chore: version bump 18.0.0

CHANGELOG.md

@@ -1,5 +1,25 @@
 # Change Log
 
+## [18.0.0] - 2025-11-17
+
+### Added
+
+- `--develop` flag to `taskgraph load-task` to support making source changes in a task
+
+### Fixed
+
+- BREAKING CHANGE: `run-task` no longer cleans up fetches dir (worker is already responsible for this)
+- Normalized certain known environment variables to use forward slashes in `run-task`
+- Added some additional environment variables to this normalization in `run-task`
+
+### Changed
+
+- `fetch-content` now uses `PERFHERDER_FETCH_CONTENT_JSON_PATH` for perf artifact
+
+### Removed
+
+- BREAKING CHANGE: Mercurial sparse profiles no longer supported in `run-task`
+
 ## [17.3.0] - 2025-11-07
 
 ### Added

docs/reference/migrations.rst

@@ -9,6 +9,11 @@ This page can help when migrating Taskgraph across major versions.
 * Stop setting the ``run.sparse-profile`` key in all tasks which perform a
   Mercurial clone. If sparse profiles are still required, the task must perform
   its own clone and not rely on the ``run-task`` script to do it.
+* `run-task` no longer cleans up the fetches directory. If using
+  `generic-worker`'s multiuser engine, this should have no impact. If you are
+  using a worker that does not create separate task workspaces and you require
+  the fetches dir to be cleaned up, adjust your tasks' commands to remove
+  `$MOZ_FETCHES_DIR` explicitly.
 
 16.x -> 17.x
 ------------

pyproject.toml

@@ -1,7 +1,7 @@
 ### Project
 [project]
 name = "taskcluster-taskgraph"
-version = "17.3.0"
+version = "18.0.0"
 description = "Build taskcluster taskgraphs"
 readme = "README.rst"
 authors = [