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From: Richard Purdie <richard.purdie@linuxfoundation.org>
To: Paulo Neves <ptsneves@gmail.com>, OE-core
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Subject: Re: [meta-oe][PATCH 1/3] testimage: Refactoring and fixing.
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On Sun, 2018-08-12 at 21:49 +0200, Paulo Neves wrote:
> I found a bug in my code where changing a variable, for example in
> layer.conf does not re-trigger the generation of the json file
> containing the data store at the time of image creation. The json
> file is generated in
> ROOTFS_POSTPROCESS_COMMAND += "write_image_test_data ; " @
> meta/classes/rootfs-postcommands.bbclass.
> 
> Can anybody tell me if changing a variable in the datastore and
> accessing it in the postprocess_command will never trigger the
> postprocess_command? It happens that in this case this variable is
> not important for the rootfs task itself but only for the post-
> process.

The system has no insight into which variables that command might be
accessing so it doesn't know when to rerun it. Adding a dependency on
all variables would mean the rootfs would get continually rewritten.

I don't like the json usage in testimage for this reason as it
effectively breaks our data dependencies and handling in order to be
able to run standalone. Pros and cons I guess, this is one of the
downsides. Not sure there is much that can be done about it.

Cheers,

Richard