pathwaycom/pathway · warning · NotImplementedError

Cannot plot diff table in a static mode

Error message

Cannot plot diff table in a static mode

What it means

The visualization helper for Pathway tables supports two rendering modes: a dynamic Bokeh view over updating tables and a static snapshot view. When bounded=True (diff-friendly rendering with _time/_diff handling) is combined with snapshot=True (static mode), the code explicitly raises NotImplementedError because static rendering of diff tables (with _diff coloring) is not implemented.

Source

Thrown at python/pathway/stdlib/viz/table_viz.py:124

        disabled=True,
        show_index=False,
        height=table_height,
        sorters=sorters,
        pagination="local",
        page_size=page_size,
        sizing_mode="stretch_width",
    )

    def color_negative_red(row):
        color = "red" if row["diff"] < 0 else "green"
        return [f"color: {color}" for _ in row]

    if not snapshot:
        dynamic_table.style.apply(color_negative_red, axis=1)  # type:ignore[union-attr]

    if bounded:
        if not snapshot:
            raise NotImplementedError(
                "Cannot plot diff table in a static mode"
            )  # todo: implement with support for _time and _diff
        [captured] = gr.run_tables(self)
        output_data = api.squash_updates(captured)
        keys = list(output_data.keys())
        dict_data = {
            name: [_format_types(output_data[key][index]) for key in keys]
            for index, name in enumerate(self._columns.keys())
        }
        dynamic_table.value = pd.DataFrame(dict_data)
    else:
        integrated = {}

        def update(key, row, time, is_addition):
            row["id"] = key
            if not snapshot:
                row["time"] = time
                row["diff"] = is_addition * 2 - 1

View on GitHub (pinned to fa2f74a464)

Solutions

  1. Set snapshot=False to render the dynamic diff-aware view
  2. Or keep snapshot=True but plot a non-diff (squashed/integrated) representation: materialize the table first (e.g. via pw.debug.compute_and_print-style capture or an io connector) and plot that snapshot table without bounded=True
  3. Check the viz call signature for your Pathway version; pass bounded/snapshot explicitly rather than relying on defaults

Example fix

# before
viz(table, snapshot=True, bounded=True)  # NotImplementedError

# after
viz(table, snapshot=False, bounded=True)  # dynamic diff view
Defensive patterns

Strategy: validation

Validate before calling

assert not (snapshot and bounded), 'diff-aware bounded rendering is unsupported in static snapshot mode; use snapshot=False'

Try / catch

try:
    viz(table, snapshot=True, bounded=True)
except NotImplementedError:
    viz(table, snapshot=False, bounded=True)

Prevention

When it happens

Trigger: Calling the table viz/plot API with bounded=True and snapshot=True on a table that produces diffs; using a static export helper (e.g. for docs/notebooks) on a table observed with updates; a wrapper that defaults to snapshot=True while the plot path defaults to bounded=True.

Common situations: Exporting pipeline state to a static HTML/screenshot where the code path chose diff-aware rendering; upgrading Pathway so viz defaults changed (snapshot for non-bokeh environments like CI headless rendering); plotting a table from an updating connector with the bounded flag copied from example code.

Related errors

AI-assisted analysis of pathwaycom/pathway@fa2f74a464 (2026-08-15). Data as JSON: /api/errors/a201ff29e9c6f8c2. Report an issue: GitHub.