recipes: Update the note about the PR variable making it clear that it never

goes backwards and that you should always increase it if you are unsure
about what effect it has on the generated packages.

1 files changed, 11 insertions, 0 deletions

diff --git a/usermanual/chapters/recipes.xml b/usermanual/chapters/recipes.xml
index 3462c11acc..f889acd395 100644
--- a/usermanual/chapters/recipes.xml
+++ b/usermanual/chapters/recipes.xml
@@ -335,6 +335,17 @@ mv fixed.recipe.bb myrecipe.bb</screen></para>
         <para>It is good practice to always define PR in your recipes, even
         for the <emphasis>"r0"</emphasis> release, so that when editing the
         recipe it is clear that the PR number needs to be updated.</para>
+
+        <para>You should always increment PR when modifying a recipe.
+        Sometimes this can be avoided if the change will have no effect on the
+        actual packages generated by the recipe, such as updating the SRC_URI
+        to point to a new host. If in any doubt then you should increase the
+        PR regardless of what has been changed.</para>
+
+        <para>The PR value should never be decremented. If you accidentally
+        submit a large PR value for example then it should be left at the
+        value and just increased for new releases, not reset back to a lower
+        version. </para>
       </note></para>
 
     <para>When a recipe is being processed some variables are automatically