Recommend --native-tls on SSL errors (#10605)

## Summary

Closes https://github.com/astral-sh/uv/issues/10574.

## Test Plan

```
❯ SSL_CERT_FILE=a cargo run pip install flask -n
   Compiling uv v0.5.18 (/Users/crmarsh/workspace/uv/crates/uv)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 8.33s
     Running `target/debug/uv pip install flask -n`
⠦ Resolving dependencies...                                                                                                                                                                                                                     × Failed to fetch: `https://pypi.org/simple/flask/`
  ├─▶ Request failed after 3 retries
  ├─▶ error sending request for url (https://pypi.org/simple/flask/)
  ├─▶ client error (Connect)
  ╰─▶ invalid peer certificate: UnknownIssuer
  help: Consider enabling native TLS support via the `--native-tls` command-line flag
```

crates/uv-client/src/error.rs

@@ -51,6 +51,11 @@ impl Error {
         matches!(err.kind(), std::io::ErrorKind::NotFound)
     }
 
+    /// Returns `true` if the error is due to an SSL error.
+    pub fn is_ssl(&self) -> bool {
+        matches!(&*self.kind, ErrorKind::WrappedReqwestError(.., err) if err.is_ssl())
+    }
+
     /// Returns `true` if the error is due to the server not supporting HTTP range requests.
     pub fn is_http_range_requests_unsupported(&self) -> bool {
         match &*self.kind {
@@ -260,13 +265,9 @@ impl ErrorKind {
 pub struct WrappedReqwestError(reqwest_middleware::Error);
 
 impl WrappedReqwestError {
-    /// Check if the error chain contains a reqwest error that looks like this:
-    /// * error sending request for url (...)
-    /// * client error (Connect)
-    /// * dns error: failed to lookup address information: Name or service not known
-    /// * failed to lookup address information: Name or service not known
-    fn is_likely_offline(&self) -> bool {
-        let reqwest_err = match &self.0 {
+    /// Return the inner [`reqwest::Error`] from the error chain, if it exists.
+    fn inner(&self) -> Option<&reqwest::Error> {
+        match &self.0 {
             reqwest_middleware::Error::Reqwest(err) => Some(err),
             reqwest_middleware::Error::Middleware(err) => err.chain().find_map(|err| {
                 if let Some(err) = err.downcast_ref::<reqwest::Error>() {
@@ -279,9 +280,16 @@ impl WrappedReqwestError {
                     None
                 }
             }),
-        };
+        }
+    }
 
-        if let Some(reqwest_err) = reqwest_err {
+    /// Check if the error chain contains a `reqwest` error that looks like this:
+    /// * error sending request for url (...)
+    /// * client error (Connect)
+    /// * dns error: failed to lookup address information: Name or service not known
+    /// * failed to lookup address information: Name or service not known
+    fn is_likely_offline(&self) -> bool {
+        if let Some(reqwest_err) = self.inner() {
             if !reqwest_err.is_connect() {
                 return false;
             }
@@ -297,6 +305,26 @@ impl WrappedReqwestError {
         }
         false
     }
+
+    /// Check if the error chain contains a `reqwest` error that looks like this:
+    /// * invalid peer certificate: `UnknownIssuer`
+    fn is_ssl(&self) -> bool {
+        if let Some(reqwest_err) = self.inner() {
+            if !reqwest_err.is_connect() {
+                return false;
+            }
+            // Self is "error sending request for url", the first source is "error trying to connect",
+            // the second source is "dns error". We have to check for the string because hyper errors
+            // are opaque.
+            if std::error::Error::source(&reqwest_err)
+                .and_then(|err| err.source())
+                .is_some_and(|err| err.to_string().starts_with("invalid peer certificate: "))
+            {
+                return true;
+            }
+        }
+        false
+    }
 }
 
 impl From<reqwest::Error> for WrappedReqwestError {

crates/uv/src/commands/diagnostics.rs

@@ -34,26 +34,37 @@ static SUGGESTIONS: LazyLock<FxHashMap<PackageName, PackageName>> = LazyLock::ne
 pub(crate) struct OperationDiagnostic {
     /// The hint to display to the user upon resolution failure.
     pub(crate) hint: Option<String>,
+    /// Whether native TLS is enabled.
+    pub(crate) native_tls: bool,
     /// The context to display to the user upon resolution failure.
     pub(crate) context: Option<&'static str>,
 }
 
 impl OperationDiagnostic {
+    /// Create an [`OperationDiagnostic`] with the given native TLS setting.
+    #[must_use]
+    pub(crate) fn native_tls(native_tls: bool) -> Self {
+        Self {
+            native_tls,
+            ..Default::default()
+        }
+    }
+
     /// Set the hint to display to the user upon resolution failure.
     #[must_use]
-    pub(crate) fn with_hint(hint: String) -> Self {
+    pub(crate) fn with_hint(self, hint: String) -> Self {
         Self {
             hint: Some(hint),
-            ..Default::default()
+            ..self
         }
     }
 
