Add python source files specified in pyproject.toml to sdist

Changelog.md

@@ -19,6 +19,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Fix sdist when `pyproject.toml` isn't in the same dir of `Cargo.toml` in [#1099](https://github.com/PyO3/maturin/pull/1099)
 * Change readme and license paths in `pyproject.toml` to be relative to `pyproject.toml` in [#1100](https://github.com/PyO3/maturin/pull/1100)
   It's technically a **breaking change**, but previously it doesn't work properly.
+* Add python source files specified in pyproject.toml to sdist in [#1102](https://github.com/PyO3/maturin/pull/1102)
 
 ## [0.13.2] - 2022-08-14
 

src/source_distribution.rs

@@ -202,7 +202,7 @@ fn add_crate_to_source_distribution(
                 PathBuf::from("pyproject.toml"),
                 pyproject_toml_path.to_path_buf(),
             ));
-            // Add readme and license files
+            // Add readme, license and python source files
             if let Some(project) = pyproject.project.as_ref() {
                 if let Some(pyproject_toml::ReadMe::RelativePath(readme)) = project.readme.as_ref()
                 {
@@ -215,6 +215,13 @@ fn add_crate_to_source_distribution(
                 {
                     target_source.push((PathBuf::from(license), pyproject_dir.join(license)));
                 }
+                if let Some(python_source) = pyproject.python_source() {
+                    for entry in ignore::Walk::new(pyproject_dir.join(python_source)) {
+                        let path = entry?.into_path();
+                        let relative_path = path.strip_prefix(&pyproject_dir)?;
+                        target_source.push((relative_path.to_path_buf(), path));
+                    }
+                }
             }
         } else {
             bail!(