Tweak language for build backend validation errors

crates/uv-build-backend/src/lib.rs

@@ -32,9 +32,9 @@ use crate::settings::ModuleName;
 pub enum Error {
     #[error(transparent)]
     Io(#[from] io::Error),
-    #[error("Invalid pyproject.toml")]
-    Toml(#[from] toml::de::Error),
-    #[error("Invalid pyproject.toml")]
+    #[error("Invalid metadata format in: {}", _0.user_display())]
+    Toml(PathBuf, #[source] toml::de::Error),
+    #[error("Invalid project metadata")]
     Validation(#[from] ValidationError),
     #[error("Invalid module name: {0}")]
     InvalidModuleName(String, #[source] IdentifierParseError),

crates/uv-build-backend/src/metadata.rs

@@ -154,8 +154,11 @@ impl PyProjectToml {
         &self.project.version
     }
 
-    pub(crate) fn parse(contents: &str) -> Result<Self, Error> {
-        Ok(toml::from_str(contents)?)
+    pub(crate) fn parse(path: &Path) -> Result<Self, Error> {
+        let contents = fs_err::read_to_string(path)?;
+        let pyproject_toml =
+            toml::from_str(&contents).map_err(|err| Error::Toml(path.to_path_buf(), err))?;
+        Ok(pyproject_toml)
     }
 
     pub(crate) fn readme(&self) -> Option<&Readme> {
@@ -949,7 +952,7 @@ mod tests {
             requires = ["uv_build>=0.4.15,<0.5.0"]
             build-backend = "uv_build"
         "#;
-        let pyproject_toml = PyProjectToml::parse(contents).unwrap();
+        let pyproject_toml: PyProjectToml = toml::from_str(contents).unwrap();
         let temp_dir = TempDir::new().unwrap();
 
         let metadata = pyproject_toml.to_metadata(temp_dir.path()).unwrap();
@@ -1034,7 +1037,7 @@ mod tests {
         "#
         };
 
-        let pyproject_toml = PyProjectToml::parse(contents).unwrap();
+        let pyproject_toml: PyProjectToml = toml::from_str(contents).unwrap();
         let metadata = pyproject_toml.to_metadata(temp_dir.path()).unwrap();
 
         assert_snapshot!(metadata.core_metadata_format(), @r###"
@@ -1128,7 +1131,7 @@ mod tests {
         "#
         };
 
-        let pyproject_toml = PyProjectToml::parse(contents).unwrap();
+        let pyproject_toml: PyProjectToml = toml::from_str(contents).unwrap();
         let metadata = pyproject_toml.to_metadata(temp_dir.path()).unwrap();
 
         assert_snapshot!(metadata.core_metadata_format(), @r"
@@ -1220,7 +1223,7 @@ mod tests {
         "#
         };
 
-        let pyproject_toml = PyProjectToml::parse(contents).unwrap();
+        let pyproject_toml: PyProjectToml = toml::from_str(contents).unwrap();
         let metadata = pyproject_toml.to_metadata(temp_dir.path()).unwrap();
 