     /// Set the context to display to the user upon resolution failure.
     #[must_use]
-    pub(crate) fn with_context(context: &'static str) -> Self {
+    pub(crate) fn with_context(self, context: &'static str) -> Self {
         Self {
             context: Some(context),
-            ..Default::default()
+            ..self
         }
     }
 
@@ -106,6 +117,12 @@ impl OperationDiagnostic {
                     Some(pip::operations::Error::Requirements(err))
                 }
             }
+            pip::operations::Error::Resolve(uv_resolver::ResolveError::Client(err))
+                if !self.native_tls && err.is_ssl() =>
+            {
+                native_tls_hint(err);
+                None
+            }
             err => Some(err),
         }
     }
@@ -236,6 +253,41 @@ pub(crate) fn no_solution_hint(err: uv_resolver::NoSolutionError, help: String)
     anstream::eprint!("{report:?}");
 }
 
+/// Render a [`uv_resolver::NoSolutionError`] with a help message.
+pub(crate) fn native_tls_hint(err: uv_client::Error) {
+    #[derive(Debug, miette::Diagnostic)]
+    #[diagnostic()]
+    struct Error {
+        /// The underlying error.
+        err: uv_client::Error,
+
+        /// The help message to display.
+        #[help]
+        help: String,
+    }
+
+    impl std::fmt::Display for Error {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            write!(f, "{}", self.err)
+        }
+    }
+
+    impl std::error::Error for Error {
+        fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+            self.err.source()
+        }
+    }
+
+    let report = miette::Report::new(Error {
+        err,
+        help: format!(
+            "Consider enabling use of system TLS certificates with the `{}` command-line flag",
+            "--native-tls".green()
+        ),
+    });
+    anstream::eprint!("{report:?}");
+}
+
 /// Format a [`DerivationChain`] as a human-readable error message.
 fn format_chain(name: &PackageName, version: Option<&Version>, chain: &DerivationChain) -> String {
     /// Format a step in the [`DerivationChain`] as a human-readable error message.

crates/uv/src/commands/pip/compile.rs

@@ -401,7 +401,7 @@ pub(crate) async fn pip_compile(
     {
         Ok(resolution) => resolution,
         Err(err) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }

crates/uv/src/commands/pip/install.rs

@@ -428,7 +428,7 @@ pub(crate) async fn pip_install(
     {
         Ok(graph) => Resolution::from(graph),
         Err(err) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }
@@ -462,7 +462,7 @@ pub(crate) async fn pip_install(
     {
         Ok(_) => {}
         Err(err) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }

crates/uv/src/commands/pip/sync.rs

@@ -373,7 +373,7 @@ pub(crate) async fn pip_sync(
     {
         Ok(resolution) => Resolution::from(resolution),
         Err(err) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }
@@ -407,7 +407,7 @@ pub(crate) async fn pip_sync(
     {
         Ok(_) => {}
         Err(err) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }

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

@@ -632,7 +632,7 @@ pub(crate) async fn add(
                 let _ = snapshot.revert();
             }
             match err {
-                ProjectError::Operation(err) => diagnostics::OperationDiagnostic::with_hint(format!("If you want to add the package regardless of the failed resolution, provide the `{}` flag to skip locking and syncing.", "--frozen".green()))
+                ProjectError::Operation(err) => diagnostics::OperationDiagnostic::native_tls(native_tls).with_hint(format!("If you want to add the package regardless of the failed resolution, provide the `{}` flag to skip locking and syncing.", "--frozen".green()))
                     .report(err)
                     .map_or(Ok(ExitStatus::Failure), |err| Err(err.into())),
                 err => Err(err.into()),

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

@@ -209,7 +209,7 @@ pub(crate) async fn export(
     {
         Ok(result) => result.into_lock(),
         Err(ProjectError::Operation(err)) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }

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

@@ -193,9 +193,11 @@ pub(crate) async fn lock(
 
             Ok(ExitStatus::Success)
         }
-        Err(ProjectError::Operation(err)) => diagnostics::OperationDiagnostic::default()
-            .report(err)
-            .map_or(Ok(ExitStatus::Failure), |err| Err(err.into())),
+        Err(ProjectError::Operation(err)) => {
+            diagnostics::OperationDiagnostic::native_tls(native_tls)
+                .report(err)
+                .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
+        }
         Err(err) => Err(err.into()),
     }
 }

