testsuite: run the generic timestamp tests on win32, see #8730

is_utime_fully_supported() and is_birthtime_fully_supported() probed via
os.utime, which can neither set the timestamps of a symlink itself nor the
birthtime on win32 - so they returned False there and all the tests they
guard were skipped. Probe via platform.set_times() instead, which does the
right thing on all platforms.

Also: a FILETIME has a resolution of 100ns, use that for st_mtime_ns_round
on win32 (rather than the 1s fallback).

Co-Authored-By: Claude Opus 5 <[email protected]>

src/borg/testsuite/__init__.py

@@ -22,6 +22,9 @@ except:  # noqa
 
 from ..fuse_impl import llfuse, has_any_fuse, has_llfuse, has_pyfuse3, has_mfusepy, ENOATTR  # NOQA
 from .. import platform
+
+# import these directly: the borg.testsuite.platform subpackage shadows the platform name above.
+from ..platform import get_birthtime_ns, set_times
 from ..platformflags import is_win32, is_darwin
 
 # Does this version of llfuse support ns precision?
@@ -47,6 +50,9 @@ else:
 if sys.platform.startswith("netbsd"):
     st_mtime_ns_round = -4  # 10us - strange: only >1 microsecond resolution here?
 
+if is_win32:
+    st_mtime_ns_round = -2  # 100ns - the resolution of a FILETIME, see platform.windows.set_times
+
 
 def same_ts_ns(ts_ns1, ts_ns2):
     """Compare two timestamps (both in nanoseconds) to determine whether they are (roughly) equal."""
@@ -207,16 +213,19 @@ def are_fifos_supported():
 
 @functools.lru_cache
 def is_utime_fully_supported():
+    # note: platform.set_times is used rather than os.utime, because os.utime can not set the
+    # timestamps of a symlink itself on win32 (it raises NotImplementedError there), see #8730.
     with unopened_tempfile() as filepath:
-        # Some filesystems (such as SSHFS) don't support utime on symlinks
+        # Some filesystems (such as SSHFS) don't support setting the timestamps of symlinks
         if are_symlinks_supported():
             os.symlink("something", filepath)
         else:
             open(filepath, "w").close()
         try:
-            os.utime(filepath, (1000, 2000), follow_symlinks=False)
+            atime_ns, mtime_ns = 1000 * 10**9, 2000 * 10**9
+            set_times(filepath, atime_ns=atime_ns, mtime_ns=mtime_ns, follow_symlinks=False)
             new_stats = os.stat(filepath, follow_symlinks=False)
-            if new_stats.st_atime == 1000 and new_stats.st_mtime == 2000:
+            if new_stats.st_atime_ns == atime_ns and new_stats.st_mtime_ns == mtime_ns:
                 return True
         except OSError:
             pass
@@ -227,20 +236,23 @@ def is_utime_fully_supported():
 
 @functools.lru_cache
 def is_birthtime_fully_supported():
-    if not hasattr(os.stat_result, "st_birthtime"):
-        return False
+    # note: platform.set_times is used rather than the "os.utime twice" trick, because that only
+    # works on the BSDs and on macOS - on win32, the birthtime needs SetFileTime, see #8730.
     with unopened_tempfile() as filepath:
-        # Some filesystems (such as SSHFS) don't support utime on symlinks
+        # Some filesystems (such as SSHFS) don't support setting the timestamps of symlinks
         if are_symlinks_supported():
             os.symlink("something", filepath)
         else:
             open(filepath, "w").close()
         try:
-            birthtime, mtime, atime = 946598400, 946684800, 946771200
-            os.utime(filepath, (atime, birthtime), follow_symlinks=False)
-            os.utime(filepath, (atime, mtime), follow_symlinks=False)
+            birthtime_ns, mtime_ns, atime_ns = 946598400 * 10**9, 946684800 * 10**9, 946771200 * 10**9
+            set_times(filepath, atime_ns=atime_ns, mtime_ns=mtime_ns, birthtime_ns=birthtime_ns, follow_symlinks=False)
             new_stats = os.stat(filepath, follow_symlinks=False)
-            if new_stats.st_birthtime == birthtime and new_stats.st_mtime == mtime and new_stats.st_atime == atime:
+            if (
+                get_birthtime_ns(new_stats, filepath) == birthtime_ns
+                and new_stats.st_mtime_ns == mtime_ns
+                and new_stats.st_atime_ns == atime_ns
+            ):
                 return True
         except OSError:
             pass

