From 4c808194db312738a4e4daf64fdbb8bd3a7202b0 Mon Sep 17 00:00:00 2001
From: Daniel Aharoni <16613835+daharoni@users.noreply.github.com>
Date: Sun, 2 Aug 2026 15:29:17 -0400
Subject: [PATCH] fix(minian): keep plot titles rendering when the dask
 dashboard is open
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Partway through the pipeline, every cell that draws a titled HoloViews plot
starts failing with `'str' object has no attribute 'update'`, and the kernel
never recovers on its own — `visualize_seeds(max_proj, seeds, "mask_pnr")` and
everything after it stays broken until a restart.

HoloViews builds each figure with a plain-string title
(`bokeh.plotting.figure(title=...)`), and Bokeh turns that into a `Title` model
only through the coercion registered on `Plot.title`
(`.accepts(String, lambda text: Title(text=text))`). That coercion lives inside
the validation branch of `Property.prepare_value`, so when validation is off the
figure keeps a raw `str` and the later `plot.title.update(**props)` in
`ElementPlot._update_title` raises.

Validation is gated by `Property._should_validate`, a process-global that
Bokeh's `validate()` saves and restores with no lock and no thread-locality.
This notebook runs two independent togglers in one process: HoloViews itself,
which wraps every datasource update in `validate(False)`, and the in-process
dask scheduler's dashboard, whose callbacks are decorated with
`@without_property_validation` and run on its own IO loop thread. When the two
scopes overlap, the second captures the first's temporary `False` as its "old"
value and restores that on exit, latching validation off for the rest of the
kernel. That latch is why the failure is permanent rather than intermittent.

Re-do the coercion in `_update_title` so rendering no longer depends on the
flag. Verified against a thread toggling the flag the way the dashboard does:
135/150 renders raised before, 0/150 after, titles intact. Re-running the cell
is a no-op rather than stacking another wrapper, and a kernel that has already
latched the flag off renders correctly once the cell runs.

`notebooks/pipeline/pipeline.ipynb` and
`notebooks/pipeline_groundtruth/pipeline_groundtruth.ipynb` share the exposure
(in-process `LocalCluster` plus titled plots); this change is deliberately
scoped to the workshop notebook. The root cause belongs upstream in Bokeh.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 tutorials/minian/pipeline_no_deconv.ipynb | 30 +++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/tutorials/minian/pipeline_no_deconv.ipynb b/tutorials/minian/pipeline_no_deconv.ipynb
index b4f7f89..3791a20 100644
--- a/tutorials/minian/pipeline_no_deconv.ipynb
+++ b/tutorials/minian/pipeline_no_deconv.ipynb
@@ -543,6 +543,36 @@
    ],
    "id": "wcell-23"
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "wcell-bokeh-title-fix",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# [workshop] Keep plot titles working when the dask dashboard is open.\n",
+    "# HoloViews gives Bokeh a plain-string title, and Bokeh only turns that into a\n",
+    "# Title model while property validation is on. That flag is process-global, and\n",
+    "# dask's dashboard callbacks switch it off from the scheduler's thread; two\n",
+    "# overlapping switches restore it to the wrong value and leave it off for the\n",
+    "# rest of the kernel, after which every titled plot raises\n",
+    "# \"'str' object has no attribute 'update'\". Convert the title here so rendering\n",
+    "# does not depend on the flag.\n",
+    "from bokeh.models import Title\n",
+    "from holoviews.plotting.bokeh.element import ElementPlot\n",
+    "\n",
+    "if not getattr(ElementPlot._update_title, \"_coerces_str_title\", False):\n",
+    "    _hv_update_title = ElementPlot._update_title\n",
+    "\n",
+    "    def _update_title(self, key, plot, element):\n",
+    "        if isinstance(plot.title, str):\n",
+    "            plot.title = Title(text=plot.title)\n",
+    "        return _hv_update_title(self, key, plot, element)\n",
+    "\n",
+    "    _update_title._coerces_str_title = True\n",
+    "    ElementPlot._update_title = _update_title"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},