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

@@ -288,7 +288,7 @@ pub(crate) async fn remove(
     {
         Ok(result) => result.into_lock(),
         Err(ProjectError::Operation(err)) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }
@@ -349,7 +349,7 @@ pub(crate) async fn remove(
     {
         Ok(()) => {}
         Err(ProjectError::Operation(err)) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }

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

@@ -284,7 +284,8 @@ pub(crate) async fn run(
             let environment = match result {
                 Ok(resolution) => resolution,
                 Err(ProjectError::Operation(err)) => {
-                    return diagnostics::OperationDiagnostic::with_context("script")
+                    return diagnostics::OperationDiagnostic::native_tls(native_tls)
+                        .with_context("script")
                         .report(err)
                         .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
                 }
@@ -415,7 +416,8 @@ pub(crate) async fn run(
                 let environment = match result {
                     Ok(resolution) => resolution,
                     Err(ProjectError::Operation(err)) => {
-                        return diagnostics::OperationDiagnostic::with_context("script")
+                        return diagnostics::OperationDiagnostic::native_tls(native_tls)
+                            .with_context("script")
                             .report(err)
                             .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
                     }
@@ -738,7 +740,7 @@ pub(crate) async fn run(
                 {
                     Ok(result) => result,
                     Err(ProjectError::Operation(err)) => {
-                        return diagnostics::OperationDiagnostic::default()
+                        return diagnostics::OperationDiagnostic::native_tls(native_tls)
                             .report(err)
                             .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
                     }
@@ -819,7 +821,7 @@ pub(crate) async fn run(
                 {
                     Ok(()) => {}
                     Err(ProjectError::Operation(err)) => {
-                        return diagnostics::OperationDiagnostic::default()
+                        return diagnostics::OperationDiagnostic::native_tls(native_tls)
                             .report(err)
                             .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
                     }
@@ -972,7 +974,8 @@ pub(crate) async fn run(
                 let environment = match result {
                     Ok(resolution) => resolution,
                     Err(ProjectError::Operation(err)) => {
-                        return diagnostics::OperationDiagnostic::with_context("`--with`")
+                        return diagnostics::OperationDiagnostic::native_tls(native_tls)
+                            .with_context("`--with`")
                             .report(err)
                             .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
                     }

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

@@ -160,7 +160,7 @@ pub(crate) async fn sync(
     {
         Ok(result) => result.into_lock(),
         Err(ProjectError::Operation(err)) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }
@@ -236,7 +236,7 @@ pub(crate) async fn sync(
     {
         Ok(()) => {}
         Err(ProjectError::Operation(err)) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }

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

@@ -162,7 +162,7 @@ pub(crate) async fn tree(
     {
         Ok(result) => result.into_lock(),
         Err(ProjectError::Operation(err)) => {
-            return diagnostics::OperationDiagnostic::default()
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }

crates/uv/src/commands/tool/install.rs

@@ -431,7 +431,7 @@ pub(crate) async fn install(
         {
             Ok(update) => update.into_environment(),
             Err(ProjectError::Operation(err)) => {
-                return diagnostics::OperationDiagnostic::default()
+                return diagnostics::OperationDiagnostic::native_tls(native_tls)
                     .report(err)
                     .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
             }
@@ -491,7 +491,7 @@ pub(crate) async fn install(
                     .await
                     .ok()
                     .flatten() else {
-                        return diagnostics::OperationDiagnostic::default()
+                        return diagnostics::OperationDiagnostic::native_tls(native_tls)
                             .report(err)
                             .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()));
                     };
@@ -520,7 +520,7 @@ pub(crate) async fn install(
                     {
                         Ok(resolution) => resolution,
                         Err(ProjectError::Operation(err)) => {
-                            return diagnostics::OperationDiagnostic::default()
+                            return diagnostics::OperationDiagnostic::native_tls(native_tls)
                                 .report(err)
                                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()));
                         }
@@ -563,7 +563,7 @@ pub(crate) async fn install(
         }) {
             Ok(environment) => environment,
             Err(ProjectError::Operation(err)) => {
-                return diagnostics::OperationDiagnostic::default()
+                return diagnostics::OperationDiagnostic::native_tls(native_tls)
                     .report(err)
                     .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
             }

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

@@ -135,7 +135,8 @@ pub(crate) async fn run(
     let (from, environment) = match result {
         Ok(resolution) => resolution,
         Err(ProjectError::Operation(err)) => {
-            return diagnostics::OperationDiagnostic::with_context("tool")
+            return diagnostics::OperationDiagnostic::native_tls(native_tls)
+                .with_context("tool")
                 .report(err)
                 .map_or(Ok(ExitStatus::Failure), |err| Err(err.into()))
         }