Change warning for placeholder size to exception

docs/configuration_reference/behavior_version.rst

@@ -22,7 +22,7 @@ and not listing legacy/deprecated parameters.
 Version History
 ---------------
 
-Behavior version 14 (2022-10-17)
+Behavior version 15 (2022-10-19)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Dimension tags with different dynamic size tensors
@@ -33,6 +33,19 @@ Otherwise it is likely a bug.
 
 See issue `#1141 <https://github.com/rwth-i6/returnn/issues/1141>`__.
 
+Behavior version 14 (2022-10-19)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The dim matching in :class:`DotLayer` is now more strict
+for the case that ``var1`` and ``var2`` are not provided,
+to figure out the common dims.
+
+If this causes problems to you,
+e.g. because you are not using dim tags consistently,
+then just specify ``var1`` and ``var2`` explicitly.
+
+See issue `#1154 <https://github.com/rwth-i6/returnn/issues/1154>`__.
+
 Behavior version 13 (2022-10-13)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

returnn/tf/util/data.py

@@ -12,6 +12,7 @@
 import tensorflow as tf
 import traceback
 
+import returnn.util.basic as util
 from returnn.util.basic import BehaviorVersion, NotSpecified, Entity
 import returnn.tf.compat as tf_compat
 
@@ -1001,7 +1002,7 @@ def declare_same_as(self, other):
             False,
             "Dim tags are same with different size placeholders (%r vs %r), please check external_data" % (
               self.dyn_size, other_same_base.dyn_size),
-            14)
+            15)
     # If we have a defined source, and this is a dynamic spatial axis, and it was undefined before,
     # maybe we can overtake the size_placeholder now.
     if other_same_base.dyn_size is not None and self.src_data:

returnn/util/basic.py

@@ -238,7 +238,7 @@ class BehaviorVersion:
   The version will be set after the config is defined at __main__.init_config() or Engine.__init__()
   """
 
-  _latest_behavior_version = 14
+  _latest_behavior_version = 15
   _behavior_version = None  # type: typing.Optional[int]
 
   @classmethod