fix: open the interface whatever owner files hold

An owner file holding a number past a pid raised OverflowError before
the screen opened, and a full temp disk stopped the run on the owner
write. 0 and negative numbers are unknown owners, not process groups.

install.ps1

@@ -11,7 +11,7 @@
 
     $ErrorActionPreference = "Stop"
     $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-    $defaultInstallSha256 = "c2a66e6b26004e96ef5f59a7fb5a2ed65bcaa9afc7602bd3e0d71f50cc561056"
+    $defaultInstallSha256 = "b23c6da4ee131f898c25540bd53677ea4112964fd00b209e4fe85dfdba8427d1"
     $maximumInstallerBytes = 2MB
     $installerExit = 0
     $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }

install.py

@@ -12279,8 +12279,9 @@ def _owner_alive(folder: Path) -> bool | None:
         pid = int((folder / TUI_OWNER).read_text(encoding="utf-8").strip())
     except (OSError, ValueError):
         return None
-    if os.name == "nt":
-        # os.kill(pid, 0) ends a process on Windows instead of asking.
+    if os.name == "nt" or pid <= 0:
+        # os.kill(pid, 0) ends a process on Windows instead of asking, and
+        # 0 or a negative number names a process group, not the run.
         return None
     try:
         os.kill(pid, 0)
@@ -12288,7 +12289,8 @@ def _owner_alive(folder: Path) -> bool | None:
         return False
     except PermissionError:
         return True
-    except OSError:
+    except (OSError, OverflowError):
+        # A number past what a pid holds is no process this run can ask.
         return None
     return True
 
@@ -12375,9 +12377,20 @@ def run_tui(args: argparse.Namespace) -> int:
     state, effects = started
     if flags["term"]:
         state.exit_code = 128 + flags["term"]
-    work = Path(tempfile.mkdtemp(prefix=TUI_WORK_PREFIX))
-    (work / TUI_OWNER).write_text(str(os.getpid()), encoding="utf-8")
-    _prune_work_folders(work.parent, time.time())
+    try:
+        work = Path(tempfile.mkdtemp(prefix=TUI_WORK_PREFIX))
+    except OSError as exc:
+        _restore_handlers(handlers)
+        print(f"Error: no work folder could be made in {tempfile.gettempdir()}: {exc}. "
+              "Free some space there, or point TMPDIR (TEMP on Windows) at another folder.", file=sys.stderr)
+        return 1
+    try:
+        (work / TUI_OWNER).write_text(str(os.getpid()), encoding="utf-8")
+    except OSError as exc:
+        # A full temp disk: the folder has no owner, and a later run leaves
+        # it a week like any unknown one. The logs fail as they come.
+        print(f"The work folder {work} could not be marked as this run's: {exc}",
+              file=sys.stderr)
     script = str(Path(__file__).resolve())
     inbox: queue.Queue = queue.Queue()
     current: list[_EngineRun] = []
@@ -12445,6 +12458,11 @@ def run_tui(args: argparse.Namespace) -> int:
             if number is not None:
                 handlers[number] = signal.signal(number, handler)
         sys.stdout = sys.stderr = buffer
+        try:
+            _prune_work_folders(work.parent, time.time())
+        except OSError as exc:
+            # What earlier runs left stays until a later run: this one opens.
+            print(f"Earlier work folders could not be removed: {exc}", file=sys.stderr)
         if state.exit_code is None:
             # Stopped while it started: the screen never opens.
             terminal.enter()

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="c2a66e6b26004e96ef5f59a7fb5a2ed65bcaa9afc7602bd3e0d71f50cc561056"
+DEFAULT_INSTALL_SHA256="b23c6da4ee131f898c25540bd53677ea4112964fd00b209e4fe85dfdba8427d1"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {

tests/test_install_tui.py

@@ -10,6 +10,7 @@ installs it).
 from __future__ import annotations
 
 import argparse
+import errno
 import fcntl
 import functools
 import hashlib
@@ -1801,6 +1802,31 @@ class WorkFolders(unittest.TestCase):
         work, out = self.run_to(130)
         self.assertFalse(work.exists())
 
+    def test_a_full_temp_disk_or_a_failing_pruner_still_opens(self):
+        real_write = Path.write_text
+
+        def full(path, *args, **kwargs):
+            if path.name == install.TUI_OWNER:
+                raise OSError(errno.ENOSPC, "No space left on device")
+            return real_write(path, *args, **kwargs)
+
+        with mock.patch.object(Path, "write_text", full):
+            work, out = self.run_to(0)
+        self.assertFalse(work.exists())
+        with mock.patch.object(install, "_prune_work_folders",
+                               side_effect=OSError(errno.EACCES, "denied")):
+            work, out = self.run_to(0)
+        self.assertFalse(work.exists())
+        err = io.StringIO()
+        with mock.patch.object(install.tempfile, "mkdtemp",
+                               side_effect=OSError(errno.ENOSPC, "No space left")), \
+                mock.patch.object(install, "tui_start", return_value=(fresh_state(), [])), \
+                mock.patch.object(install, "_open_local_sources"), \
+                mock.patch.object(install, "detect_os", return_value="linux"), \
+                mock.patch.object(sys, "stderr", err):
+            self.assertEqual(install.run_tui(_args()), 1)
+        self.assertIn("no work folder could be made", err.getvalue())
+
     def test_a_stop_while_it_starts_ends_on_the_farewell(self):
         """Start+Select during the detection: the signal is the interface's,
         never the default action that ended Python without a word."""
@@ -2456,8 +2482,17 @@ class AuditRoundThree(unittest.TestCase):
         unknown_old = folder("unknown-old", None, False, 2 * week)
         other = root / "something-else"
         other.mkdir()
+        # A stray or hostile owner file is an unknown owner: a number past
+        # what a pid holds raised OverflowError, and 0 or -1 name a group.
+        hostile = [folder(f"hostile{index}", None, False, 60)
+                   for index in range(3)]
+        for path, text in zip(hostile, ("9" * 40, "0", "-1")):
+            (path / install.TUI_OWNER).write_text(text)
+            self.assertIsNone(install._owner_alive(path))
         removed = install._prune_work_folders(root, now)
         self.assertEqual(sorted(removed), sorted([killed, failed_old, unknown_old]))
+        for path in hostile:
+            shutil.rmtree(path)
         self.assertEqual(sorted(path.name for path in root.iterdir()),
                          sorted(path.name for path in (running, failed, unknown, other)))