Add support for specifying cargo manifest path in pyproject.toml

Changelog.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Add support for using [`zig cc`](https://andrewkelley.me/post/zig-cc-powerful-drop-in-replacement-gcc-clang.html) as linker for easier cross compiling and manylinux compliance in [#756](https://github.com/PyO3/maturin/pull/756)
 * Switch from reqwest to ureq to reduce dependencies in [#767](https://github.com/PyO3/maturin/pull/767)
 * Fix missing Python submodule in wheel in [#772](https://github.com/PyO3/maturin/pull/772)
+* Add support for specifying cargo manifest path in pyproject.toml in [#781](https://github.com/PyO3/maturin/pull/781)
 
 ## [0.12.6] - 2021-12-31
 

src/build_options.rs

@@ -47,15 +47,9 @@ pub struct BuildOptions {
     /// Which kind of bindings to use. Possible values are pyo3, rust-cpython, cffi and bin
     #[clap(short, long)]
     pub bindings: Option<String>,
-    #[clap(
-        short = 'm',
-        long = "manifest-path",
-        parse(from_os_str),
-        default_value = "Cargo.toml",
-        name = "PATH"
-    )]
+    #[clap(short = 'm', long = "manifest-path", parse(from_os_str), name = "PATH")]
     /// The path to the Cargo.toml
-    pub manifest_path: PathBuf,
+    pub manifest_path: Option<PathBuf>,
     /// The directory to store the built wheels in. Defaults to a new "wheels"
     /// directory in the project's target directory
     #[clap(short, long, parse(from_os_str))]
@@ -99,7 +93,7 @@ impl Default for BuildOptions {
             platform_tag: None,
             interpreter: Some(vec![]),
             bindings: None,
-            manifest_path: PathBuf::from("Cargo.toml"),
+            manifest_path: None,
             out: None,
             skip_auditwheel: false,
             zig: false,
@@ -112,28 +106,52 @@ impl Default for BuildOptions {
 }
 
 impl BuildOptions {
+    /// Get cargo manifest file path
+    fn manifest_path(&self) -> Result<PathBuf> {
+        // use command line argument if specified
+        if let Some(path) = &self.manifest_path {
+            return Ok(path.clone());
+        }
+        // check `manifest-path` option in pyproject.toml
+        let current_dir = env::current_dir()
+            .context("Failed to detect current directory ಠ_ಠ")?
+            .canonicalize()?;
+        let pyproject = PyProjectToml::new(&current_dir).context("pyproject.toml is invalid")?;
+        if let Some(path) = pyproject.manifest_path() {
+            println!("🔗 Found cargo manifest path in pyproject.toml");
+            // pyproject.toml must be placed at top directory
+            let manifest_dir = path
+                .parent()
+                .context("missing parent directory")?
+                .canonicalize()?;
+            if !manifest_dir.starts_with(&current_dir) {
+                bail!("Cargo.toml can not be placed outside of the directory containing pyproject.toml");
+            }
+            return Ok(path.to_path_buf());
+        }
+        // check Cargo.toml in current directory
+        let path = PathBuf::from("Cargo.toml");
+        if path.exists() {
+            Ok(path)
+        } else {
+            Err(format_err!(
+                "Can't find {} (in {})",
+                path.display(),
+                current_dir.display()
+            ))
+        }
+    }
     /// Tries to fill the missing metadata for a BuildContext by querying cargo and python
     pub fn into_build_context(
         self,
         release: bool,
         strip: bool,
         editable: bool,
     ) -> Result<BuildContext> {
-        let manifest_file = &self.manifest_path;
-        if !manifest_file.exists() {
-            let current_dir =
-                env::current_dir().context("Failed to detect current directory ಠ_ಠ")?;
-            bail!(
-                "Can't find {} (in {})",
-                self.manifest_path.display(),
-                current_dir.display()
-            );
-        }
-
+        let manifest_file = self.manifest_path()?;
         if !manifest_file.is_file() {
             bail!(
-                "{} (resolved to {}) is not the path to a Cargo.toml",
-                self.manifest_path.display(),
+                "{} is not the path to a Cargo.toml",
                 manifest_file.display()
             );
         }
@@ -195,7 +213,7 @@ impl BuildOptions {
         let cargo_metadata_extra_args = extract_cargo_metadata_args(&cargo_extra_args)?;
 
         let result = MetadataCommand::new()
-            .manifest_path(&self.manifest_path)
+            .manifest_path(&manifest_file)
             .other_options(cargo_metadata_extra_args)
             .exec();
 
