MuiThemeProvider removes extra fields from theme

• This is not a v0.x issue.
• I have searched the issues of this repository and believe that this is not a duplicate.

Expected Behavior 🤔

As with @material-ui/core@^3 the extra theme fields ( i.e. colors ) should not be removed

Current Behavior 😯

Any extra fields are removed after the created theme is passed to MuiThemeProvider and do not reach theme consumers.

Steps to Reproduce 🕹

Link:

1. git clone https://github.com/mateja176/react-hot-starter
2. cd react-hot-starter
3. git checkout material-ui-4
4. npm install
5. npm start
6. open console and compare PROVIDED theme and CONSUMED theme values

Context 🔦

Extend theme with additional color properties, i.e. success color for snackbar.

Your Environment 🌎

Tech	Version
Material-UI	v4.1.3
React Scripts	3.0.1
Browser	Chrome
TypeScript	3.5.1
etc.

[eps1lon]

@mateja176 Top of your console includes

It looks like there are several instances of @material-ui/styles initialized in this application. This may cause theme propagation issues, broken class names and makes your application bigger without a good reason.

See https://material-ui.com/r/styles-instance-warning for more info.

npm included multiple versions even though npm ls resulted in

├─┬ @material-ui/core@4.1.3
│ └── @material-ui/styles@4.1.2 
└── @material-ui/styles@4.1.2 

It shouldn’t install two versions. If I remove node_modules/@material-ui/core/node_modules/@material-ui/styles everything works as expected. Try regenerating your package-lock or try yarn.

If this doesn’t help please ask the question on stackoverflow and link it from here so that we can continue this conversation.

[mateja176]

@eps1lon On point, thank you so much! All that was required is:

rm package-lock.json
npm i

And @material-ui/styles@4.1.2 is now deduped

├─┬ @material-ui/core@4.1.3
│ ├── @material-ui/styles@4.1.2 deduped
├─┬ @material-ui/styles@4.1.2

My apologies, this was not directly related to @material-ui.