fix: name the cfg behind a closed detected folder

install.py

@@ -8905,8 +8905,9 @@ def _open_from_folders(folders: list[Path]) -> None:
                     other_drives=[str(drive) for drive in index.other_drives])
 
 
-def _refuse_closed(dest: Path, named: str) -> None:
-    """End the run, with its name, on a folder above dest this user cannot open."""
+def _refuse_closed(dest: Path, named: str, then: str = "") -> None:
+    """End the run, with its name, on a folder above dest this user cannot
+    open. then is a line said after the error, which it continues."""
     closed = closed_folder(dest)
     if closed is None:
         return
@@ -8915,6 +8916,8 @@ def _refuse_closed(dest: Path, named: str) -> None:
     print(f"Error: {screen_text(message)}. Give this user access to it, run as "
           f"its owner, or choose another folder than the one {named}.",
           file=sys.stderr)
+    if then:
+        print(f"  {then}", file=sys.stderr)
     sys.exit(1)
 
 
@@ -9366,13 +9369,13 @@ def _install(args: argparse.Namespace, real_stdout: TextIO) -> None:
         # A system_directory under /root read from retroarch.cfg, run without
         # sudo: the case probe raised PermissionError before any line.
         for name, path in platforms:
-            if closed_folder(path) is not None and len(platforms) > 1:
-                print("  Nothing was installed. Name one platform with --platform "
-                      "to install it alone.", file=sys.stderr)
-            _refuse_closed(path, (
-                f"taken as {display_name(name)}'s default, {display_name(name)} "
-                "not being found here" if path in assumed_dests
-                else "detected here") + " (name another with --dest)")
+            found_in = _retroarch_config_at(path)
+            named = (f"used by default, since {display_name(name)} was not found"
+                     if path in assumed_dests
+                     else f"{found_in[0]} names" if found_in else "detected here")
+            _refuse_closed(path, f"{named} (name another with --dest)",
+                           "Nothing was installed. Name one platform with --platform "
+                           "to install it alone." if len(platforms) > 1 else "")
 
     total_downloaded = 0
     total_up_to_date = 0

tests/test_install_experience.py

@@ -1119,5 +1119,58 @@ class NotFoundWithAClosedFolder(unittest.TestCase):
         self.assertIn("could not be opened", asked[0])
 
 
+@unittest.skipIf(os.name == "nt" or os.geteuid() == 0,
+                 "a folder without search permission is POSIX")
+class ADetectedClosedFolderSaysWhereItCameFrom(unittest.TestCase):
+    """The refusal said "the one detected here" for a folder retroarch.cfg
+    names, and with two setups found the line saying nothing was installed
+    came above the error it continues."""
+
+    def run_detected(self, emudeck: bool) -> subprocess.CompletedProcess:
+        with FakeRepository() as repo:
+            home = repo.root / "home"
+            lock = repo.root / "lock"
+            cfg = home / ".config" / "retroarch" / "retroarch.cfg"
+            cfg.parent.mkdir(parents=True)
+            (lock / "system").mkdir(parents=True)
+            cfg.write_text(f'system_directory = "{lock / "system"}"\n')
+            if emudeck:
+                (home / "Emulation" / "bios").mkdir(parents=True)
+            env = {**repo.env(), "HOME": str(home), "XDG_CONFIG_HOME": str(home / ".config"),
+                   "RETROBIOS_OS": "linux"}
+            os.chmod(lock, 0o000)
+            try:
+                proc = subprocess.run(
+                    [sys.executable, str(REPO_ROOT / "install.py"), "--check", "--no-input"],
+                    env=env, capture_output=True, text=True, timeout=60,
+                    stdin=subprocess.DEVNULL)
+            finally:
+                os.chmod(lock, 0o755)
+        self.cfg = cfg
+        return proc
+
+    def test_the_config_is_named(self):
+        proc = self.run_detected(False)
+        self.assertEqual(proc.returncode, 1, proc.stdout + proc.stderr)
+        said = " ".join(proc.stderr.split())
+        self.assertIn(f"than the one {self.cfg} names (name another with --dest)", said)
+
+    def test_nothing_installed_comes_after_the_error(self):
+        proc = self.run_detected(True)
+        self.assertEqual(proc.returncode, 1, proc.stdout + proc.stderr)
+        error = proc.stderr.index("Error: ")
+        self.assertGreater(proc.stderr.index("Nothing was installed."), error, proc.stderr)
+
+    def test_an_assumed_default_reads_plainly(self):
+        self.assertIn("used by default, since {display_name(name)} was not found",
+                      _source_of(install._run_text))
+
+
+def _source_of(function) -> str:
+    import inspect
+
+    return " ".join(inspect.getsource(function).split())
+
+
 if __name__ == "__main__":
     unittest.main()