@@ -318,7 +336,7 @@ impl BuildOptions {
             metadata21,
             crate_name: crate_name.to_string(),
             module_name,
-            manifest_path: self.manifest_path,
+            manifest_path: manifest_file,
             out: wheel_dir,
             release,
             strip,

src/develop.rs

@@ -32,7 +32,7 @@ pub fn develop(
         platform_tag: Some(PlatformTag::Linux),
         interpreter: Some(vec![python.clone()]),
         bindings,
-        manifest_path: manifest_file.to_path_buf(),
+        manifest_path: Some(manifest_file.to_path_buf()),
         out: Some(wheel_dir.path().to_path_buf()),
         skip_auditwheel: false,
         zig: false,

src/main.rs

@@ -299,7 +299,7 @@ fn pep517(subcommand: Pep517Command) -> Result<()> {
             manifest_path,
         } => {
             let build_options = BuildOptions {
-                manifest_path,
+                manifest_path: Some(manifest_path),
                 out: Some(sdist_directory),
                 ..Default::default()
             };
@@ -405,7 +405,7 @@ fn run() -> Result<()> {
         }
         Opt::SDist { manifest_path, out } => {
             let build_options = BuildOptions {
-                manifest_path,
+                manifest_path: Some(manifest_path),
                 out,
                 ..Default::default()
             };

src/pyproject_toml.rs

@@ -3,7 +3,7 @@ use anyhow::{format_err, Context, Result};
 use pyproject_toml::PyProjectToml as ProjectToml;
 use serde::{Deserialize, Serialize};
 use std::fs;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 /// The `[tool]` section of a pyproject.toml
 #[derive(Serialize, Deserialize, Debug, Clone)]
@@ -16,6 +16,7 @@ pub struct Tool {
 #[derive(Serialize, Deserialize, Debug, Clone)]
 #[serde(rename_all = "kebab-case")]
 pub struct ToolMaturin {
+    manifest_path: Option<PathBuf>,
     sdist_include: Option<Vec<String>>,
     bindings: Option<String>,
     cargo_extra_args: Option<String>,
@@ -119,6 +120,16 @@ impl PyProjectToml {
             .unwrap_or_default()
     }
 
+    /// Returns the value of `[tool.maturin.manifest-path]` in pyproject.toml
+    pub fn manifest_path(&self) -> Option<&Path> {
+        self.tool
+            .as_ref()?
+            .maturin
+            .as_ref()?
+            .manifest_path
+            .as_deref()
+    }
+
     /// Having a pyproject.toml without a version constraint is a bad idea
     /// because at some point we'll have to do breaking changes and then source
     /// distributions would break

tests/common/integration.rs

@@ -171,7 +171,6 @@ fn create_conda_env(name: &str, major: usize, minor: usize) {
 
 #[cfg(target_os = "windows")]
 pub fn test_integration_conda(package: impl AsRef<Path>, bindings: Option<String>) -> Result<()> {
-    use std::env;
     use std::process::Stdio;
 
     let package_string = package.as_ref().join("Cargo.toml").display().to_string();

tests/common/other.rs

@@ -116,7 +116,7 @@ pub fn test_source_distribution(
     let sdist_directory = Path::new("test-crates").join("wheels").join(unique_name);
 
     let build_options = BuildOptions {
-        manifest_path,
+        manifest_path: Some(manifest_path),
         out: Some(sdist_directory),
         cargo_extra_args: vec![
             "--quiet".to_string(),