Add support for dependency groups

docs/usage/configuration.md

@@ -586,6 +586,30 @@ In most cases you should not need to specify `rename` manually (see the Note bel
     distribution metadata to map module names like 'git' to their distributions
     ('GitPython').
 
+### Dependency Groups (PEP 735)
+
+Tach supports [PEP 735 dependency groups](https://peps.python.org/pep-0735/). By default, Tach will include dependencies from the `dev` dependency group when checking external dependencies.
+
+To configure which dependency groups to include, add `[tool.tach.external]` to your `pyproject.toml`:
+
+```toml
+# In pyproject.toml
+[dependency-groups]
+dev = ["ruff", "mypy"]
+test = ["pytest", "coverage"]
+
+[tool.tach.external]
+include_dependency_groups = ["dev", "test"]
+```
+
+This configuration is read from each package's `pyproject.toml`, making it suitable for monorepos where different packages may have different dependency groups.
+
+Special values:
+- `["all"]` - include all dependency groups
+- `[]` - disable dependency groups entirely (only use `[project.dependencies]`)
+
+If `[tool.tach.external]` is not specified, Tach defaults to `["dev"]`.
+
 ## Rules
 
 Tach allows configuring the severity of certain issues. Each entry in the `rules` table can be set to `error`, `warn`, or `off`.

public/tach-toml-schema.json

@@ -249,6 +249,13 @@
             "type": "string"
           },
           "description": "List of external dependency names to ignore during checks"
+        },
+        "rename": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "description": "List of module:name pairs to rename imports (e.g. 'PIL:pillow')"
         }
       },
       "additionalProperties": false

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "tach"
-version = "0.32.2"
+version = "0.33.0"
 authors = [
     { name = "Caelean Barnes", email = "caeleanb@gmail.com" },
     { name = "Evan Doyle", email = "evanmdoyle@gmail.com" },

python/tests/example/many_features/pyproject.toml

@@ -2,7 +2,6 @@
 name = "many_features"
 version = "0.0.1"
 dependencies = [
-    "pyyaml~=6.0",
     "tomli>=1.2.2",
     "tomli-w~=1.0",
     "rich~=13.0",
@@ -14,6 +13,9 @@ dependencies = [
     "importlib_metadata>=6.0; python_version == '3.7'",
 ]
 
+[dependency-groups]
+test_dep_groups = ["pyyaml~=6.0"]
+
 [build-system]
 requires = ["maturin>=1.5,<2.0"]
 build-backend = "maturin"
@@ -22,3 +24,6 @@ build-backend = "maturin"
 python-source = "real_src"
 module-name = "tach.extension"
 features = ["pyo3/extension-module"]
+
+[tool.tach.external]
+include_dependency_groups = ["test_dep_groups"]

src/external/error.rs

@@ -13,4 +13,11 @@ pub enum ParsingError {
     TomlParse(#[from] toml::de::Error),
     #[error("Missing field in TOML: {0}")]
     MissingField(String),
+    #[error("Dependency group '{included}' included from '{from_group}' does not exist")]
+    MissingDependencyGroup {
+        included: String,
+        from_group: String,
+    },
+    #[error("Circular dependency group reference: '{group}' includes itself")]
+    CircularDependencyGroup { group: String },
 }