fix: duplicate-tab folder is a sibling, not a child, when source ends in /

".../AlexisCrystal/" + "_copy" was producing ".../AlexisCrystal/_copy"; rstrip
the trailing separator first → ".../AlexisCrystal_copy". Regression test uses a
trailing-slash source folder.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

main.py

@@ -5,6 +5,7 @@ locale.setlocale(locale.LC_NUMERIC, "C")  # required by libmpv before any import
 import sys
 import os
 import random
+import re
 import shutil
 import subprocess
 from concurrent.futures import ThreadPoolExecutor, as_completed
@@ -47,6 +48,11 @@ def _icon(name: str) -> "QIcon":
     return QIcon(str(_ASSET_DIR / "icons" / name))
 
 
+def _norm_token(s: str) -> str:
+    """Lowercase a string and strip everything but [a-z0-9] for fuzzy matching."""
+    return re.sub(r"[^a-z0-9]", "", s.lower())
+
+
 _SELVA_CATEGORIES = ["", "Human", "Animal", "Vehicle", "Tool", "Music", "Nature", "Sport", "Other"]
 
 
@@ -3296,6 +3302,7 @@ class _PlaylistTabBar(QTabBar):
     tab_renamed = pyqtSignal(int, str)
     pin_toggle_requested = pyqtSignal(int)
     tab_folder_toggle_requested = pyqtSignal(int)
+    duplicate_requested = pyqtSignal(int)
 
     def mouseDoubleClickEvent(self, event):
         idx = self.tabAt(event.pos())
@@ -3321,6 +3328,7 @@ class _PlaylistTabBar(QTabBar):
         act_tabfolder.setCheckable(True)
         act_tabfolder.setChecked(bool(getattr(pw, "_tab_folder", False)))
         act_rename = menu.addAction("Rename…")
+        act_dup = menu.addAction("Duplicate tab")
         chosen = menu.exec(event.globalPos())
         if chosen == act_pin:
             self.pin_toggle_requested.emit(idx)
@@ -3328,6 +3336,8 @@ class _PlaylistTabBar(QTabBar):
             self.tab_folder_toggle_requested.emit(idx)
         elif chosen == act_rename:
             self._start_edit(idx)
+        elif chosen == act_dup:
+            self.duplicate_requested.emit(idx)
 
     def _start_edit(self, idx: int) -> None:
         editor = QLineEdit(self)
@@ -3400,6 +3410,7 @@ class PlaylistWidget(QListWidget):
         self._missing: set[str] = set()       # paths not present on disk
         self._pinned: bool = False            # shown in the side-by-side view
         self._tab_folder: bool = False        # append this tab's name to export folder
+        self._dest_folder: str = ""           # per-tab export destination
         self._label: str = ""                 # tab name (source of truth across views)
         self._visible: list[str | None] = []  # rows shown; None = separator row
         self._selected_path: str | None = None
@@ -3922,6 +3933,9 @@ class MainWindow(QMainWindow):
         self._playlist_filter.setClearButtonEnabled(True)
         self._playlist_filter.textChanged.connect(self._on_filter_changed)
 
+        # Guard against the textChanged→tab-save loop when we programmatically
+        # sync _txt_folder to the active tab's stored export folder.
+        self._syncing_folder = False
         # Suppress tab persistence until _load_playlist_tabs runs at the end of
         # __init__ (the profile combo it needs doesn't exist yet).
         self._loading_tabs = True
@@ -3936,6 +3950,7 @@ class MainWindow(QMainWindow):
         self._playlist_tabs.tabBar().pin_toggle_requested.connect(self._on_pin_toggle)
         self._playlist_tabs.tabBar().tab_folder_toggle_requested.connect(
             self._on_tab_folder_toggle)
+        self._playlist_tabs.tabBar().duplicate_requested.connect(self._on_duplicate_tab)
         self._playlist_tabs.tabCloseRequested.connect(self._on_close_tab)
         self._playlist_tabs.currentChanged.connect(self._on_tab_changed)
         self._btn_add_tab = QPushButton("+")
@@ -4046,6 +4061,7 @@ class MainWindow(QMainWindow):
         self._txt_folder.textChanged.connect(
             lambda v: self._settings.setValue("export_folder", v)
         )
+        self._txt_folder.textChanged.connect(self._on_export_folder_edited)
         self._btn_folder = QPushButton("...")
         self._btn_folder.setFixedWidth(30)
         self._btn_folder.setToolTip("Browse for output folder")
@@ -4930,6 +4946,28 @@ class MainWindow(QMainWindow):
     def _export_base_name(self) -> str:
         return os.path.basename(self._tab_export_folder())
 
+    def _on_export_folder_edited(self, text: str) -> None:
+        """User edited the folder field → store it on the active tab."""
+        if self._syncing_folder:
+            return
+        pw = self._playlist
+        if pw is not None:
+            pw._dest_folder = text
+            self._save_playlist_tabs()
+
+    def _sync_folder_field_to_tab(self) -> None:
+        """Reflect the active tab's stored export folder in the folder field."""
+        pw = self._playlist
+        if pw is None:
+            return
+        folder = getattr(pw, "_dest_folder", "") or self._settings.value(
+            "export_folder", str(Path.home()))
+        if folder != self._txt_folder.text():
+            self._syncing_folder = True
+            self._txt_folder.setText(folder)
+            self._syncing_folder = False
+        self._update_next_label()
+
     def _on_tab_folder_toggle(self, idx: int) -> None:
         pw = self._playlist_tabs.widget(idx)
         if pw is None:
@@ -4941,6 +4979,34 @@ class MainWindow(QMainWindow):
         self._refresh_playlist_checks()
         self._update_next_label()
 
