ios: retry curl with http1.1, attempt to fix curl failure

Author: clintonsteiner

Apple/__main__.py

@@ -345,16 +345,36 @@ def download(url: str, target_dir: Path) -> Path:
 
     out_path = target_path / basename(url)
     if not Path(out_path).is_file():
-        run([
-            "curl",
-            "-Lf",
-            "--retry",
-            "5",
-            "--retry-all-errors",
-            "-o",
-            out_path,
-            url,
-        ])
+        curl_attempts = [
+            [],
+            # Retry over HTTP/1.1 if the initial transfer fails with a curl
+            # transport error (commonly seen with some runner/proxy setups).
+            ["--http1.1"],
+        ]
+        for i, extra_args in enumerate(curl_attempts, 1):
+            try:
+                run([
+                    "curl",
+                    "-Lf",
+                    "--retry",
+                    "5",
+                    "--retry-all-errors",
+                    *extra_args,
+                    "-o",
+                    out_path,
+                    url,
+                ])
+            except CalledProcessError as exc:
+                if i < len(curl_attempts) and exc.returncode in {16, 56, 92}:
+                    out_path.unlink(missing_ok=True)
+                    print(
+                        f"curl exited {exc.returncode}; "
+                        "retrying download with --http1.1"
+                    )
+                    continue
+                raise
+            else:
+                break
     else:
         print(f"Using cached version of {basename(url)}")
     return out_path