Re: Variable key replaces original warnings

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Thu, 2015-07-30 at 17:03 +0200, Olof Johansson wrote:
> Hi all,
> 
> We've started to see issues on master like
> 
>    WARNING:
>      Variable key          USERADD_PARAM_${PN}             (; --system --home / --no-create-home --comment 'Storage manager daemon' --gid storage storage)
>      replaces original key USERADD_PARAM_recording-indexer (--system --home / --no-create-home --comment 'apache httpd' --gid www www).
> 
> (my alignment...)
> 
> The warning happens when doing
> 
>  WWWUSER_PACKAGE ?= "${PN}"
>  USERADD_PARAM_${WWWUSER_PACKAGE} := "--system --home / --no-create-home --gid www www"
> 
>  USERADD_PARAM_${PN}_append = "; --system --home / --no-create-home --gid username username"
> 
> (in reality, the first two lines are inherited from a class, and the third in
> the recipe itself.)
> 
> With bitbake -e I see what looks like the expected value, with both users being
> created. If I change USERADD_PARAM_${WWWUSER_PACKAGE} (second line) to
> USERADD_PARAM_${PN} no warning is printed, so this only seems to be a problem
> in cases where multiple unique non-expanded vars expand to the same expanded
> var.
> 
> I made a unit test that should demonstrate the problem (I think), and it fails
> because of the warnings:
> 
> diff --git a/bitbake/lib/bb/tests/data.py b/bitbake/lib/bb/tests/data.py
> index e9aab57..e7716cc 100644
> --- a/bitbake/lib/bb/tests/data.py
> +++ b/bitbake/lib/bb/tests/data.py
> @@ -386,6 +386,15 @@ class TestKeyExpansion(unittest.TestCase):
>              self.assertTrue(logContains("Variable key VAL_${FOO} (A) replaces original key VAL_foo (B)", logs))
>          self.assertEqual(self.d.getVar("VAL_foo", True), "A")
>  
> +    def test_append(self):
> +        self.d.setVar("TEST_${BAR}", "Bar")
> +        self.d.setVar("TEST_${FOO}_append", "Foo")
> +        with LogRecord() as logs:
> +            bb.data.expandKeys(self.d)
> +            self.assertFalse(logContains("Variable key TEST_${FOO} (Foo) replaces original key TEST_foo (Bar)", logs))
> +        self.assertEqual(self.d.getVar("TEST_${FOO}", True), "BarFoo")
> 
> 
> If you have any ideas on what this issue can be or how to fix it, please
> let me know :)

The data store changes recently caused a number of these to appear. The
issue has always been there, as has this warning, the new datastore code
just exposes it a bit more consistently than previously.

The reason we do this is that users with conflicting (different values)
of the same variable name usually have a metadata issue they're unaware
of.

The fix is to ensure you only set a variable in one canonical way.
OE-Core did show a few of these but I fixed them before merging the data
store changes.

Cheers,

Richard