AWS Amplify deployments failing - node.js

Question

I'm trying to update my AWS Amplify app and I get this error, I have no idea what's wrong, everything works just fine locally. I've been trying to scan this log to see if I can understand anything from it but I cannot find what's wrong. It successfully builds the backend and fails when after the front-end prebuild. I tried redeploying previous successful deployments, but they all fail as well, which confused me even more. Here are the Logs:
`
2022-11-17T22:49:16.082Z [INFO]: ## Starting Frontend Build
# Starting phase: preBuild
2022-11-17T22:49:16.082Z [INFO]: # Executing command: npm ci
2022-11-17T22:49:20.209Z [WARNING]: npm
2022-11-17T22:49:20.211Z [WARNING]: WARN ERESOLVE overriding peer dependency
npm WARN While resolving: #material-ui/core#3.9.3
npm WARN Found: react#17.0.2
npm WARN node_modules/react
npm WARN react#"^17.0.2" from the root project
npm WARN 57 more (#coreui/icons-react, #coreui/react, ...)
npm WARN
npm WARN Could not resolve dependency:
npm WARN peer react#"^16.3.0" from #material-ui/core#3.9.3
npm WARN node_modules/#material-ui/core
npm WARN peer #material-ui/core#"^3.2.0" from material-ui-pickers#2.2.4
npm WARN node_modules/material-ui-pickers
npm WARN 1 more (mdbreact)
npm WARN
npm WARN Conflicting peer dependency: react#16.14.0
npm WARN node_modules/react
npm WARN peer react#"^16.3.0" from #material-ui/core#3.9.3
npm WARN node_modules/#material-ui/core
npm WARN peer #material-ui/core#"^3.2.0" from material-ui-pickers#2.2.4
npm WARN node_modules/material-ui-pickers
npm WARN 1 more (mdbreact)
2022-11-17T22:49:20.218Z [WARNING]: npm WARN
2022-11-17T22:49:20.218Z [WARNING]: ERESOLVE overriding peer dependency
npm WARN While resolving: #material-ui/core#3.9.3
npm WARN Found: react-dom#17.0.2
npm WARN node_modules/react-dom
npm WARN react-dom#"^17.0.2" from the root project
npm WARN 21 more (#coreui/react, #hookform/error-message, ...)
npm WARN
npm WARN Could not resolve dependency:
npm WARN peer react-dom#"^16.3.0" from #material-ui/core#3.9.3
npm WARN node_modules/#material-ui/core
npm WARN peer #material-ui/core#"^3.2.0" from material-ui-pickers#2.2.4
npm WARN node_modules/material-ui-pickers
npm WARN 1 more (mdbreact)
npm WARN
npm WARN Conflicting peer dependency: react-dom#16.14.0
npm WARN node_modules/react-dom
npm WARN peer react-dom#"^16.3.0" from #material-ui/core#3.9.3
npm WARN node_modules/#material-ui/core
npm WARN peer #material-ui/core#"^3.2.0" from material-ui-pickers#2.2.4
npm WARN node_modules/material-ui-pickers
npm WARN 1 more (mdbreact)
2022-11-17T22:49:20.224Z [WARNING]: npm WARN ERESOLVE overriding peer dependency
2022-11-17T22:49:20.225Z [WARNING]: npm WARN While resolving: #material-ui/system#3.0.0-alpha.2
npm WARN Found: react#17.0.2
npm WARN node_modules/react
npm WARN react#"^17.0.2" from the root project
npm WARN 57 more (#coreui/icons-react, #coreui/react, ...)
