refactor!: default to only use the 'checkout' cache

We shouldn't set up a cache for every conceivable tool that's going to
be added to the `CACHES` config. Instead tasks should list out the ones
they need.

The checkout cache is going to be pretty standard and is a reasonable
default.

Author: ahal

src/taskgraph/transforms/run/common.py

@@ -175,7 +175,7 @@ def support_caches(
         use_caches = (
             config.graph_config.get("taskgraph", {})
             .get("run", {})
-            .get("use-caches", True)
+            .get("use-caches", ["checkout"])
         )
 
     for name, cache_cfg in CACHES.items():

test/test_transforms_run_run_task.py

@@ -55,36 +55,12 @@ def assert_docker_worker(task):
         "soft-dependencies": [],
         "worker": {
             "caches": [
-                {
-                    'mount-point': '/builds/worker/.task-cache/cargo',
-                    'name': 'cargo',
-                    'skip-untrusted': False,
-                    'type': 'persistent',
-                },
                 {
                     "mount-point": "/builds/worker/checkouts",
                     "name": "checkouts",
                     "skip-untrusted": False,
                     "type": "persistent",
                 },
-                {
-                    'mount-point': '/builds/worker/.task-cache/npm',
-                    'name': 'npm',
-                    'skip-untrusted': False,
-                    'type': 'persistent',
-                },
-                {
-                    'mount-point': '/builds/worker/.task-cache/pip',
-                    'name': 'pip',
-                    'skip-untrusted': False,
-                    'type': 'persistent',
-                },
-                {
-                    'mount-point': '/builds/worker/.task-cache/uv',
-                    'name': 'uv',
-                    'skip-untrusted': False,
-                    'type': 'persistent',
-                },
             ],
             "command": [
                 "/usr/local/bin/run-task",
@@ -95,19 +71,15 @@ def assert_docker_worker(task):
                 "echo hello world",
             ],
             "env": {
-                "CARGO_HOME": "/builds/worker/.task-cache/cargo",
                 "CI_BASE_REPOSITORY": "http://hg.example.com",
                 "CI_HEAD_REF": "default",
                 "CI_HEAD_REPOSITORY": "http://hg.example.com",
                 "CI_HEAD_REV": "abcdef",
                 "CI_REPOSITORY_TYPE": "hg",
                 "HG_STORE_PATH": "/builds/worker/checkouts/hg-store",
                 "MOZ_SCM_LEVEL": "1",
-                "PIP_CACHE_DIR": "/builds/worker/.task-cache/pip",
                 "REPOSITORIES": '{"ci": "Taskgraph"}',
-                "UV_CACHE_DIR": "/builds/worker/.task-cache/uv",
                 "VCS_PATH": "/builds/worker/checkouts/vcs",
-                "npm_config_cache": "/builds/worker/.task-cache/npm",
             },
             "implementation": "docker-worker",
             "os": "linux",
@@ -134,39 +106,19 @@ def assert_generic_worker(task):
                 'world"'
             ],
             "env": {
-                "CARGO_HOME": "{task_workdir}/.task-cache/cargo",
                 "CI_BASE_REPOSITORY": "http://hg.example.com",
                 "CI_HEAD_REF": "default",
                 "CI_HEAD_REPOSITORY": "http://hg.example.com",
                 "CI_HEAD_REV": "abcdef",
                 "CI_REPOSITORY_TYPE": "hg",
                 "HG_STORE_PATH": "y:/hg-shared",
                 "MOZ_SCM_LEVEL": "1",
-                "PIP_CACHE_DIR": "{task_workdir}/.task-cache/pip",
                 "REPOSITORIES": '{"ci": "Taskgraph"}',
-                "UV_CACHE_DIR": "{task_workdir}/.task-cache/uv",
                 "VCS_PATH": "{task_workdir}/build/src",
-                "npm_config_cache": "{task_workdir}/.task-cache/npm",
             },
             "implementation": "generic-worker",
             "mounts": [
-                {
-                    "cache-name": "cargo",
-                    "directory": ".task-cache/cargo",
-                },
                 {"cache-name": "checkouts", "directory": "build"},
-                {
-                    "cache-name": "npm",
-                    "directory": ".task-cache/npm",
-                },
-                {
-                    "cache-name": "pip",
-                    "directory": ".task-cache/pip",
-                },
-                {
-                    "cache-name": "uv",
-                    "directory": ".task-cache/uv",
-                },
                 {
                     "content": {
                         "url": "https://tc-tests.localhost/api/queue/v1/task/<TASK_ID>/artifacts/public/run-task"