[PATCH v3 2/3] doc: bitbake-user-manual-metadata: remove invalid anonymous Python example

The documentation for inherit_defer suggested that conditional inheritance
can be achieved by setting a variable inside an anonymous python function
and then referencing it from inherit_defer.
This does not work: inherit_defer is resolved before the anonymous Python
functions run.

Replace the example with a warning explaining that anonymous Python
functions cannot be used to drive inherit_defer, since they run after
the directive has already been resolved.

Suggested-by: Quentin Schulz <[email protected]>
Signed-off-by: Dawid Bijak <[email protected]>
---
 .../bitbake-user-manual-metadata.rst          | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst b/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst
index ee6919dc4..52a9e7fa7 100644
--- a/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst
+++ b/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst
@@ -835,17 +835,6 @@ overrides::
    VARIABLE = ""
    VARIABLE:someoverride = "myclass"
 
-Another method is by using :ref:`anonymous Python
-<bitbake-user-manual/bitbake-user-manual-metadata:Anonymous Python Functions>`.
-Here is an example::
-
-   python () {
-       if condition == value:
-           d.setVar('VARIABLE', 'myclass')
-       else:
-           d.setVar('VARIABLE', '')
-   }
-
 Alternatively, you could use an inline Python expression in the
 following form::
 
@@ -859,6 +848,14 @@ In all cases, if the expression evaluates to an
 empty string, the statement does not trigger a syntax error because it
 becomes a no-op.
 
+.. warning::
+
+    Setting or modifying variables within an :ref:`anonymous Python function
+    <bitbake-user-manual/bitbake-user-manual-metadata:Anonymous Python Functions>`
+    will have no impact on the value of that variable in an
+    :ref:`inherit_defer <ref-bitbake-user-manual-metadata-inherit-defer>` directive
+    as the function is run after the directive is resolved.
+
 See also :term:`BB_DEFER_BBCLASSES` for automatically promoting classes
 ``inherit`` calls to ``inherit_defer``.
 
-- 
2.48.1