[Build] Upgrading from 2.3 to 2.4 breaks the build

[franckboudraa]

Steps

• Install Semantic-UI 2.3.1 to root/src/semantic/
• Build with gulp build in root/src/semantic/
• Copy content of gist : https://gist.github.com/franckboudraa/0ab22ff1e29581c04041496aa54774fd
• Ok, the page is correctly displayed.
• Drop the dist/ folder in root/src/semantic/
• Update Semantic-UI to 2.4.2
• Build with gulp build in root/src/semantic/
• The page is no longer displayed correctly

Expected Result

Actual Result

Version

2.4.2

Testcase

No problem on 2.4.2 fresh install, only when upgrading from 2.3 to 2.4

[xeophin]

Happened to me as well. Upon checking my theme.config file, I realised that it didn't contain the new placeholder element, and added it between @loader and @rail, like this:

@loader     : 'default';
@placeholder: 'default';
@rail       : 'default';

Then the build process work again.

I guess the theme.config file isn't touched during updates, therefore missing the new component?

[franckboudraa]

Awesome, thank you @xeophin !

[reallistic]

Just happened to me. FWIW, the plumber error config seems to try to alert you of this but it is configured to check line 5 instead of line 9.

You can see this here:

Semantic-UI/tasks/config/tasks.js

Lines 96 to 103 in 52922d1

	if(error.filename.match(/theme.less/)) {
	if(error.line == 5) {
	element = regExp.variable.exec(error.message)[1];
	if(element) {
	console.error('Missing theme.config value for ', element);
	}
	console.error('Most likely new UI was added in an update. You will need to add missing elements from theme.config.example');
	}

The error I received (after manually logging it) is for line 9:

error { [Error: Recursive variable definition for @placeholder in file semantic/src/theme.less line no. 9]