Bug 5643

Summary:	??= with overrides doesn't work as expected
Product:	[Build System, Metadata & Runtime] BitBake	Reporter:	Koen Kooi <koen>
Component:	bitbake	Assignee:	Richard Purdie <richard.purdie>
Status:	RESOLVED NOTABUG	QA Contact:
Severity:	normal
Priority:	Undecided	CC:	kergoth, poky.bs.watcher, poky.watcher
Version:	unspecified
Target Milestone:	---
Hardware:	x86
OS:	Multiple
Whiteboard:
OS type for building Yocto:	---	Type of Regression:	---
Verified:		Documentation change:	Yes (doc changes required)

Description Koen Kooi 2013-12-06 19:22:29 UTC

FOO_override ?? = "true" in DISTRO.conf
FOO = "false" in recipe

Expected: bitbake -e recipe: FOO = false
Actual result: bitbake -e recipe: FOO = true

Comment 1 Richard Purdie 2013-12-08 09:49:59 UTC

That is in fact working as designed and true would be the expected result.

Why?

??= X means set this value to X if and only if nothing else sets it. So FOO_override is set to the supplied value X and then the override gets applied.