migration/release-notes-5.1: document oeqa/selftest envvars change

This covers the Poky commit:
61186bc98a (oeqa/selftest: Only rewrite envvars paths that absolutely point to builddir, 2024-09-10)

(From yocto-docs rev: 59bfb63af0913ad69ae36691436af96d63dd657b)

Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Reviewed-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/migration-guides/migration-5.1.rst

@@ -141,3 +141,17 @@ QEMU changes
 Miscellaneous changes
 ~~~~~~~~~~~~~~~~~~~~~
 
+-  `oe-selftest` now only rewrites environment variable paths that absolutely
+   point to builddir (i.e ``X=$BUILDDIR/conf/`` is still rewritten to point to
+   the `oe-selftest` ``conf/`` directory but not ``Y=$BUILDDIR/../bitbake/`` which
+   still point to the ``bitbake/`` directory)
+
+   For example (taken from :yocto_ab:`autobuilder <>` environment):
+   :term:`BB_LOGCONFIG` is set as:
+   ``BB_LOGCONFIG="${BUILDDIR}/../bitbake/contrib/autobuilderlog.json"``.
+   Note the relative path starting from the build directory to outside of it.
+   This path is not changed by `oe-selftest` anymore.
+
+   Environment variables containing relative paths from tested build directory
+   to outside of the original build directory may need to be updated as they
+   won't be changed by `oe-selftest`.

documentation/migration-guides/release-notes-5.1.rst

@@ -26,6 +26,8 @@ New Features / Enhancements in 5.1
 
 -  Testing:
 
+   -  oeqa/selftest: Only rewrite envvars paths that absolutely point to builddir
+
 -  Utility script changes:
 
 -  BitBake improvements: