tensorflow/models · error · ValueError

steps should be an Tensor. Python object may cause retracing

Error message

steps should be an Tensor. Python object may cause retracing.

What it means

Error "steps should be an Tensor. Python object may cause retracing." thrown in tensorflow/models.

Source

Thrown at official/legacy/bert/model_training_utils.py:369

      # For reporting, the metric takes the mean of losses.
      train_loss_metric.update_state(raw_loss)
      for metric in train_metrics:
        metric.update_state(labels, model_outputs)

    @tf.function
    def train_steps(iterator, steps):
      """Performs distributed training steps in a loop.

      Args:
        iterator: the distributed iterator of training datasets.
        steps: an tf.int32 integer tensor to specify number of steps to run
          inside host training loop.

      Raises:
        ValueError: Any of the arguments or tensor shapes are invalid.
      """
      if not isinstance(steps, tf.Tensor):
        raise ValueError('steps should be an Tensor. Python object may cause '
                         'retracing.')

      for _ in tf.range(steps):
        strategy.run(_replicated_step, args=(next(iterator),))  # pyrefly: ignore[missing-attribute]

    def train_single_step(iterator):
      """Performs a distributed training step.

      Args:
        iterator: the distributed iterator of training datasets.

      Raises:
        ValueError: Any of the arguments or tensor shapes are invalid.
      """
      strategy.run(_replicated_step, args=(next(iterator),))  # pyrefly: ignore[missing-attribute]

    def test_step(iterator):
      """Calculates evaluation metrics on distributed devices."""

View on GitHub (pinned to e006f5f0d5)

When it happens

Trigger: Thrown at official/legacy/bert/model_training_utils.py:369 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of tensorflow/models@e006f5f0d5 (2026-08-24). Data as JSON: /api/errors/f0af70b984d5d800. Report an issue: GitHub.