         assert_snapshot!(metadata.core_metadata_format(), @r###"
@@ -1281,7 +1284,7 @@ mod tests {
     #[test]
     fn build_system_valid() {
         let contents = extend_project("");
-        let pyproject_toml = PyProjectToml::parse(&contents).unwrap();
+        let pyproject_toml: PyProjectToml = toml::from_str(&contents).unwrap();
         assert_snapshot!(
             pyproject_toml.check_build_system("0.4.15+test").join("\n"),
             @""
@@ -1299,7 +1302,7 @@ mod tests {
             requires = ["uv_build"]
             build-backend = "uv_build"
         "#};
-        let pyproject_toml = PyProjectToml::parse(contents).unwrap();
+        let pyproject_toml: PyProjectToml = toml::from_str(contents).unwrap();
         assert_snapshot!(
             pyproject_toml.check_build_system("0.4.15+test").join("\n"),
             @r###"`build_system.requires = ["uv_build"]` is missing an upper bound on the `uv_build` version such as `<0.5`. Without bounding the `uv_build` version, the source distribution will break when a future, breaking version of `uv_build` is released."###
@@ -1317,7 +1320,7 @@ mod tests {
             requires = ["uv_build>=0.4.15,<0.5.0", "wheel"]
             build-backend = "uv_build"
         "#};
-        let pyproject_toml = PyProjectToml::parse(contents).unwrap();
+        let pyproject_toml: PyProjectToml = toml::from_str(contents).unwrap();
         assert_snapshot!(
             pyproject_toml.check_build_system("0.4.15+test").join("\n"),
             @"Expected a single uv requirement in `build-system.requires`, found ``"
@@ -1335,7 +1338,7 @@ mod tests {
             requires = ["setuptools"]
             build-backend = "uv_build"
         "#};
-        let pyproject_toml = PyProjectToml::parse(contents).unwrap();
+        let pyproject_toml: PyProjectToml = toml::from_str(contents).unwrap();
         assert_snapshot!(
             pyproject_toml.check_build_system("0.4.15+test").join("\n"),
             @"Expected a single uv requirement in `build-system.requires`, found ``"
@@ -1353,7 +1356,7 @@ mod tests {
             requires = ["uv_build>=0.4.15,<0.5.0"]
             build-backend = "setuptools"
         "#};
-        let pyproject_toml = PyProjectToml::parse(contents).unwrap();
+        let pyproject_toml: PyProjectToml = toml::from_str(contents).unwrap();
         assert_snapshot!(
             pyproject_toml.check_build_system("0.4.15+test").join("\n"),
             @r###"The value for `build_system.build-backend` should be `"uv_build"`, not `"setuptools"`"###
@@ -1364,7 +1367,7 @@ mod tests {
     fn minimal() {
         let contents = extend_project("");
 
-        let metadata = PyProjectToml::parse(&contents)
+        let metadata = toml::from_str::<PyProjectToml>(&contents)
             .unwrap()
             .to_metadata(Path::new("/do/not/read"))
             .unwrap();
@@ -1383,15 +1386,14 @@ mod tests {
         "#
         });
 
-        let err = PyProjectToml::parse(&contents).unwrap_err();
-        assert_snapshot!(format_err(err), @r###"
-        Invalid pyproject.toml
-          Caused by: TOML parse error at line 4, column 10
+        let err = toml::from_str::<PyProjectToml>(&contents).unwrap_err();
+        assert_snapshot!(format_err(err), @r#"
+        TOML parse error at line 4, column 10
           |
         4 | readme = { path = "Readme.md" }
           |          ^^^^^^^^^^^^^^^^^^^^^^
         data did not match any variant of untagged enum Readme
-        "###);
+        "#);
     }
 
     #[test]
@@ -1401,7 +1403,7 @@ mod tests {
         "#
         });
 
-        let err = PyProjectToml::parse(&contents)
+        let err = toml::from_str::<PyProjectToml>(&contents)
             .unwrap()
             .to_metadata(Path::new("/do/not/read"))
             .unwrap_err();
@@ -1423,14 +1425,14 @@ mod tests {
         "#
         });
 
-        let err = PyProjectToml::parse(&contents)
+        let err = toml::from_str::<PyProjectToml>(&contents)
             .unwrap()
             .to_metadata(Path::new("/do/not/read"))
             .unwrap_err();
-        assert_snapshot!(format_err(err), @r###"
-        Invalid pyproject.toml
+        assert_snapshot!(format_err(err), @r"
+        Invalid project metadata
           Caused by: `project.description` must be a single line
-        "###);
+        ");
     }
 
     #[test]
@@ -1441,14 +1443,14 @@ mod tests {
         "#
         });
 
-        let err = PyProjectToml::parse(&contents)
+        let err = toml::from_str::<PyProjectToml>(&contents)
             .unwrap()
             .to_metadata(Path::new("/do/not/read"))
             .unwrap_err();
-        assert_snapshot!(format_err(err), @r###"
-        Invalid pyproject.toml
+        assert_snapshot!(format_err(err), @r"
+        Invalid project metadata
           Caused by: When `project.license-files` is defined, `project.license` must be an SPDX expression string
-        "###);
+        ");
     }
 
