Refactor the content model of step to avoid UPA issues

diff --git a/docbook/relaxng/docbook/src/pool.rnc b/docbook/relaxng/docbook/src/pool.rnc
index 670ae640f8f3780d635920a72972f34f1873c339..5654e74690b206644852675c1b7227bed2c8ee41 100644 (file)
--- a/docbook/relaxng/docbook/src/pool.rnc
+++ b/docbook/relaxng/docbook/src/pool.rnc
@@ -1243,12 +1243,13 @@ div {
 
    db.step.info = db._info.title.only
 
+   # This content model is blocks*, step|stepalternatives, blocks* but
+   # expressed this way it avoids UPA issues in XSD and DTD versions
    db.step = element step {
       db.step.attlist,
       db.step.info,
-      db.all.blocks*,
-      (db.substeps|db.stepalternatives)?,
-      db.all.blocks*
+      ((db.all.blocks+, (((db.substeps|db.stepalternatives), db.all.blocks*))?)
+       | ((db.substeps|db.stepalternatives), db.all.blocks*))
    }
 }