Clarify Python requirement source for script incompatibilities (#7339)

## Summary

Closes #7293.

crates/uv/src/commands/project/mod.rs

@@ -64,13 +64,22 @@ pub(crate) enum ProjectError {
     LockedPlatformIncompatibility(String),
 
     #[error("The requested interpreter resolved to Python {0}, which is incompatible with the project's Python requirement: `{1}`")]
-    RequestedPythonIncompatibility(Version, RequiresPython),
+    RequestedPythonProjectIncompatibility(Version, RequiresPython),
 
-    #[error("The Python request from `{0}` resolved to Python {1}, which incompatible with the project's Python requirement: `{2}`")]
-    DotPythonVersionPythonIncompatibility(String, Version, RequiresPython),
+    #[error("The Python request from `{0}` resolved to Python {1}, which is incompatible with the project's Python requirement: `{2}`")]
+    DotPythonVersionProjectIncompatibility(String, Version, RequiresPython),
 
     #[error("The resolved Python interpreter (Python {0}) is incompatible with the project's Python requirement: `{1}`")]
-    RequiresPythonIncompatibility(Version, RequiresPython),
+    RequiresPythonProjectIncompatibility(Version, RequiresPython),
+
+    #[error("The requested interpreter resolved to Python {0}, which is incompatible with the script's Python requirement: `{1}`")]
+    RequestedPythonScriptIncompatibility(Version, VersionSpecifiers),
+
+    #[error("The Python request from `{0}` resolved to Python {1}, which is incompatible with the script's Python requirement: `{2}`")]
+    DotPythonVersionScriptIncompatibility(String, Version, VersionSpecifiers),
+
+    #[error("The resolved Python interpreter (Python {0}) is incompatible with the script's Python requirement: `{1}`")]
+    RequiresPythonScriptIncompatibility(Version, VersionSpecifiers),
 
     #[error("The requested interpreter resolved to Python {0}, which is incompatible with the project's Python requirement: `{1}`. However, a workspace member (`{member}`) supports Python {3}. To install the workspace member on its own, navigate to `{path}`, then run `{venv}` followed by `{install}`.", member = _2.cyan(), venv = format!("uv venv --python {_0}").green(), install = "uv pip install -e .".green(), path = _4.user_display().cyan() )]
     RequestedMemberIncompatibility(
@@ -81,7 +90,7 @@ pub(crate) enum ProjectError {
         PathBuf,
     ),
 
-    #[error("The Python request from `{0}` resolved to Python {1}, which incompatible with the project's Python requirement: `{2}`. However, a workspace member (`{member}`) supports Python {4}. To install the workspace member on its own, navigate to `{path}`, then run `{venv}` followed by `{install}`.", member = _3.cyan(), venv = format!("uv venv --python {_1}").green(), install = "uv pip install -e .".green(), path = _5.user_display().cyan() )]
+    #[error("The Python request from `{0}` resolved to Python {1}, which is incompatible with the project's Python requirement: `{2}`. However, a workspace member (`{member}`) supports Python {4}. To install the workspace member on its own, navigate to `{path}`, then run `{venv}` followed by `{install}`.", member = _3.cyan(), venv = format!("uv venv --python {_1}").green(), install = "uv pip install -e .".green(), path = _5.user_display().cyan() )]
     DotPythonVersionMemberIncompatibility(
         String,
         Version,
@@ -186,7 +195,7 @@ pub(crate) fn validate_requires_python(
     interpreter: &Interpreter,
     workspace: &Workspace,
     requires_python: &RequiresPython,
-    source: &WorkspacePythonSource,
+    source: &PythonRequestSource,
 ) -> Result<(), ProjectError> {
     if requires_python.contains(interpreter.python_version()) {
         return Ok(());
@@ -206,7 +215,7 @@ pub(crate) fn validate_requires_python(
         };
         if specifiers.contains(interpreter.python_version()) {
             return match source {
-                WorkspacePythonSource::UserRequest => {
+                PythonRequestSource::UserRequest => {
                     Err(ProjectError::RequestedMemberIncompatibility(
                         interpreter.python_version().clone(),
                         requires_python.clone(),
@@ -215,7 +224,7 @@ pub(crate) fn validate_requires_python(
                         member.root().clone(),
                     ))
                 }
-                WorkspacePythonSource::DotPythonVersion(file) => {
+                PythonRequestSource::DotPythonVersion(file) => {
                     Err(ProjectError::DotPythonVersionMemberIncompatibility(
                         file.to_string(),
                         interpreter.python_version().clone(),
@@ -225,7 +234,7 @@ pub(crate) fn validate_requires_python(
                         member.root().clone(),
                     ))
                 }
-                WorkspacePythonSource::RequiresPython => {
+                PythonRequestSource::RequiresPython => {
                     Err(ProjectError::RequiresPythonMemberIncompatibility(
                         interpreter.python_version().clone(),
                         requires_python.clone(),
@@ -239,21 +248,25 @@ pub(crate) fn validate_requires_python(
     }
 
