Add support for Cargo workspace inheritance

https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#inheriting-a-dependency-from-a-workspace

test-crates/workspace-inheritance/Cargo.toml

@@ -0,0 +1,8 @@
+[workspace]
+members = [
+  "generic_lib",
+  "python"
+]
+
+[workspace.dependencies]
+generic_lib = { path = "generic_lib" }

test-crates/workspace-inheritance/generic_lib/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "generic_lib"
+version = "0.1.0"
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

test-crates/workspace-inheritance/generic_lib/src/lib.rs

@@ -0,0 +1,3 @@
+pub fn foo() -> &'static str {
+    "foo"
+}

test-crates/workspace-inheritance/python/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "workspace_with_path_dep"
+version = "0.1.0"
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+pyo3 = { version = "0.16.5", features = ["extension-module"] }
+generic_lib.workspace = true

test-crates/workspace-inheritance/python/pyproject.toml

@@ -0,0 +1,3 @@
+[build-system]
+requires = ["maturin>=0.13,<0.14"]
+build-backend = "maturin"

test-crates/workspace-inheritance/python/src/lib.rs

@@ -0,0 +1,14 @@
+use pyo3::prelude::*;
+
+/// Formats the sum of two numbers as string.
+#[pyfunction]
+fn sum_as_string(a: usize, b: usize) -> PyResult<String> {
+    Ok((a + b).to_string())
+}
+
+/// A Python module implemented in Rust.
+#[pymodule]
+fn workspace_with_path_dep(_py: Python, m: &PyModule) -> PyResult<()> {
+    m.add_function(wrap_pyfunction!(sum_as_string, m)?)?;
+    Ok(())
+}

tests/run.rs

@@ -293,6 +293,22 @@ fn workspace_with_path_dep_sdist() {
     ))
 }
 
+#[test]
+fn workspace_inheritance_sdist() {
+    handle_result(other::test_source_distribution(
+        "test-crates/workspace-inheritance/python",
+        vec![
+            "workspace-inheritance-0.1.0/local_dependencies/generic_lib/Cargo.toml",
+            "workspace-inheritance-0.1.0/local_dependencies/generic_lib/src/lib.rs",
+            "workspace-inheritance-0.1.0/Cargo.toml",
+            "workspace-inheritance-0.1.0/pyproject.toml",
+            "workspace-inheritance-0.1.0/src/lib.rs",
+            "workspace-inheritance-0.1.0/PKG-INFO",
+        ],
+        "workspace_inheritance_sdist",
+    ))
+}
+
 #[test]
 fn abi3_python_interpreter_args() {
     handle_result(other::abi3_python_interpreter_args());