Hey @areknow thank you very much for reporting this, but I cannot reproduce this in stackblitz
https://stackblitz.com/edit/github-yp9pwy?file=src/expandable-section/expandable-section-default-example/expandable-section-default-example.html

Furthermore, when I look at the code the coerceBooleanProperty is used. 🤔

Are you sure that you use the component correctly?

https://github.com/dynatrace-oss/barista/blob/master/libs/barista-components/expandable-section/src/expandable-section.ts#L76

  @Input()
  get expanded(): boolean {
    return this._panel.expanded;
  }
  set expanded(value: boolean) {
    this._panel.expanded = coerceBooleanProperty(value);
    this._changeDetectorRef.markForCheck();
  }

Hi @lukasholzer! I also was not able to reproduce in stackblitz so I created a minimal repo. This might indicate an issue with ivy which is not happening with view renderer. Were you able to clone the repo and see the console error?

Hello @lukasholzer,
I'm also able to reproduce the issue, with the shorthand notation for the directive.

@areknow Could you try to use the material expandable in your app and compare the behavior. I am curious whether we have some compilation issue with ivy compatibility. This would be a minimal setup https://stackblitz.com/edit/angular-rubmxc?file=src/app/expansion-steps-example.html

@areknow I cloned your repo did an npm install and now an ng serve:

besides that please update the highcharts version and remove the @types/highcharts

@ffriedl89 I imported the MatExpansionModule and added the component markup to the project, it runs perfectly fine with the shorthand directive notation.

@lukasholzer I removed @types/highcharts and updated highcharts to the latest version. Still the same issue:

core.js:6185 ERROR TypeError: Cannot set property 'expanded' of undefined
    at DtExpandableSection.set expanded [as expanded] (dynatrace-barista-components-expandable-section.js:79)
    at Object.ngOnChangesSetInput [as setInput] (core.js:26879)
    at setInputsFromAttrs (core.js:13039)
    at instantiateAllDirectives (core.js:12752)
    at createDirectivesInstances (core.js:11989)
    at Module.ɵɵelementStart (core.js:21043)
    at AppComponent_Template (app.component.html:1)
    at executeTemplate (core.js:11949)
    at renderView (core.js:11735)
    at renderComponent (core.js:13244)

@areknow i put the not-reproduceable label on it as I see the error above when I want to serve the app. So i cannot serve the application.

It is not possible to let your repo run for me.

Steps I made:

1. git clone ...
2. npm install
3. ng serve

@lukasholzer I have run the repo on three separate machines. Not sure what the issue is, its a super basic project 🤔
@josecolella @toddbaert have also run the repo and have seen the same issue.

~/Desktop/test
❯ git clone https://github.com/areknow/a-expandable-section-demo.git .
Cloning into '.'...
remote: Enumerating objects: 47, done.
remote: Counting objects: 100% (47/47), done.
remote: Compressing objects: 100% (37/37), done.
remote: Total 47 (delta 10), reused 45 (delta 8), pack-reused 0
Unpacking objects: 100% (47/47), done.

~/Desktop/test master
❯ ls
README.md          angular.json       browserslist       e2e                karma.conf.js      package-lock.json  package.json       src                tsconfig.app.json  tsconfig.json      tsconfig.spec.json tslint.json

~/Desktop/test master
❯ npm i

> [email protected] install /Users/arnaud.crowther/Desktop/test/node_modules/watchpack-chokidar2/node_modules/fsevents
> node install.js

No receipt for 'com.apple.pkg.CLTools_Executables' found at '/'.

No receipt for 'com.apple.pkg.DeveloperToolsCLILeo' found at '/'.

No receipt for 'com.apple.pkg.DeveloperToolsCLI' found at '/'.

gyp: No Xcode or CLT version detected!
gyp ERR! configure error
gyp ERR! stack Error: `gyp` failed with exit code: 1
gyp ERR! stack     at ChildProcess.onCpExit (/Users/arnaud.crowther/.nvm/versions/node/v12.16.1/lib/node_modules/npm/node_modules/node-gyp/lib/configure.js:351:16)
gyp ERR! stack     at ChildProcess.emit (events.js:311:20)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:275:12)
gyp ERR! System Darwin 19.5.0
gyp ERR! command "/Users/arnaud.crowther/.nvm/versions/node/v12.16.1/bin/node" "/Users/arnaud.crowther/.nvm/versions/node/v12.16.1/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
gyp ERR! cwd /Users/arnaud.crowther/Desktop/test/node_modules/watchpack-chokidar2/node_modules/fsevents
gyp ERR! node -v v12.16.1
gyp ERR! node-gyp -v v5.1.0
gyp ERR! not ok

> [email protected] install /Users/arnaud.crowther/Desktop/test/node_modules/webpack-dev-server/node_modules/fsevents
> node install.js

No receipt for 'com.apple.pkg.CLTools_Executables' found at '/'.

No receipt for 'com.apple.pkg.DeveloperToolsCLILeo' found at '/'.