     #[test]
@@ -1457,7 +1459,7 @@ mod tests {
             license = "MIT OR Apache-2.0"
         "#
         });
-        let metadata = PyProjectToml::parse(&contents)
+        let metadata = toml::from_str::<PyProjectToml>(&contents)
             .unwrap()
             .to_metadata(Path::new("/do/not/read"))
             .unwrap();
@@ -1475,13 +1477,13 @@ mod tests {
             license = "MIT XOR Apache-2"
         "#
         });
-        let err = PyProjectToml::parse(&contents)
+        let err = toml::from_str::<PyProjectToml>(&contents)
             .unwrap()
             .to_metadata(Path::new("/do/not/read"))
             .unwrap_err();
         // TODO(konsti): We mess up the indentation in the error.
         assert_snapshot!(format_err(err), @r"
-        Invalid pyproject.toml
+        Invalid project metadata
           Caused by: `project.license` is not a valid SPDX expression: MIT XOR Apache-2
           Caused by: MIT XOR Apache-2
             ^^^ unknown term
@@ -1495,18 +1497,18 @@ mod tests {
         "#
         });
 
-        let err = PyProjectToml::parse(&contents)
+        let err = toml::from_str::<PyProjectToml>(&contents)
             .unwrap()
             .to_metadata(Path::new("/do/not/read"))
             .unwrap_err();
-        assert_snapshot!(format_err(err), @r###"
-        Invalid pyproject.toml
+        assert_snapshot!(format_err(err), @r"
+        Invalid project metadata
           Caused by: Dynamic metadata is not supported
-        "###);
+        ");
     }
 
     fn script_error(contents: &str) -> String {
-        let err = PyProjectToml::parse(contents)
+        let err = toml::from_str::<PyProjectToml>(contents)
             .unwrap()
             .to_entry_points()
             .unwrap_err();

crates/uv-build-backend/src/source_dist.rs

@@ -26,8 +26,7 @@ pub fn build_source_dist(
     uv_version: &str,
     show_warnings: bool,
 ) -> Result<SourceDistFilename, Error> {
-    let contents = fs_err::read_to_string(source_tree.join("pyproject.toml"))?;
-    let pyproject_toml = PyProjectToml::parse(&contents)?;
+    let pyproject_toml = PyProjectToml::parse(&source_tree.join("pyproject.toml"))?;
     let filename = SourceDistFilename {
         name: pyproject_toml.name().clone(),
         version: pyproject_toml.version().clone(),
@@ -45,8 +44,7 @@ pub fn list_source_dist(
     uv_version: &str,
     show_warnings: bool,
 ) -> Result<(SourceDistFilename, FileList), Error> {
-    let contents = fs_err::read_to_string(source_tree.join("pyproject.toml"))?;
-    let pyproject_toml = PyProjectToml::parse(&contents)?;
+    let pyproject_toml = PyProjectToml::parse(&source_tree.join("pyproject.toml"))?;
     let filename = SourceDistFilename {
         name: pyproject_toml.name().clone(),
         version: pyproject_toml.version().clone(),
@@ -188,8 +186,7 @@ fn write_source_dist(
     uv_version: &str,
     show_warnings: bool,
 ) -> Result<SourceDistFilename, Error> {
-    let contents = fs_err::read_to_string(source_tree.join("pyproject.toml"))?;
-    let pyproject_toml = PyProjectToml::parse(&contents)?;
+    let pyproject_toml = PyProjectToml::parse(&source_tree.join("pyproject.toml"))?;
     for warning in pyproject_toml.check_build_system(uv_version) {
         warn_user_once!("{warning}");
     }

