[IMP] qweb: Allow to propagate value to variables outside the loop.

If the variable was existing outside the context of the ``foreach``,
the value is copied at the end of the foreach into the global context.

Fix #4461 - Q74531 - Q71486 - Q71675

1 files changed, 20 insertions, 0 deletions

diff --git a/doc/reference/qweb.rst b/doc/reference/qweb.rst
index a7564ded394..30ef4c25196 100644
--- a/doc/reference/qweb.rst
+++ b/doc/reference/qweb.rst
@@ -158,6 +158,26 @@ variables for various data points:
     a boolean flag indicating that the current iteration round is on an odd
     index
 
+
+These extra variables provided and all new variables created into the
+``foreach`` are only available in the scope of the``foreach``. If the
+variable exists outside the context of the ``foreach``, the value is copied
+at the end of the foreach into the global context.
+
+::
+
+    <t t-set="existing_variable" t-value="False"/>
+    <!-- existing_variable now False -->
+
+    <p t-foreach="[1, 2, 3]" t-as="i">
+        <t t-set="existing_variable" t-value="True"/>
+        <t t-set="new_variable" t-value="True"/>
+        <!-- existing_variable and new_variable now True -->
+    </p>
+
+    <!-- existing_variable always True -->
+    <!-- new_variable undefined -->
+
 .. _reference/qweb/attributes:
 
 attributes