src/borg/testsuite/archiver/create_cmd_test.py

@@ -252,19 +252,24 @@ def test_unix_socket(archivers, request, monkeypatch):
 def test_nobirthtime(archivers, request):
     archiver = request.getfixturevalue(archivers)
     create_test_files(archiver.input_path)
-    birthtime, mtime, atime = 946598400, 946684800, 946771200
-    os.utime("input/file1", (atime, birthtime))
-    os.utime("input/file1", (atime, mtime))
+    birthtime_ns, mtime_ns, atime_ns = 946598400 * 10**9, 946684800 * 10**9, 946771200 * 10**9
+    platform.set_times("input/file1", atime_ns=atime_ns, mtime_ns=mtime_ns, birthtime_ns=birthtime_ns)
     cmd(archiver, "repo-create", RK_ENCRYPTION)
     cmd(archiver, "create", "test", "input", "--nobirthtime")
     with changedir("output"):
         cmd(archiver, "extract", "test")
     sti = os.stat("input/file1")
     sto = os.stat("output/input/file1")
-    assert same_ts_ns(sti.st_birthtime * 1e9, birthtime * 1e9)
-    assert same_ts_ns(sto.st_birthtime * 1e9, mtime * 1e9)
+    assert same_ts_ns(platform.get_birthtime_ns(sti, "input/file1"), birthtime_ns)
+    birthtime_out = platform.get_birthtime_ns(sto, "output/input/file1")
+    if is_win32:
+        # win32 keeps the creation time the extracted file got when it was created.
+        assert not same_ts_ns(birthtime_out, birthtime_ns)
+    else:
+        # posix: setting an mtime older than the birthtime pulls the birthtime back to it.
+        assert same_ts_ns(birthtime_out, mtime_ns)
     assert same_ts_ns(sti.st_mtime_ns, sto.st_mtime_ns)
-    assert same_ts_ns(sto.st_mtime_ns, mtime * 10**9)
+    assert same_ts_ns(sto.st_mtime_ns, mtime_ns)
 
 
 def test_create_stdin(archivers, request):

src/borg/testsuite/archiver/extract_cmd_test.py

@@ -310,6 +310,7 @@ def test_atime(archivers, request):
         assert same_ts_ns(sto.st_atime_ns, atime * 10**9)
 
 
+@pytest.mark.skipif(is_win32, reason="no os.pread and no O_NOATIME on win32")
 @pytest.mark.skipif(not is_utime_fully_supported(), reason="cannot properly setup and execute test without utime")
 def test_atime_open_updates_atime(archiver):
     # simulate a platform where already the open() updates the atime (no O_NOATIME support,
@@ -356,19 +357,20 @@ def test_atime_open_updates_atime(archiver):
 def test_birthtime(archivers, request):
     archiver = request.getfixturevalue(archivers)
     create_test_files(archiver.input_path)
-    birthtime, mtime, atime = 946598400, 946684800, 946771200
-    os.utime("input/file1", (atime, birthtime))
-    os.utime("input/file1", (atime, mtime))
+    birthtime_ns, mtime_ns, atime_ns = 946598400 * 10**9, 946684800 * 10**9, 946771200 * 10**9
+    platform.set_times("input/file1", atime_ns=atime_ns, mtime_ns=mtime_ns, birthtime_ns=birthtime_ns)
     cmd(archiver, "repo-create", RK_ENCRYPTION)
     cmd(archiver, "create", "test", "input")
     with changedir("output"):
         cmd(archiver, "extract", "test")
     sti = os.stat("input/file1")
     sto = os.stat("output/input/file1")
-    assert same_ts_ns(sti.st_birthtime * 1e9, sto.st_birthtime * 1e9)
-    assert same_ts_ns(sto.st_birthtime * 1e9, birthtime * 1e9)
+    birthtime_in = get_birthtime_ns(sti, "input/file1")
+    birthtime_out = get_birthtime_ns(sto, "output/input/file1")
+    assert same_ts_ns(birthtime_in, birthtime_out)
+    assert same_ts_ns(birthtime_out, birthtime_ns)
     assert same_ts_ns(sti.st_mtime_ns, sto.st_mtime_ns)
-    assert same_ts_ns(sto.st_mtime_ns, mtime * 10**9)
+    assert same_ts_ns(sto.st_mtime_ns, mtime_ns)
 
 
 @pytest.mark.skipif(not is_win32, reason="Windows-only test")