style(types): enable type checking with ty (#407)

Signed-off-by: Alex Lowe <alex.lowe@canonical.com>

Author: lengau

Makefile

@@ -13,7 +13,7 @@ include common.mk
 format: format-ruff format-codespell format-prettier  ## Run all automatic formatters
 
 .PHONY: lint
-lint: lint-ruff lint-codespell lint-mypy lint-prettier lint-pyright lint-shellcheck lint-docs lint-twine  ## Run all linters
+lint: lint-ruff lint-ty lint-codespell lint-mypy lint-prettier lint-pyright lint-shellcheck lint-docs lint-twine  ## Run all linters
 
 .PHONY: pack
 pack: pack-pip  ## Build all packages
@@ -43,4 +43,18 @@ endif
 
 # If additional build dependencies need installing in order to build the linting env.
 .PHONY: install-lint-build-deps
-install-lint-build-deps:
+install-lint-build-deps: install-ty
+
+.PHONY: lint-ty
+lint-ty: install-ty
+	ty check
+
+.PHONY: install-ty
+install-ty:
+ifneq ($(shell which ty),)
+else ifneq ($(shell which snap),)
+	sudo snap install --beta astral-ty
+	sudo snap alias astral-ty.ty ty
+else ifneq ($(shell which uv),)
+	uv tool install ty
+endif

craft_cli/pytest_plugin.py

@@ -208,7 +208,9 @@ def assert_interactions(self, expected_call_list: list[_Call] | None) -> None:
         """
         if expected_call_list is None:
             if self.interactions:
-                show_interactions = "\n".join(map(str, self.interactions))
+                show_interactions = "\n".join(
+                    str(interaction) for interaction in self.interactions
+                )
                 raise AssertionError(
                     "Expected no call but really got:\n" + show_interactions
                 )

examples.py

@@ -606,6 +606,8 @@ def example_35() -> None:
 if func is None:
     print(f"ERROR: function {name!r} not found")
     sys.exit()
+# https://github.com/astral-sh/ty/issues/690
+assert func is not None  # noqa: S101, type narrowing
 
 if int(sys.argv[1]) != 29:  # noqa: PLR2004, magic value
     emit.init(EmitterMode.BRIEF, "examples", "Greetings earthlings")