fix: unsupported protocol error on old macos version

fix #11726

Author: bebecue

src/cargo/sources/registry/http_remote.rs

@@ -14,7 +14,7 @@ use anyhow::Context;
 use cargo_util::paths;
 use curl::easy::{HttpVersion, List};
 use curl::multi::{EasyHandle, Multi};
-use log::{debug, trace};
+use log::{debug, trace, warn};
 use std::cell::RefCell;
 use std::collections::{HashMap, HashSet};
 use std::fs::{self, File};
@@ -391,6 +391,25 @@ impl<'cfg> HttpRegistry<'cfg> {
     }
 }
 
+// copied from src/cargo/core/package.rs to keep change minimal
+//
+// When dynamically linked against libcurl, we want to ignore some failures
+// when using old versions that don't support certain features.
+macro_rules! try_old_curl {
+    ($e:expr, $msg:expr) => {
+        let result = $e;
+        if cfg!(target_os = "macos") {
+            if let Err(e) = result {
+                warn!("ignoring libcurl {} error: {}", $msg, e);
+            }
+        } else {
+            result.with_context(|| {
+                anyhow::format_err!("failed to enable {}, is curl not built right?", $msg)
+            })?;
+        }
+    };
+}
+
 impl<'cfg> RegistryData for HttpRegistry<'cfg> {
     fn prepare(&self) -> CargoResult<()> {
         Ok(())
@@ -553,7 +572,7 @@ impl<'cfg> RegistryData for HttpRegistry<'cfg> {
 
         // Enable HTTP/2 if possible.
         if self.multiplexing {
-            handle.http_version(HttpVersion::V2)?;
+            try_old_curl!(handle.http_version(HttpVersion::V2), "HTTP2");
         } else {
             handle.http_version(HttpVersion::V11)?;
         }