Update releng/release-notes-next/generate_buildrequires.bug

with suggestion from Miro Hroncok

Co-authored-by: Miro Hrončok <[email protected]>

releng/release-notes-next/generate_buildrequires.bug

@@ -1,5 +1,17 @@
-Previously Mock skipped %prep section when doing the next round of build of `%generate_buildrequries` to save time.
-But we found that when the package deletes `setupmeta.egg-info` in `%prep`, then the next loop can work with incorrect data
-and generate incorrect build requires that may not be satisfied.
-Mock now calls `%prep` section in every loop. This may result in a few seconds of delay when spec file uses
-`%generate_buildrequries`, but generated build dependency is correct now.
+To save time, Mock previously skipped the `%prep` section when building
+an RPM package after completing the installation of all the requirements
+generated by `%generate_buildrequries`.
+
+However, when the `%generate_buildrequries` section has side effects altering
+the results of a subsequent run of self,
+then the final build may work with different data and generate incorrect
+build requirements that may not be actually installed during the build.
+In extreme case, it is possible to successfully build a package with
+unsatisfiable BuildRequires in the built SRPM metadata.
+
+Mock now calls `%prep` section even during the final build after completing
+the installation of all the generated build requirements.
+This may result in a few seconds of delay when spec file uses
+`%generate_buildrequries` but the source used to generate the build requirements
+is more likely to stay consistent during the build,
+making it harder to accidentally generate unsatisfied BuildRequires.