No receipt for 'com.apple.pkg.DeveloperToolsCLI' found at '/'.

gyp: No Xcode or CLT version detected!
gyp ERR! configure error
gyp ERR! stack Error: `gyp` failed with exit code: 1
gyp ERR! stack     at ChildProcess.onCpExit (/Users/arnaud.crowther/.nvm/versions/node/v12.16.1/lib/node_modules/npm/node_modules/node-gyp/lib/configure.js:351:16)
gyp ERR! stack     at ChildProcess.emit (events.js:311:20)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:275:12)
gyp ERR! System Darwin 19.5.0
gyp ERR! command "/Users/arnaud.crowther/.nvm/versions/node/v12.16.1/bin/node" "/Users/arnaud.crowther/.nvm/versions/node/v12.16.1/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
gyp ERR! cwd /Users/arnaud.crowther/Desktop/test/node_modules/webpack-dev-server/node_modules/fsevents
gyp ERR! node -v v12.16.1
gyp ERR! node-gyp -v v5.1.0
gyp ERR! not ok

> [email protected] postinstall /Users/arnaud.crowther/Desktop/test/node_modules/core-js
> node -e "try{require('./postinstall')}catch(e){}"


> @angular/[email protected] postinstall /Users/arnaud.crowther/Desktop/test/node_modules/@angular/cli
> node ./bin/postinstall/script.js

added 1391 packages from 1132 contributors and audited 1393 packages in 20.393s

41 packages are looking for funding
  run `npm fund` for details

found 5 vulnerabilities (3 low, 2 high)
  run `npm audit fix` to fix them, or `npm audit` for details

~/Desktop/test master 22s
❯ ng serve
0% compiling
Compiling @angular/core : es2015 as esm2015

Compiling @angular/common : es2015 as esm2015

Compiling @angular/platform-browser : es2015 as esm2015

Compiling @angular/platform-browser-dynamic : es2015 as esm2015

Compiling @angular/common/http : es2015 as esm2015

Compiling @angular/cdk/platform : es2015 as esm2015

Compiling @angular/cdk/bidi : es2015 as esm2015

Compiling @angular/cdk/collections : es2015 as esm2015

Compiling @angular/cdk/scrolling : es2015 as esm2015

Compiling @angular/cdk/keycodes : es2015 as esm2015

Compiling @angular/cdk/observers : es2015 as esm2015

Compiling @angular/cdk/a11y : es2015 as esm2015

Compiling @angular/cdk/tree : es2015 as esm2015

Compiling @angular/animations : es2015 as esm2015

Compiling @angular/forms : es2015 as esm2015

Compiling @angular/cdk/portal : es2015 as esm2015

Compiling @angular/cdk/overlay : es2015 as esm2015

Compiling @dynatrace/barista-components/core : es2015 as esm2015

Compiling @dynatrace/barista-components/icon : es2015 as esm2015

Compiling @angular/animations/browser : es2015 as esm2015

Compiling @angular/platform-browser/animations : es2015 as esm2015

Compiling @angular/cdk/table : es2015 as esm2015

Compiling @angular/cdk/drag-drop : es2015 as esm2015

Compiling @dynatrace/barista-components/button : es2015 as esm2015

Compiling @dynatrace/barista-components/indicator : es2015 as esm2015

Compiling @dynatrace/barista-components/empty-state : es2015 as esm2015

Compiling @dynatrace/barista-components/form-field : es2015 as esm2015

Compiling @dynatrace/barista-components/formatters : es2015 as esm2015

Compiling @angular/cdk/text-field : es2015 as esm2015

Compiling @dynatrace/barista-components/input : es2015 as esm2015

Compiling @dynatrace/barista-components/checkbox : es2015 as esm2015

Compiling @dynatrace/barista-components/pagination : es2015 as esm2015

Compiling @dynatrace/barista-components/table : es2015 as esm2015

Compiling @dynatrace/barista-components/expandable-panel : es2015 as esm2015

Compiling @dynatrace/barista-components/expandable-section : es2015 as esm2015

Compiling @angular/cdk/accordion : es2015 as esm2015

Compiling @angular/material/expansion : es2015 as esm2015

chunk {main} main.js, main.js.map (main) 14 kB [initial] [rendered]
chunk {polyfills} polyfills.js, polyfills.js.map (polyfills) 150 kB [initial] [rendered]
chunk {runtime} runtime.js, runtime.js.map (runtime) 6.15 kB [entry] [rendered]
chunk {styles} styles.js, styles.js.map (styles) 108 kB [initial] [rendered]
chunk {vendor} vendor.js, vendor.js.map (vendor) 4.99 MB [initial] [rendered]
Date: 2020-08-12T15:43:23.068Z - Hash: 1ecde4c6e7201f777336 - Time: 57275ms
** Angular Live Development Server is listening on localhost:4200, open your browser on http://localhost:4200/ **
: Compiled successfully.

Date: 2020-08-12T15:43:24.031Z - Hash: 1ecde4c6e7201f777336
5 unchanged chunks

Time: 537ms
: Compiled successfully.

@lukasholzer Following the commands stated in your post, I'll able to run the project without any issue

@lukasholzer I, too, have been able to reproduce the issue with successful compilation message.

1. Cloned git repo
2. npm install
3. ng serve

Results:

@areknow hey @thomaspink and myself found the issue we will fix! :) Wondering how this can work even in VE as we are trying to set a property on the setter which is a viewChild so later Lifecycle. 🤔

Is this an urgent fix for you or are you ok to get it with 8.0.0 otherwise we have to do a backport for this issue.

Fixed by PR #1491

@lukasholzer thats great news! I performed a hot fix for my app, so I can wait till 8.0.0. Thanks!