy]

@TimBroddin you are such a hero.

[robbiemoore]

I updated to Sierra, initialised a new rn project, removed the flags and I still get the error: Application AppName has not been registered. This is either due to a require() error during initialisation or failure to call AppRegistry.registerComponent. Any thoughts?

[edin-m]

@frostfat +1 (I tried RCTWebRTCDemo on macOS Sierra).
I got around it by putting (void) in front of function call on error line.

[Hamiltontx]

TimBroddin tks a lot, save me time.

[seanfuture]

@edin-m's solution of (void) in front of line temporarily worked for us on Sierra .. TY

[noprom]

Also faced with this problem, but my settings here is empty:

Here is my environment:

react-native-cli: 1.0.0
react-native: 0.32.0
xcode:Version 8.0 (8A218a)
mac:10.12 (16A323)

Thanks in advance.

[breadadams]

@noprom it looks like you're searching in your main project. If you click RCTWebSocket in the sidebar, and then search in Build Settings, you should see it.

[xugy0926]

@TimBroddin i love u

[jtanori]

@TimBroddin you are the MVP here.

[heliosPortal]

@TimBroddin, Bless your children, give them names...

[dhwrwmgwra]

@TimBroddin You rock

[qxqxqxqx]

@dwilt I do take a while to figure it out,hahaha

[IWantToLearnCoding]

@TimBroddin God bless you children...