     match source {
-        WorkspacePythonSource::UserRequest => Err(ProjectError::RequestedPythonIncompatibility(
-            interpreter.python_version().clone(),
-            requires_python.clone(),
-        )),
-        WorkspacePythonSource::DotPythonVersion(file) => {
-            Err(ProjectError::DotPythonVersionPythonIncompatibility(
+        PythonRequestSource::UserRequest => {
+            Err(ProjectError::RequestedPythonProjectIncompatibility(
+                interpreter.python_version().clone(),
+                requires_python.clone(),
+            ))
+        }
+        PythonRequestSource::DotPythonVersion(file) => {
+            Err(ProjectError::DotPythonVersionProjectIncompatibility(
                 file.to_string(),
                 interpreter.python_version().clone(),
                 requires_python.clone(),
             ))
         }
-        WorkspacePythonSource::RequiresPython => Err(ProjectError::RequiresPythonIncompatibility(
-            interpreter.python_version().clone(),
-            requires_python.clone(),
-        )),
+        PythonRequestSource::RequiresPython => {
+            Err(ProjectError::RequiresPythonProjectIncompatibility(
+                interpreter.python_version().clone(),
+                requires_python.clone(),
+            ))
+        }
     }
 }
 
@@ -273,7 +286,7 @@ pub(crate) enum FoundInterpreter {
 }
 
 #[derive(Debug, Clone)]
-pub(crate) enum WorkspacePythonSource {
+pub(crate) enum PythonRequestSource {
     /// The request was provided by the user.
     UserRequest,
     /// The request was inferred from a `.python-version` or `.python-versions` file.
@@ -286,7 +299,7 @@ pub(crate) enum WorkspacePythonSource {
 #[derive(Debug, Clone)]
 pub(crate) struct WorkspacePython {
     /// The source of the Python request.
-    source: WorkspacePythonSource,
+    source: PythonRequestSource,
     /// The resolved Python request, computed by considering (1) any explicit request from the user
     /// via `--python`, (2) any implicit request from the user via `.python-version`, and (3) any
     /// `Requires-Python` specifier in the `pyproject.toml`.
@@ -306,14 +319,14 @@ impl WorkspacePython {
 
         let (source, python_request) = if let Some(request) = python_request {
             // (1) Explicit request from user
-            let source = WorkspacePythonSource::UserRequest;
+            let source = PythonRequestSource::UserRequest;
             let request = Some(request);
             (source, request)
         } else if let Some(file) =
             PythonVersionFile::discover(workspace.install_path(), false, false).await?
         {
             // (2) Request from `.python-version`
-            let source = WorkspacePythonSource::DotPythonVersion(file.file_name().to_string());
+            let source = PythonRequestSource::DotPythonVersion(file.file_name().to_string());
             let request = file.into_version();
             (source, request)
         } else {
@@ -324,7 +337,7 @@ impl WorkspacePython {
                 .map(|specifiers| {
                     PythonRequest::Version(VersionRequest::Range(specifiers.clone()))
                 });
-            let source = WorkspacePythonSource::RequiresPython;
+            let source = PythonRequestSource::RequiresPython;
             (source, request)
         };
 

crates/uv/src/commands/project/run.rs

@@ -34,7 +34,9 @@ use crate::commands::pip::loggers::{
 use crate::commands::pip::operations;
 use crate::commands::pip::operations::Modifications;
 use crate::commands::project::environment::CachedEnvironment;
-use crate::commands::project::{validate_requires_python, ProjectError, WorkspacePython};
+use crate::commands::project::{
+    validate_requires_python, ProjectError, PythonRequestSource, WorkspacePython,
+};
 use crate::commands::reporters::PythonDownloadReporter;
 use crate::commands::{project, ExitStatus, SharedState};
 use crate::printer::Printer;
@@ -103,24 +105,27 @@ pub(crate) async fn run(
             script.path.user_display().cyan()
         )?;
 
