Prophet 1.1.7 bundles an incomplete CmdStan (2.33.1), causing all fits to fail in read-only notebook environments

[mgloel81]

Hi Prophet team,

I am currently running prophet as python model in dbt cloud with a bigquery adapter. Until 13th November 2025 It worked really smoothly using Bigquery Data frames and the colab notebook env it is tunning on.

It looks like after Prophet was upgraded to 1.1.7 in my managed notebook environment (BigQuery Notebook Execution / dbt Cloud), all Prophet models began failing with:

CmdStan installation missing makefile, path
/usr/local/lib/python3.12/dist-packages/prophet/stan_model/cmdstan-2.33.1 is invalid.

The Prophet 1.1.7 wheel includes a directory:

prophet/stan_model/cmdstan-2.33.1/

but the bundled CmdStan distribution inside is incomplete (missing makefile and other required build files).
cmdstanpy therefore rejects it immediately.
Because the environment is read-only, install_cmdstan() cannot repair the installation.

This makes Prophet 1.1.7 unusable in any environment where build tools or write access are restricted (BigQuery Notebook Execution, Colab Enterprise, certain serverless runtimes).
Prophet 1.1.5 worked correctly under the same constraints.

Could you please verify the CmdStan bundle inside the 1.1.7 wheels and republish a corrected build?
A valid bundled CmdStan is essential for Prophet to work in restricted notebook environments.

[tcuongd]

Sorry about that! We fixed the Makefile bundling in 1.2.1, although that also bumped the Cmdstan version. Can you upgrade to 1.2.1 in your managed environment?

[mgloel81]

Hi, thanks for your reply.
It's not that urgent I found a workaround using another forecasting method. However, it would be nice to make it work with prophet to compare performances of different models.

Unfortunately I cannot upgrade Prophet inside my environment.
The BigQuery Notebook Execution runtime (used by dbt Cloud) ships Prophet 1.1.7 preinstalled and blocks upgrades/downgrades.

When my dbt model runs:

Package 'prophet' is already installed and cannot be updated. Skipping.
The installed version: 1.1.7.

So I cannot install Prophet 1.2.1 or any other version.
I depend entirely on the version bundled in the managed runtime image.

Could you please escalate to Google / provide a wheel-level compatibility note so managed environments can pick up Prophet 1.2.1?