added and all the contracts are kept

.github/workflows/_test.yml

@@ -49,6 +49,10 @@ jobs:
         with:
           python-version: ${{ inputs.python-version }}
           pip-install: ".[dev]"
+
+      - name: Run import linter
+        run: lint-imports
+
       - name: Run tests
         run: tox -e tests
 

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
     uses: ./.github/workflows/_tox.yml
     with:
       tox: pre-commit,type-checking
-
+  
   test:
     needs: check
     if: needs.check.outputs.branch-pr == ''

.pre-commit-config.yaml

@@ -22,3 +22,11 @@ repos:
         entry: ruff format --force-exclude
         types: [python]
         require_serial: true
+
+      - id: import-contracts
+        name: Ensure import directionality
+        pass_filenames: false
+        language: system
+        entry: lint-imports
+        types: [python]
+        require_serial: false

pyproject.toml

@@ -42,6 +42,7 @@ dev = [
     "inflection",
     "ipython",
     "ipywidgets",
+    "import-linter",
     "matplotlib",
     "myst-parser",
     "numpydoc",
@@ -164,3 +165,41 @@ lint.preview = true # so that preview mode PLC2701 is enabled
 # See https://github.com/DiamondLightSource/python-copier-template/issues/154
 # Remove this line to forbid private member access in tests
 "tests/**/*" = ["SLF001"]
+
+
+[tool.importlinter]
+root_package = "ophyd_async"
+
+[[tool.importlinter.contracts]]
+name = "Core is independent"
+type = "independence"
+modules = "ophyd_async.core"
+
+[[tool.importlinter.contracts]]
+name = "Epics depends only on core"
+type = "forbidden"
+source_modules = "ophyd_async.epics"
+forbidden_modules = [
+    "ophyd_async.fastcs",
+    "ophyd_async.plan_stubs",
+    "ophyd_async.sim",
+    "ophyd_async.tango",
+]
+
+[[tool.importlinter.contracts]]
+name = "tango depends only on core"
+type = "forbidden"
+source_modules = "ophyd_async.tango"
+forbidden_modules = [
+    "ophyd_async.fastcs",
+    "ophyd_async.plan_stubs",
+    "ophyd_async.sim",
+    "ophyd_async.epics",
+]
+
+
+[[tool.importlinter.contracts]]
+name = "Fastcs depends only on core, epics, tango"
+type = "forbidden"
+source_modules = "ophyd_async.fastcs"
+forbidden_modules = ["ophyd_async.plan_stubs", "ophyd_async.sim"]