npm WARN
npm WARN Could not resolve dependency:
npm WARN peer react#"^16.3.0" from #material-ui/system#3.0.0-alpha.2
npm WARN node_modules/#material-ui/system
npm WARN #material-ui/system#"^3.0.0-alpha.0" from #material-ui/core#3.9.3
npm WARN node_modules/#material-ui/core
npm WARN
npm WARN Conflicting peer dependency: react#16.14.0
npm WARN node_modules/react
npm WARN peer react#"^16.3.0" from #material-ui/system#3.0.0-alpha.2
npm WARN node_modules/#material-ui/system
2022-11-17T22:49:20.225Z [WARNING]: npm WARN #material-ui/system#"^3.0.0-alpha.0" from #material-ui/core#3.9.3
npm WARN node_modules/#material-ui/core
2022-11-17T22:49:20.229Z [WARNING]: npm WARN ERESOLVE overriding peer dependency
npm WARN While resolving: #material-ui/system#3.0.0-alpha.2
npm WARN Found: react-dom#17.0.2
2022-11-17T22:49:20.229Z [WARNING]: npm WARN node_modules/react-dom
npm WARN react-dom#"^17.0.2" from the root project
npm WARN 21 more (#coreui/react, #hookform/error-message, ...)
npm WARN
npm WARN Could not resolve dependency:
npm WARN peer react-dom#"^16.3.0" from #material-ui/system#3.0.0-alpha.2
npm WARN node_modules/#material-ui/system
npm WARN #material-ui/system#"^3.0.0-alpha.0" from #material-ui/core#3.9.3
npm WARN node_modules/#material-ui/core
npm WARN
npm WARN Conflicting peer dependency: react-dom#16.14.0
npm WARN node_modules/react-dom
npm WARN peer react-dom#"^16.3.0" from #material-ui/system#3.0.0-alpha.2
npm WARN node_modules/#material-ui/system
npm WARN #material-ui/system#"^3.0.0-alpha.0" from #material-ui/core#3.9.3
npm
2022-11-17T22:49:20.229Z [WARNING]: WARN node_modules/#material-ui/core
2022-11-17T22:49:20.235Z [WARNING]: npm WARN
2022-11-17T22:49:20.235Z [WARNING]: ERESOLVE overriding peer dependency
npm WARN While resolving: #material-ui/utils#3.0.0-alpha.3
npm WARN Found: react#17.0.2
npm WARN node_modules/react
npm WARN react#"^17.0.2" from the root project
npm WARN 57 more (#coreui/icons-react, #coreui/react, ...)
npm WARN
npm WARN Could not resolve dependency:
npm WARN peer react#"^16.3.0" from #material-ui/utils#3.0.0-alpha.3
npm WARN node_modules/#material-ui/utils
npm WARN #material-ui/utils#"^3.0.0-alpha.2" from #material-ui/core#3.9.3
npm WARN node_modules/#material-ui/core
npm
2022-11-17T22:49:20.235Z [WARNING]: WARN
npm WARN Conflicting peer dependency: react#16.14.0
npm WARN node_modules/react
npm WARN peer react#"^16.3.0" from #material-ui/utils#3.0.0-alpha.3
npm WARN node_modules/#material-ui/utils
npm WARN #material-ui/utils#"^3.0.0-alpha.2" from #material-ui/core#3.9.3
npm WARN node_modules/#material-ui/core
2022-11-17T22:49:20.240Z [WARNING]: npm WARN ERESOLVE
2022-11-17T22:49:20.240Z [WARNING]: overriding peer dependency
npm WARN While resolving: #material-ui/utils#3.0.0-alpha.3
npm WARN Found: react-dom#17.0.2
npm WARN node_modules/react-dom
npm WARN react-dom#"^17.0.2" from the root project
npm WARN 21 more (#coreui/react, #hookform/error-message, ...)
