Ionic cordova resources --splash and --icon error

Question

I´m getting this error on resources generator:
Error: end() has already been called, so it's too late to start piping

I´m stuck with this error. Shows up when I try to generate resources:

PS F:\Desenvolvimento\Ionic\Divas> ionic cordova resources ios -f
√ Collecting resource configuration and source images - done!
√ Filtering out image resources that do not need regeneration - done!
√ Uploading source images to prepare for transformations: 2 / 2 complete - done!
- Generating platform resources: 8 / 32 complete
C:\Users\Gustavo\AppData\Roaming\npm\node_modules\ionic\node_modules\superagent\lib\node\index.js:859
      throw Error("end() has already been called, so it's too late to start piping");
      ^

Error: end() has already been called, so it's too late to start piping
    at Response.response.pipe (C:\Users\Gustavo\AppData\Roaming\npm\node_modules\ionic\node_modules\superagent\lib\node\index.js:859:13)
    at Request.req.type.send.on.res (C:\Users\Gustavo\AppData\Roaming\npm\node_modules\ionic\lib\integrations\cordova\resources.js:166:25)
    at Request.emit (events.js:182:13)
    at Request._emitResponse (C:\Users\Gustavo\AppData\Roaming\npm\node_modules\ionic\node_modules\superagent\lib\node\index.js:862:8)
    at ClientRequest.req.once.res (C:\Users\Gustavo\AppData\Roaming\npm\node_modules\ionic\node_modules\superagent\lib\node\index.js:412:10)
    at Object.onceWrapper (events.js:273:13)
    at ClientRequest.emit (events.js:187:15)
    at HTTPParser.parserOnIncomingClient [as onIncoming] (_http_client.js:556:21)
    at HTTPParser.parserOnHeadersComplete (_http_common.js:109:17)
    at TLSSocket.socketOnData (_http_client.js:442:20)

My system:

Ionic:

   ionic (Ionic CLI)  : 4.7.1 (C:\Users\Gustavo\AppData\Roaming\npm\node_modules\ionic)
   Ionic Framework    : ionic-angular 3.9.2
   @ionic/app-scripts : 3.2.0

Cordova:

   cordova (Cordova CLI) : not installed
   Cordova Platforms     : android 6.3.0
   Cordova Plugins       : cordova-plugin-ionic-webview 1.1.1, (and 8 other plugins)

System:

   NodeJS : v10.15.0 (C:\Program Files\nodejs\node.exe)
   npm    : 6.5.0
   OS     : Windows 10

Answer 1

I was getting the exact same error. I noticed my icon.png (the one I created) was 1024x916 and it didn't like it. I resized it to be exactly 1024x1024 and now it works!!!

Answer 2

I got the same error on linux:

My new icon used alpha channel (my mistake) and i got this error. When i saw this thread, i understood this tool could be very sensible. My icon (old & new) was 512*512. My spash was 2300*2400. => Putting all image to the correct size had no effect. 'flattening' my image using gimp was the solution.

My conclusion : don't use alpha channel in your images