Merge branch 'main' into gh-72

src/manage/list_command.py

@@ -317,13 +317,34 @@ def execute(cmd):
     if cmd.source:
         from .indexutils import Index
         from .urlutils import IndexDownloader
-        try:
-            installs = _get_installs_from_index(
-                IndexDownloader(cmd.source, Index, disk_cache=cmd.download_dir),
-                tags,
-            )
-        except OSError as ex:
-            raise SystemExit(1) from ex
+        installs = []
+        first_exc = None
+        for source in [
+            None if cmd.fallback_source_only else cmd.source,
+            cmd.fallback_source,
+        ]:
+            if source:
+                try:
+                    installs = _get_installs_from_index(
+                        IndexDownloader(source, Index, disk_cache=cmd.download_dir),
+                        tags,
+                    )
+                    break
+                except OSError as ex:
+                    if first_exc is None:
+                        first_exc = ex
+        if first_exc:
+            raise SystemExit(1) from first_exc
+        if cmd.one:
+            # Pick the first non-prerelease that'll install for our platform
+            best = [i for i in installs
+                    if any(t.endswith(plat) for t in i.get("install-for", []))]
+            for i in best:
+                if not i["sort-version"].is_prerelease:
+                    installs = [i]
+                    break
+            else:
+                installs = best[:1] or installs
     elif cmd.install_dir:
         try:
             installs = cmd.get_installs(include_unmanaged=cmd.unmanaged)