fix: take a backup folder on one-owner storage

install.ps1

@@ -11,7 +11,7 @@
 
     $ErrorActionPreference = "Stop"
     $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-    $defaultInstallSha256 = "b3363820bb97bec559287f72d9712281e22307387fa752b663f6f7af023a0e33"
+    $defaultInstallSha256 = "cc940a96dea46fb43d3940a13fddb4c9f1c02b8d81d1c810bcbddd5120143ce4"
     $maximumInstallerBytes = 2MB
     $installerExit = 0
     $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }

install.py

@@ -4468,15 +4468,19 @@ def _check_holder(holder: Path) -> os.stat_result:
 
     A link would send them wherever it points. On a system with user ids, a
     folder another user owns was not made by this user's runs, and its owner
-    could read or swap what is moved in. Returns what was checked, so the
-    caller can confirm the same folder is still there once it has written
-    into it.
+    could read or swap what is moved in. A storage that keeps no owner per
+    file gives every file one owner: Android's shared storage shows a folder
+    Termux has just made as another user's, as does a FAT card. A holder
+    owned like the folder it sits in is that storage's owner, not someone
+    else's folder. Returns what was checked, so the caller can confirm the
+    same folder is still there once it has written into it.
     """
     info = os.lstat(holder)
     if not stat.S_ISDIR(info.st_mode):
         raise OSError(errno.ELOOP, f"{holder} is a link or not a folder")
     getuid = getattr(os, "getuid", None)
-    if getuid is not None and info.st_uid != getuid():
+    if (getuid is not None and info.st_uid != getuid()
+            and info.st_uid != os.lstat(holder.parent).st_uid):
         raise OSError(errno.EPERM, f"{holder} belongs to another user")
     return info
 
@@ -5497,6 +5501,12 @@ def _report_outcome(
                       "(or delete them), then run again.")
     if any(isinstance(reason, NetworkReason) for _dest, reason in failures or []):
         advice.append(NETWORK_FAILURE_ADVICE)
+    if any(str(reason).startswith(NOT_KEPT) for _dest, reason in failures or []):
+        # The same run fails the same way: "retry only those" sent a phone
+        # user round the loop with nothing changed.
+        advice.append("  The files in place were left as they were, as no backup folder could "
+                      "be made for them. Move them out of the folder, then run again to "
+                      "install the new ones.")
     paths = paths + [folder for folder in elsewhere if folder not in paths]
 
     if offline:
@@ -5554,7 +5564,8 @@ def _report_outcome(
         print(f"Location: {_locations(paths)}")
         for line in kept + advice:
             print(line)
-        print("Run the same command again to retry only those.")
+        if not all(str(reason).startswith(NOT_KEPT) for _dest, reason in failures or []):
+            print("Run the same command again to retry only those.")
         sys.exit(1)
 
     print(f"\nDone. {_plural(downloaded, 'file')} installed, "

install.sh

@@ -18,7 +18,7 @@ esac
 TEMP_INSTALLER=""
 TEMP_DIRECTORY=""
 DEFAULT_INSTALL_URL="https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-DEFAULT_INSTALL_SHA256="b3363820bb97bec559287f72d9712281e22307387fa752b663f6f7af023a0e33"
+DEFAULT_INSTALL_SHA256="cc940a96dea46fb43d3940a13fddb4c9f1c02b8d81d1c810bcbddd5120143ce4"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {

install/launchers/index.json

@@ -27,8 +27,8 @@
         {
           "dest": "roms/ports/retrobios/install.py",
           "repo_path": "install.py",
-          "size": 734772,
-          "sha256": "b3363820bb97bec559287f72d9712281e22307387fa752b663f6f7af023a0e33",
+          "size": 735645,
+          "sha256": "cc940a96dea46fb43d3940a13fddb4c9f1c02b8d81d1c810bcbddd5120143ce4",
           "executable": false
         },
         {
@@ -71,8 +71,8 @@
     "muos": {
       "archive": {
         "dest": "ARCHIVE/RetroBIOS.muxapp",
-        "size": 787321,
-        "sha256": "45366e0a225d8143f7b359fd04cd6b341a21f43057b7d5a41ad8f734f765f142"
+        "size": 788194,
+        "sha256": "3a9bc441d4178cc15833dc8a3f28877370b4075a05131d209208186247756cc7"
       },
       "members": [
         {
@@ -92,8 +92,8 @@
         {
           "name": "RetroBIOS/install.py",
           "repo_path": "install.py",
-          "size": 734772,
-          "sha256": "b3363820bb97bec559287f72d9712281e22307387fa752b663f6f7af023a0e33",
+          "size": 735645,
+          "sha256": "cc940a96dea46fb43d3940a13fddb4c9f1c02b8d81d1c810bcbddd5120143ce4",
           "executable": false
         },
         {
@@ -166,8 +166,8 @@
         {
           "dest": ".config/modules/retrobios/install.py",
           "repo_path": "install.py",
-          "size": 734772,
-          "sha256": "b3363820bb97bec559287f72d9712281e22307387fa752b663f6f7af023a0e33",
+          "size": 735645,
+          "sha256": "cc940a96dea46fb43d3940a13fddb4c9f1c02b8d81d1c810bcbddd5120143ce4",
           "executable": false
         },
         {

