Opening external process, including web browser for online help, fails on Mac OS

[kasemir]

Since #3392 / #3395 moved the online help to an external web browser, I can no longer open the online help on a Mac.

java.io.IOException: Cannot run program "open": error=0, posix_spawn failed
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1170)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1089)
	at java.base/java.lang.Runtime.exec(Runtime.java:681)
	at java.base/java.lang.Runtime.exec(Runtime.java:530)
	at com.sun.javafx.application.HostServicesDelegate$StandaloneHostService.showDocument(HostServicesDelegate.java:139)
	at javafx.application.HostServices.showDocument(HostServices.java:115)
	at org.phoebus.ui.web.WebBrowserApplication.lambda$create$1(WebBrowserApplication.java:68)

It's not specific to help, it's more of a cannot-open-external-web-brower type of problem, since roughly the same error occurs when using the example "Actions" page and clicking the "Open Google" button:

java.io.IOException: Cannot run program "open": error=0, posix_spawn failed
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1170)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1089)
	at java.base/java.lang.Runtime.exec(Runtime.java:681)
	at java.base/java.lang.Runtime.exec(Runtime.java:530)
	at com.sun.javafx.application.HostServicesDelegate$StandaloneHostService.showDocument(HostServicesDelegate.java:139)
	at javafx.application.HostServices.showDocument(HostServices.java:115)
	at org.csstudio.display.builder.representation.javafx.JFXRepresentation.lambda$openWebBrowser$16(JFXRepresentation.java:1068)
	at org.csstudio.display.builder.representation.javafx.JFXRepresentation.execute(JFXRepresentation.java:682)
	at org.csstudio.display.builder.representation.javafx.JFXRepresentation.openWebBrowser(JFXRepresentation.java:1068)
	at org.csstudio.display.builder.runtime.app.actionhandlers.OpenWebPageActionHandler.lambda$handleAction$0(OpenWebPageActionHandler.java:41)

Likely caused by the JavaFX version.
This is with JFX 21.0.7+1 on Mac OS 15.4.1. The default web browser is Safari, as is tradition for Mac OS.

[georgweiss]

What about execute command with action button?

[kasemir]

Indeed, same problem. No matter if we use javafx.application.HostServices.showDocument to open a web page, which ends up calling java.lang.ProcessBuilder, or if we try to execute some other external command and also in the end call the ProcessBuilder, I get

posix_spawn failed
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1170)

Maybe it's a new Mac OS permission issue, need to allow the JRE to spawn external processes?

[georgweiss]

Yes, I would guess this is about MacOS and not JavaFX or the JVM.

[kasemir]

Looks like I had a damaged JDK. First it looked like one version of the JDK will get the above issues, but when updating that version with a new download, the problem went away...

[kasemir]

What was different about the broken JDK:
The file Contents/Home/lib/jspawnhelper was not executable.
chmod +x Contents/Home/lib/jspawnhelper fixed it...