Add missing runfiles to pyo3 targets (#3917)

Relates to #3902 but I
think it's still correct to collect all runfiles for the underlying
library target.

Author: UebelAndre

extensions/pyo3/private/pyo3.bzl

@@ -153,7 +153,7 @@ def _py_pyo3_library_impl(ctx):
             runfiles = ctx.runfiles(
                 files = [ext],
                 transitive_files = depset(files, transitive = [crate_info.data]),
-            ),
+            ).merge(ctx.attr.extension[DefaultInfo].default_runfiles),
         ),
         PyInfo(
             imports = _get_imports(ctx, ctx.attr.imports),

extensions/pyo3/test/module_prefix_imports/bar.rs

@@ -10,4 +10,3 @@ fn bar(m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_function(wrap_pyfunction!(thing, m)?)?;
     Ok(())
 }
-

extensions/pyo3/test/runfiles/BUILD.bazel

@@ -1,12 +1,24 @@
 load("@rules_python//python:defs.bzl", "py_test")
+load("@rules_rust//rust:defs.bzl", "rust_library")
 load("//:defs.bzl", "pyo3_extension")
 
+rust_library(
+    name = "reader_helper",
+    srcs = ["reader_helper.rs"],
+    data = ["helper_data.txt"],
+    edition = "2021",
+    deps = ["@rules_rust//tools/runfiles"],
+)
+
 pyo3_extension(
     name = "reader",
     srcs = ["reader.rs"],
     data = ["data.txt"],
     edition = "2021",
-    deps = ["@rules_rust//tools/runfiles"],
+    deps = [
+        ":reader_helper",
+        "@rules_rust//tools/runfiles",
+    ],
 )
 
 py_test(

extensions/pyo3/test/runfiles/helper_data.txt

@@ -0,0 +1 @@
+Transitive helper data from rust_library.

extensions/pyo3/test/runfiles/reader.rs

@@ -2,23 +2,28 @@
 
 use pyo3::exceptions::PyFileNotFoundError;
 use pyo3::prelude::*;
+use reader_helper::read_helper_data;
 use runfiles::{rlocation, Runfiles};
 
-/// Formats the sum of two numbers as string.
-#[pyfunction]
-fn read_data() -> PyResult<String> {
-    let r = Runfiles::create().unwrap();
-    let path = rlocation!(r, "rules_rust_pyo3/test/runfiles/data.txt").unwrap();
-
-    std::fs::read_to_string(path).map_err(PyFileNotFoundError::new_err)
-}
-
 /// A Python module implemented in Rust. The name of this function must match
 /// the `lib.name` setting in the `Cargo.toml`, else Python will not be able to
 /// import the module.
 #[pymodule]
-fn reader(m: &Bound<'_, PyModule>) -> PyResult<()> {
-    m.add_function(wrap_pyfunction!(read_data, m)?)?;
+mod reader {
+
+    use super::*;
+
+    /// Formats the sum of two numbers as string.
+    #[pyfunction]
+    fn read_data() -> PyResult<String> {
+        let r = Runfiles::create().unwrap();
+        let path = rlocation!(r, "rules_rust_pyo3/test/runfiles/data.txt").unwrap();
+
+        std::fs::read_to_string(path).map_err(PyFileNotFoundError::new_err)
+    }
 
-    Ok(())
+    #[pyfunction]
+    fn read_transitive_data() -> PyResult<String> {
+        read_helper_data().map_err(PyFileNotFoundError::new_err)
+    }
 }

extensions/pyo3/test/runfiles/reader_helper.rs

@@ -0,0 +1,15 @@
+//! A helper crate for loading transitive runfile data.
+
+use runfiles::{rlocation, Runfiles};
+
+pub fn read_helper_data() -> std::io::Result<String> {
+    let runfiles = Runfiles::create().map_err(std::io::Error::other)?;
+    let path =
+        rlocation!(runfiles, "rules_rust_pyo3/test/runfiles/helper_data.txt").ok_or_else(|| {
+            std::io::Error::new(
+                std::io::ErrorKind::NotFound,
+                "helper runfile path could not be resolved",
+            )
+        })?;
+    std::fs::read_to_string(path)
+}

extensions/pyo3/test/runfiles/reader_test.py

@@ -50,6 +50,13 @@ def test_transitive_runfiles_access(self) -> None:
             "La-Li-Lu-Le-Lo", data_file.read_text(encoding="utf-8").strip()
         )
 
+    def test_rust_library_data_via_pyo3(self) -> None:
+        """A test which reads transitive rust_library data through pyo3."""
+
+        result = reader.read_transitive_data()
+        self.assertIsInstance(result, str)
+        self.assertEqual("Transitive helper data from rust_library.", result.strip())
+
 
 if __name__ == "__main__":
     unittest.main()