Docs: Add Google Colab TPU runtime installation guide and troubleshooting

docs/source/colab_tpu.rst

@@ -0,0 +1,110 @@
+Using malariagen_data on Google Colab (TPU Runtime)
+===================================================
+
+Overview
+--------
+
+When using a Google Colab **v2-8 TPU runtime**, installing ``malariagen_data`` may fail due to a dependency conflict with a preinstalled system package.
+
+Colab TPU runtimes ship with:
+
+- ``blinker==1.4`` installed via distutils/system packages
+
+During installation, ``dash`` → ``Flask`` requires:
+
+- ``blinker>=1.6.2``
+
+Because the preinstalled version is a distutils-installed package, ``pip`` cannot uninstall it, and installation fails with:
+
+::
+
+    error: uninstall-distutils-installed-package
+
+    × Cannot uninstall blinker 1.4
+    ╰─> It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.
+
+This issue appears specific to the TPU runtime image.
+
+Reproducing the Issue
+---------------------
+
+1. Open Google Colab
+2. Select **Runtime → Change runtime type**
+3. Choose **TPU**
+4. Run:
+
+::
+
+    pip install malariagen_data
+
+Installation fails due to the ``blinker`` conflict described above.
+
+Recommended Workaround
+----------------------
+
+Step 1 — Install core package without dependencies:
+
+::
+
+    pip install malariagen_data --no-deps
+
+Step 2 — Install required dependencies manually:
+
+::
+
+    pip install \
+      "anjl>=1.2.0" \
+      bed_reader \
+      biopython \
+      "dash<3.0.0" \
+      "dash-cytoscape>=1.0.0" \
+      distributed \
+      gcsfs \
+      "igv-notebook>=0.2.3" \
+      "ipinfo!=4.4.1" \
+      "ipyleaflet>=0.17.0" \
+      "numcodecs<0.16" \
+      "protopunica>=0.14.8.post2" \
+      s3fs \
+      statsmodels \
+      yaspin \
+      "zarr<3.0.0,>=2.11" \
+      "bokeh<3.7.0" \
+      "numpy<2.2" \
+      xarray \
+      scikit-allel
+
+After installation, restart the runtime.
+
+Cloud Data Access (GCS)
+-----------------------
+
+Most datasets are hosted on Google Cloud Storage.
+
+If you see errors such as:
+
+::
+
+    403: Permission denied on storage.objects.get
+
+Authenticate your Colab session:
+
+::
+
+    from google.colab import auth
+    auth.authenticate_user()
+
+You may also need to request access to certain datasets:
+https://forms.gle/d1NV3aL3EoVQGSHYA
+
+Troubleshooting
+---------------
+
+Check which version of ``blinker`` is installed:
+
+::
+
+    pip show blinker
+    python -c "import blinker; print(blinker.__version__)"
+
+If version ``1.4`` is installed under ``/usr/lib/python3/dist-packages``, this indicates the TPU system package.

docs/source/index.rst

@@ -79,6 +79,13 @@ via pip::
 
    pip install malariagen_data
 
+.. note::
+
+   If you are using Google Colab with a **TPU runtime**, installation may fail due to
+   a dependency conflict with a preinstalled system package (``blinker==1.4``).
+
+   See :doc:`colab_tpu` for detailed instructions and troubleshooting.
+
 For accessing data in Google Cloud Storage (GCS) you will also need to authenticate with Google Cloud.
 
 If you are using ``malariagen_data`` from within Google Colab, authentication will be automatically