-        // (1) Explicit request from user
-        let python_request = if let Some(request) = python.as_deref() {
-            Some(PythonRequest::parse(request))
+        let (source, python_request) = if let Some(request) = python.as_deref() {
+            // (1) Explicit request from user
+            let source = PythonRequestSource::UserRequest;
+            let request = Some(PythonRequest::parse(request));
+            (source, request)
+        } else if let Some(file) = PythonVersionFile::discover(&*CWD, false, false).await? {
             // (2) Request from `.python-version`
-        } else if let Some(request) = PythonVersionFile::discover(&*CWD, false, false)
-            .await?
-            .and_then(PythonVersionFile::into_version)
-        {
-            Some(request)
-            // (3) `Requires-Python` in the script
+            let source = PythonRequestSource::DotPythonVersion(file.file_name().to_string());
+            let request = file.into_version();
+            (source, request)
         } else {
-            script
+            // (3) `Requires-Python` in the script
+            let request = script
                 .metadata
                 .requires_python
                 .as_ref()
                 .map(|requires_python| {
                     PythonRequest::Version(VersionRequest::Range(requires_python.clone()))
-                })
+                });
+            let source = PythonRequestSource::RequiresPython;
+            (source, request)
         };
 
         let client_builder = BaseClientBuilder::new()
@@ -141,11 +146,28 @@ pub(crate) async fn run(
 
         if let Some(requires_python) = script.metadata.requires_python.as_ref() {
             if !requires_python.contains(interpreter.python_version()) {
-                warn_user!(
-                    "Python {} does not satisfy the script's `requires-python` specifier: `{}`",
-                    interpreter.python_version(),
-                    requires_python
-                );
+                let err = match source {
+                    PythonRequestSource::UserRequest => {
+                        ProjectError::RequestedPythonScriptIncompatibility(
+                            interpreter.python_version().clone(),
+                            requires_python.clone(),
+                        )
+                    }
+                    PythonRequestSource::DotPythonVersion(file) => {
+                        ProjectError::DotPythonVersionScriptIncompatibility(
+                            file,
+                            interpreter.python_version().clone(),
+                            requires_python.clone(),
+                        )
+                    }
+                    PythonRequestSource::RequiresPython => {
+                        ProjectError::RequiresPythonScriptIncompatibility(
+                            interpreter.python_version().clone(),
+                            requires_python.clone(),
+                        )
+                    }
+                };
+                warn_user!("{err}");
             }
         }
 

crates/uv/tests/lock.rs

@@ -12623,7 +12623,7 @@ fn lock_request_requires_python() -> Result<()> {
 
     ----- stderr -----
     Using Python 3.12.[X] interpreter at: [PYTHON-3.12]
-    error: The Python request from `.python-version` resolved to Python 3.12.[X], which incompatible with the project's Python requirement: `>=3.8, <=3.10`
+    error: The Python request from `.python-version` resolved to Python 3.12.[X], which is incompatible with the project's Python requirement: `>=3.8, <=3.10`
     "###);
 
     Ok(())

crates/uv/tests/run.rs

@@ -418,7 +418,7 @@ fn run_pep723_script_requires_python() -> Result<()> {
 
     ----- stderr -----
     Reading inline script metadata from: main.py
-    warning: Python 3.8.[X] does not satisfy the script's `requires-python` specifier: `>=3.11`
+    warning: The Python request from `.python-version` resolved to Python 3.8.[X], which is incompatible with the script's Python requirement: `>=3.11`
     Resolved 1 package in [TIME]
     Prepared 1 package in [TIME]
     Installed 1 package in [TIME]
@@ -1774,7 +1774,7 @@ fn run_isolated_incompatible_python() -> Result<()> {
 
     ----- stderr -----
     Using Python 3.8.[X] interpreter at: [PYTHON-3.8]
-    error: The Python request from `.python-version` resolved to Python 3.8.[X], which incompatible with the project's Python requirement: `>=3.12`
+    error: The Python request from `.python-version` resolved to Python 3.8.[X], which is incompatible with the project's Python requirement: `>=3.12`
     "###);
 
     // ...even if `--isolated` is provided.
@@ -1784,7 +1784,7 @@ fn run_isolated_incompatible_python() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    error: The Python request from `.python-version` resolved to Python 3.8.[X], which incompatible with the project's Python requirement: `>=3.12`
+    error: The Python request from `.python-version` resolved to Python 3.8.[X], which is incompatible with the project's Python requirement: `>=3.12`
     "###);
 
     Ok(())