chore: version bump 17.0.0

CHANGELOG.md

@@ -1,5 +1,32 @@
 # Change Log
 
+## [17.0.0] - 2025-10-17
+
+### Changed
+
+- BREAKING CHANGE: Dropped support for Python 3.8
+- BREAKING CHANGE: `base_ref` parameter no longer gets reset to default branch by Decision task
+- BREAKING CHANGE: `base_rev` parameter no longer gets reset to merge-base by Decision task
+- BREAKING CHANGE: `run-task` script no longer fetches or checks out `base_ref` parameter
+- BREAKING CHANGE: `run-task` script no longer fetches all heads if `head_ref` was not specified
+
+### Added
+
+- `run-task` now supports shallow Git clones
+- Improved support for shallow clones in `repo.get_changed_files()`
+
+### Perf
+
+- Improvements to graph traversal logic and caching
+
+### Fixed
+
+- Bug in `retrigger-multiple` action's schema definition
+- `run-task` no longer fetches head ref twice in some scenarios
+- `run-task` avoids fetching tags in some scenarios when not necessary
+- `run-task` properly normalizes `head_ref` before checking it out
+- Appropriate exception now being caught in various `taskcluster` call sites
+
 ## [16.2.1] - 2025-10-14
 
 ### Fixed

docs/reference/migrations.rst

@@ -3,6 +3,38 @@ Migration Guide
 
 This page can help when migrating Taskgraph across major versions.
 
+16.x -> 17.x
+------------
+
+* Upgrade to Python 3.9 or above.
+* The ``base_ref`` parameter could now be ``None`` if it wasn't explicitly
+  passed into the Decision task. If this was relied upon, do the following
+  instead:
+
+  .. code-block:: python
+
+     from taskgraph.util.vcs import get_repository
+
+     repo = get_repository()
+     base_ref = repo.default_branch
+
+* The ``base_rev`` parameter is no longer being reset to the merge-base. This
+  means in some cases, ``base_rev`` might not actually be an ancestor of
+  ``head_rev``. If you need the merge-base, you can use:
+
+  .. code-block:: python
+
+     from taskgraph.util.vcs import get_repository
+
+     repo = get_repository()
+     base_rev = repo.find_latest_common_revision(parameters["base_rev"], parameters["head_rev"])
+
+* The ``base_ref`` is no longer being fetched by ``run-task``. If you were
+  relying on it, you can run ``git fetch origin <base_ref>`` in a subprocess.
+* The ``run-task`` scripts no longer fetches all heads when ``head_ref`` isn't
+  specified. If this behaviour was relied upon, you can run
+  ``git fetch +refs/heads/*:refs/remotes/work/*`` in a subprocess.
+
 15.x -> 16.x
 ------------
 

pyproject.toml

@@ -1,7 +1,7 @@
 ### Project
 [project]
 name = "taskcluster-taskgraph"
-version = "16.2.1"
+version = "17.0.0"
 description = "Build taskcluster taskgraphs"
 readme = "README.rst"
 authors = [