Add user guide to update MaxText dependencies with seed-env

docs/guides.md

@@ -33,4 +33,5 @@ guides/xprof_user_guide.md
 guides/checkpointing_solutions.md
 guides/megascale_hang_playbook.md
 guides/multimodal.md
+guides/update_dependencies.md
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docs/guides/update_dependencies.md

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+<!--
+ Copyright 2023-2025 Google LLC
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+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
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+      https://www.apache.org/licenses/LICENSE-2.0
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+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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+
+# How to update MaxText dependencies using seed-env
+
+## Introduction
+
+This document provides a guide to updating dependencies in MaxText using the `seed-env` tool. `seed-env` helps generate deterministic and reproducible Python environments by creating fully-pinned `requirements.txt` files from a base set of requirements.
+
+## Overview of the Process
+
+To update dependencies, you will follow these general steps:
+
+1.  **Modify Base Requirements**: Update the desired dependencies in `base_requirements/requirements.txt` or the hardware-specific files (`base_requirements/tpu-base-requirements.txt`, `base_requirements/gpu-base-requirements.txt`).
+2.  **Generate New Files**: Run the `seed-env` CLI tool to generate new, fully-pinned requirements files based on your changes.
+3.  **Update Project Files**: Copy the newly generated files into the `generated_requirements/` directory.
+4.  **Handle GitHub Dependencies**: Move any dependencies that are installed directly from GitHub from the generated files to `src/install_maxtext_extra_deps/extra_deps_from_github.txt`.
+5.  **Verify**: Test the new dependencies to ensure the project installs and runs correctly.
+
+The following sections provide detailed instructions for each step.
+
+## Step 1: Install seed-env
+
+First, you need to install the `seed-env` command-line tool by running `pip install seed-env uv`. Or follow the instructions in the
+[seed-env repository](https://github.com/google-ml-infra/actions/tree/main/python_seed_env#install-the-seed-env-tool) if you want to build `seed-env` from source.
+
+## Step 2: Find the JAX Build Commit Hash
+
+The dependency generation process is pinned to a specific nightly build of JAX. You need to find the commit hash for the desired JAX build.
+
+You can find the latest commit hashes in the [JAX `build/` folder](https://github.com/jax-ml/jax/commits/main/build). Choose a recent, successful build and copy its full commit hash.
+
+## Step 3: Generate the Requirements Files
+
+Next, run the `seed-env` CLI to generate the new requirements files. You will need to do this separately for the TPU and GPU environments. The generated files will be placed in a directory specified by `--output-dir`.
+
+### For TPU
+
+Run the following command, replacing `<jax-build-commit-hash>` with the hash you copied in the previous step.
+
+```bash
+seed-env \
+  --local-requirements=base_requirements/tpu-base-requirements.txt \
+  --host-name=MaxText \
+  --seed-commit=<jax-build-commit-hash> \
+  --python-version=3.12 \
+  --requirements-txt=tpu-requirements.txt \
+  --output-dir=generated_tpu_artifacts
+```
+
+### For GPU
+
+Similarly, run the command for the GPU requirements.
+
+```bash
+seed-env \
+  --local-requirements=base_requirements/cuda12-base-requirements.txt \
+  --host-name=MaxText \
+  --seed-commit=<jax-build-commit-hash> \
+  --python-version=3.12 \
+  --requirements-txt=cuda12-requirements.txt \
+  --hardware=cuda12 \
+  --output-dir=generated_gpu_artifacts
+```
+
+## 4. Update Project Files
+
+After generating the new requirements, you need to update the files in the MaxText repository.
+
+1.  **Copy the generated files:**
+    -   Move `generated_tpu_artifacts/tpu-requirements.txt` to `generated_requirements/tpu-requirements.txt`.
+    -   Move `generated_gpu_artifacts/cuda12-requirements.txt` to `generated_requirements/cuda12-requirements.txt`.
+
+2.  **Update `extra_deps_from_github.txt` (if necessary):**
+    Currently, MaxText uses a few dependencies, such as `mlperf-logging` and `google-jetstream`, that are installed directly from GitHub source. These are defined in `base_requirements/requirements.txt`, and the `seed-env` tool will carry them over to the generated requirements files.
+
+## 5. Verify the New Dependencies
+
+Finally, test that the new dependencies install correctly and that MaxText runs as expected.
+
+1.  **Create a clean environment:** It's best to start with a fresh Python virtual environment.
+
+```bash
+uv venv --python 3.12 --seed maxtext_venv
+source maxtext_venv/bin/activate
+```
+
+2.  **Run the setup script:** Execute `bash setup.sh` to install the new dependencies.
+
+```bash
+pip install uv
+# install the tpu package
+uv pip install -e .[tpu] --resolution=lowest
+# or install the gpu package by running the following line:
+# uv pip install -e .[cuda12] --resolution=lowest
+install_maxtext_github_deps
+```
+
+3.  **Run tests:** Run MaxText tests to ensure there are no regressions.