npm WARN
npm WARN Could not resolve dependency:
npm WARN peer react-dom#"^16.3.0" from #material-ui/utils#3.0.0-alpha.3
npm WARN node_modules/#material-ui/utils
npm WARN #material-ui/utils#"^3.0.0-alpha.2" from #material-ui/core#3.9.3
npm WARN node_modules/#material-ui/core
npm WARN
npm WARN Conflicting peer dependency: react-dom#16.14.0
npm WARN node_modules/react-dom
npm WARN peer react-dom#"^16.3.0" from #material-ui/utils#3.0.0-alpha.3
npm WARN node_modules/#material-ui/utils
npm WARN #material-ui/utils#"^3.0.0-alpha.2" from #material-ui/core#3.9.3
npm
2022-11-17T22:49:20.240Z [WARNING]: WARN node_modules/#material-ui/core
2022-11-17T22:49:28.722Z [WARNING]: npm ERR! code ERESOLVE
2022-11-17T22:49:28.725Z [WARNING]: npm ERR!
2022-11-17T22:49:28.725Z [WARNING]: ERESOLVE could not resolve
npm ERR!
npm ERR! While resolving: aws-appsync#4.0.5
npm ERR! Found: react#17.0.2
npm ERR! node_modules/react
npm ERR! react#"^17.0.2" from the root project
npm ERR! peer react#"^17.0.1" from #coreui/icons-react#1.1.0
npm ERR! node_modules/#coreui/icons-react
npm ERR! #coreui/icons-react#"^1.1.0" from the root project
npm ERR! 56 more (#coreui/react, #coreui/react-chartjs, #emotion/react, ...)
npm ERR!
2022-11-17T22:49:28.725Z [WARNING]:
npm ERR! Could not resolve dependency:
npm ERR! peer #react-native-community/async-storage#"^1.11.0" from aws-appsync#4.0.5
npm ERR! node_modules/aws-appsync
npm ERR! aws-appsync#"^4.0.3" from the root project
npm ERR! peer aws-appsync#"3.x.x || 4.x.x" from aws-appsync-react#4.0.5
npm ERR! node_modules/aws-appsync-react
npm ERR! aws-appsync-react#"^4.0.3" from the root project
npm ERR!
npm ERR! Conflicting peer dependency: react#16.14.0
npm ERR! node_modules/react
npm ERR! peer react#"^16.8" from #react-native-community/async-storage#1.12.1
npm ERR! node_modules/#react-native-community/async-storage
npm ERR! peer #react-native-community/async-storage#"^1.11.0" from aws-appsync#4.0.5
npm ERR! node_modules/aws-appsync
npm ERR! aws-appsync#"^4.0.3" from the root project
npm ERR! 1 more (aws-appsync-react)
npm ERR!
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR!
npm ERR! See /root/.npm/eresolve-report.txt for a full report.
2022-11-17T22:49:28.726Z [WARNING]: npm
2022-11-17T22:49:28.726Z [WARNING]: ERR! A complete log of this run can be found in:
npm ERR! /root/.npm/_logs/2022-11-17T22_49_16_301Z-debug-0.log
2022-11-17T22:49:28.737Z [ERROR]: !!! Build failed
2022-11-17T22:49:28.737Z [ERROR]: !!! Non-Zero Exit Code detected
2022-11-17T22:49:28.737Z [INFO]: # Starting environment caching...
2022-11-17T22:49:28.737Z [INFO]: # Uploading environment cache artifact...
2022-11-17T22:49:28.807Z [INFO]: # Uploaded environment cache artifact
2022-11-17T22:49:28.807Z [INFO]: # Environment caching completed
Terminating logging...
`
I tried redeploying previous successful builds, but that did help. I also tried changing the amplify.yaml file and adding --legacy-peer-deps to the end of the npm ci command and that also didn't solve the problem. I tried manually updating the libraries mentioned in the logs, that did't help either. I would really appreciate any suggestions in how to fix this. Thanks
I was trying to add a new feature to my web app, and what I was expecting was a successful build.

Answer 1

In order to run npm ci successfully with the --legacy-peer-deps flag, you should add a .npmrc file to your repository with the legacy peer dependencies enabled as below;
# ignore peerDependencies
legacy-peer-deps=true
It is important to add that your package-lock.json is equally required for the above to work as expected.