fix: correct singular/plural in macOS platform-tag warning

docs/news.rst

@@ -1,6 +1,12 @@
 Release Notes
 =============
 
+**UNRELEASED**
+
+- Fixed the macOS platform-tag warning always using the plural "these files"
+  wording, even when only a single library required a higher deployment target
+  (`#697 <https://github.com/pypa/wheel/pull/697>`_)
+
 **0.48.0 (2026-08-12)**
 
 - Added a ``--local-version`` option to ``wheel pack`` to add, replace, or remove a

src/wheel/macosx_libfile.py

@@ -456,19 +456,19 @@ def calculate_macosx_platform_tag(archive_root: StrPath, platform_tag: str) -> s
     fin_base_version = "_".join([str(x) for x in base_version])
     if start_version < base_version:
         problematic_files = [k for k, v in versions_dict.items() if v > start_version]
-        problematic_files = "\n".join(problematic_files)
         if len(problematic_files) == 1:
             files_form = "this file"
         else:
             files_form = "these files"
+        problematic_files_text = "\n".join(problematic_files)
         error_message = (
             "[WARNING] This wheel needs a higher macOS version than {}  "
             "To silence this warning, set MACOSX_DEPLOYMENT_TARGET to at least "
             + fin_base_version
             + " or recreate "
             + files_form
             + " with lower "
-            "MACOSX_DEPLOYMENT_TARGET:  \n" + problematic_files
+            "MACOSX_DEPLOYMENT_TARGET:  \n" + problematic_files_text
         )
 
         if "MACOSX_DEPLOYMENT_TARGET" in os.environ:

tests/test_macosx_libfile.py

@@ -0,0 +1,38 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from wheel import macosx_libfile
+from wheel.macosx_libfile import calculate_macosx_platform_tag
+
+
+@pytest.mark.parametrize(
+    ("dylib_count", "expected_form"),
+    [
+        pytest.param(1, "this file", id="single"),
+        pytest.param(2, "these files", id="multiple"),
+    ],
+)
+def test_calculate_macosx_platform_tag_files_form(
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+    dylib_count: int,
+    expected_form: str,
+) -> None:
+    for index in range(dylib_count):
+        tmp_path.joinpath(f"lib{index}.dylib").touch()
+
+    monkeypatch.setattr(
+        macosx_libfile,
+        "extract_macosx_min_system_version",
+        lambda path: (11, 0, 0),
+    )
+
+    tag = calculate_macosx_platform_tag(str(tmp_path), "macosx-10.9-x86_64")
+
+    assert tag == "macosx_11_0_x86_64"
+    warning = capsys.readouterr().err
+    assert expected_form in warning