11905 2017-08-07 22:14:20 +0000 expandKeys() doesn't expand in definition order 2017-08-16 14:55:08 +0000 1 1 7 Build System, Metadata & Runtime BitBake bitbake unspecified x86 Multiple RESOLVED NOTABUG Undecided normal --- 1 haris.okanovic richard.purdie poky.bs.watcher poky.watcher --- --- No (bug/feature does not impact docs) oldest_to_newest 75703 0 haris.okanovic 2017-08-07 22:14:20 +0000 Consider the following bb snippet: VAR_foo = "base" AAA = "foo" BBB = "${AAA}" VAR_${BBB} = "wrong" VAR_${AAA} = "right" VAR_foo expands to "wrong", which is very unintuitive. The problem happens in lib.bb.data.expandKeys() which expands variables alphabetically instead of definition order. It first renames VAR_${AAA} --> VAR_foo == "right" then renames VAR_${BBB} --> VAR_foo --> "wrong", instead of the other way around. You can reproduce this in OpenEmbedded by simply copying the 5-line bb snippet above into any recipe X, and run `bitbake -e X | grep '^VAR_foo='` . 75897 1 richard.purdie 2017-08-16 14:55:08 +0000 Key expansion happens at a very specific time in the metadata when expandKeys is called. We don't dynamically expand keys. We also don't store the order of variable declaration as it makes very little sense to given the complexities of the overrides that are possible. I'd therefore argue that the current behaviour is correct and the only way bitbake can reasonably behave. Its clear and deterministic. I appreciate its not always 100% intuitive but I really can't see any other way the code can work, sorry.