tests/test_install.py

@@ -9,6 +9,7 @@ import importlib.util
 import io
 import json
 import os
+import stat
 import shlex
 import re
 import shutil
@@ -5737,11 +5738,35 @@ class AFileYouHadIsKept(unittest.TestCase):
 
     @unittest.skipUnless(hasattr(os, "getuid"), "user ids are POSIX")
     def test_a_holder_another_user_owns_is_refused(self):
-        (self.home / install.BACKUP_DIR).mkdir()
-        with self.assertRaises(OSError):
-            with unittest.mock.patch.object(install.os, "getuid", return_value=os.getuid() + 1):
-                install._check_holder(self.home / install.BACKUP_DIR)
-        install._check_holder(self.home / install.BACKUP_DIR)
+        holder = self.home / install.BACKUP_DIR
+        holder.mkdir()
+        real = os.lstat
+
+        def planted(path, *args, **kwargs):
+            info = real(path, *args, **kwargs)
+            if Path(path) != holder:
+                return info
+            fields = list(info)
+            fields[stat.ST_UID] = info.st_uid + 2
+            return os.stat_result(fields)
+
+        with self.assertRaises(OSError), \
+                unittest.mock.patch.object(install.os, "lstat", side_effect=planted):
+            install._check_holder(holder)
+        install._check_holder(holder)
+
+    @unittest.skipUnless(hasattr(os, "getuid"), "user ids are POSIX")
+    def test_a_storage_with_one_owner_for_every_file_takes_the_holder(self):
+        # Android's shared storage, seen from Termux on Android 17: a folder
+        # the run has just made is shown as another user's, like every other
+        # file there. Refusing it left 25 files unreplaced on a real phone.
+        holder = self.home / install.BACKUP_DIR
+        holder.mkdir()
+        with unittest.mock.patch.object(install.os, "getuid", return_value=os.getuid() + 1):
+            install._check_holder(holder)
+            (self.bios / "x.bin").write_bytes(self.OLD)
+            self.assertTrue(self._download("x.bin")[1])
+        self.assertEqual((self._run_folder() / "system" / "x.bin").read_bytes(), self.OLD)
 
     def test_restore_refuses_a_folder_the_installer_did_not_write(self):
         planted = self.home / install.BACKUP_DIR / "20260101-000000"

tests/test_install_experience.py

@@ -337,6 +337,21 @@ class ProgressOutput(unittest.TestCase):
         self.assertIn("failed: x.bin (HTTP 404)", out)
         self.assertIn("2.0 KB downloaded in 0:02", out)
 
+    def test_files_not_set_aside_get_a_remedy_not_a_retry(self):
+        # A real Android run: 25 files whose backup folder was refused, told
+        # to run again, which refuses them the same way.
+        reason = f"{install.NOT_KEPT} (/sdcard/RetroArch/retrobios-backup belongs to another user)"
+        buf = io.StringIO()
+        with contextlib.redirect_stdout(buf), self.assertRaises(SystemExit) as end:
+            install._report_outcome(
+                [Path("/b")], 3, 0, 2, 0, False,
+                failures=[("a.zip", reason), ("b.zip", reason)],
+            )
+        out = buf.getvalue()
+        self.assertEqual(end.exception.code, 1)
+        self.assertIn("The files in place were left as they were", out)
+        self.assertNotIn("retry only those", out)
+
 
 class CommandLine(unittest.TestCase):
     def test_a_dry_run_writes_nothing(self):