crates/uv-build-backend/src/wheel.rs

@@ -31,8 +31,7 @@ pub fn build_wheel(
     uv_version: &str,
     show_warnings: bool,
 ) -> Result<WheelFilename, Error> {
-    let contents = fs_err::read_to_string(source_tree.join("pyproject.toml"))?;
-    let pyproject_toml = PyProjectToml::parse(&contents)?;
+    let pyproject_toml = PyProjectToml::parse(&source_tree.join("pyproject.toml"))?;
     for warning in pyproject_toml.check_build_system(uv_version) {
         warn_user_once!("{warning}");
     }
@@ -71,8 +70,7 @@ pub fn list_wheel(
     uv_version: &str,
     show_warnings: bool,
 ) -> Result<(WheelFilename, FileList), Error> {
-    let contents = fs_err::read_to_string(source_tree.join("pyproject.toml"))?;
-    let pyproject_toml = PyProjectToml::parse(&contents)?;
+    let pyproject_toml = PyProjectToml::parse(&source_tree.join("pyproject.toml"))?;
     for warning in pyproject_toml.check_build_system(uv_version) {
         warn_user_once!("{warning}");
     }
@@ -273,8 +271,7 @@ pub fn build_editable(
     uv_version: &str,
     show_warnings: bool,
 ) -> Result<WheelFilename, Error> {
-    let contents = fs_err::read_to_string(source_tree.join("pyproject.toml"))?;
-    let pyproject_toml = PyProjectToml::parse(&contents)?;
+    let pyproject_toml = PyProjectToml::parse(&source_tree.join("pyproject.toml"))?;
     for warning in pyproject_toml.check_build_system(uv_version) {
         warn_user_once!("{warning}");
     }
@@ -335,8 +332,7 @@ pub fn metadata(
     metadata_directory: &Path,
     uv_version: &str,
 ) -> Result<String, Error> {
-    let contents = fs_err::read_to_string(source_tree.join("pyproject.toml"))?;
-    let pyproject_toml = PyProjectToml::parse(&contents)?;
+    let pyproject_toml = PyProjectToml::parse(&source_tree.join("pyproject.toml"))?;
     for warning in pyproject_toml.check_build_system(uv_version) {
         warn_user_once!("{warning}");
     }

crates/uv/tests/it/build_backend.rs

@@ -792,15 +792,15 @@ fn license_glob_without_matches_errors() -> Result<()> {
         .build_backend()
         .arg("build-wheel")
         .arg(context.temp_dir.path())
-        .current_dir(project.path()), @r###"
+        .current_dir(project.path()), @r"
     success: false
     exit_code: 2
     ----- stdout -----
 
     ----- stderr -----
-    error: Invalid pyproject.toml
+    error: Invalid project metadata
       Caused by: `project.license-files` glob `abc` did not match any files
-    "###);
+    ");
 
     Ok(())
 }
@@ -835,15 +835,15 @@ fn license_file_must_be_utf8() -> Result<()> {
         .build_backend()
         .arg("build-wheel")
         .arg(context.temp_dir.path())
-        .current_dir(project.path()), @r###"
+        .current_dir(project.path()), @r"
     success: false
     exit_code: 2
     ----- stdout -----
 
     ----- stderr -----
-    error: Invalid pyproject.toml
+    error: Invalid project metadata
       Caused by: License file `LICENSE.bin` must be UTF-8 encoded
-    "###);
+    ");
 
     Ok(())
 }
@@ -1185,3 +1185,40 @@ fn warn_on_redundant_module_names() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn invalid_pyproject_toml() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    context
+        .temp_dir
+        .child("child")
+        .child("pyproject.toml")
+        .write_str(indoc! {r#"
+        [project]
+        name = 1
+        version = "1.0.0"
+
+        [build-system]
+        requires = ["uv_build>=0.9,<10000"]
+        build-backend = "uv_build"
+    "#})?;
+
+    uv_snapshot!(context.filters(), context.build().arg("child"), @r"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    Building source distribution (uv build backend)...
+      × Failed to build `[TEMP_DIR]/child`
+      ├─▶ Invalid metadata format in: child/pyproject.toml
+      ╰─▶ TOML parse error at line 2, column 8
+            |
+          2 | name = 1
+            |        ^
+          invalid type: integer `1`, expected a string
+    ");
+
+    Ok(())
+}