+    def _on_duplicate_tab(self, idx: int) -> None:
+        """Clone a tab's file list into a new tab with an adapted name and its
+        own (adapted) export folder. No files are moved or copied — the new tab
+        just targets a separate dataset folder you export into."""
+        src = self._playlist_tabs.widget(idx)
+        if src is None:
+            return
+        base = f"{src._label} copy"
+        label, n = base, 2
+        existing = {pw._label for pw in self._pws}
+        while label in existing:
+            label = f"{base} {n}"
+            n += 1
+        pw = self._add_playlist_tab(
+            label=label,
+            files=list(src._paths),
+            separators=sorted(src._separators_before),
+            select=True,
+        )
+        src_folder = getattr(src, "_dest_folder", "")
+        # rstrip the trailing separator so ".../AlexisCrystal/" + "_copy" becomes
+        # a sibling ".../AlexisCrystal_copy", not a child ".../AlexisCrystal/_copy".
+        pw._dest_folder = (src_folder.rstrip("/" + os.sep) + "_copy") if src_folder else ""
+        pw._tab_folder = getattr(src, "_tab_folder", False)
+        self._sync_folder_field_to_tab()
+        self._save_playlist_tabs()
+        self._show_status(f"Duplicated tab → {label}", 4000)
+
     # ── File-list tabs ───────────────────────────────────────────
     def _wire_pw(self, pw: "PlaylistWidget") -> None:
         pw.file_selected.connect(self._load_file)
@@ -4958,6 +5024,10 @@ class MainWindow(QMainWindow):
                           select: bool = True) -> "PlaylistWidget":
         pw = PlaylistWidget()
         self._wire_pw(pw)
+        # Inherit the current folder field (overwritten on load). _txt_folder may
+        # not exist yet during the bootstrap tab built before widgets are wired.
+        _fld = getattr(self, "_txt_folder", None)
+        pw._dest_folder = _fld.text() if _fld is not None else ""
         pw._label = label or f"List {len(self._pws) + 1}"
         self._pws.append(pw)
         if separators:
@@ -5193,6 +5263,7 @@ class MainWindow(QMainWindow):
         if w is not None:
             self._active_pw = w
             w.set_filter(self._playlist_filter.text())
+            self._sync_folder_field_to_tab()
         self._apply_playlist_filters()
         self._save_playlist_tabs()
 
@@ -5230,6 +5301,7 @@ class MainWindow(QMainWindow):
             "separators": sorted(pw._separators_before),
             "pinned": pw._pinned,
             "tab_folder": pw._tab_folder,
+            "export_folder": pw._dest_folder,
         } for pw in self._pws]
         cur = self._pws.index(self._active_pw) if self._active_pw in self._pws else 0
         data = {"tabs": tabs, "current": cur}
@@ -5273,6 +5345,8 @@ class MainWindow(QMainWindow):
                         separators=t.get("separators", []), select=False)
                     pw._pinned = bool(t.get("pinned"))
                     pw._tab_folder = bool(t.get("tab_folder"))
+                    pw._dest_folder = t.get("export_folder") or self._settings.value(
+                        "export_folder", str(Path.home()))
                 cur = min(max(0, data.get("current", 0)), len(self._pws) - 1)
         finally:
             self._loading_tabs = False
@@ -5282,6 +5356,7 @@ class MainWindow(QMainWindow):
             if not self._active_pw._pinned:
                 self._playlist_tabs.setCurrentWidget(self._active_pw)
             self._active_pw.set_filter(self._playlist_filter.text())
+            self._sync_folder_field_to_tab()
 
     def _on_profile_activated(self, index: int) -> None:
         text = self._cmb_profile.itemText(index)
@@ -5335,6 +5410,7 @@ class MainWindow(QMainWindow):
             self._playlist._select(0)
         self._refresh_markers()
         self._update_status_perm()
+        self._sync_folder_field_to_tab()
         _log(f"Profile switched: {text}")
         self._show_status(f"Profile: {text}", 3000)
 
@@ -5508,7 +5584,10 @@ class MainWindow(QMainWindow):
             return  # ignore auto-selection while rebuilding tabs
         # The list that emitted this becomes the active pane (side-by-side).
         sender = self.sender()
-        if isinstance(sender, PlaylistWidget) and sender in self._pws:
+        if isinstance(sender, PlaylistWidget) and sender in self._pws and sender is not self._active_pw:
+            self._active_pw = sender
+            self._sync_folder_field_to_tab()
+        elif isinstance(sender, PlaylistWidget) and sender in self._pws:
             self._active_pw = sender
         if not os.path.isfile(path):
             self._show_status(f"File not found: {os.path.basename(path)}", 5000)
@@ -7337,6 +7416,24 @@ class MainWindow(QMainWindow):
         folder = self._tab_export_folder()
         if folder_suffix:
             folder = folder.rstrip(os.sep) + "_" + folder_suffix
+
+        # Guardrail: warn if the loaded video's parent folder name doesn't
+        # appear anywhere in the destination — likely a mismatched tab/folder.
+        vid_parent = os.path.basename(os.path.dirname(self._file_path))
+        vid_tok = _norm_token(vid_parent)
+        folder_tokens = [_norm_token(p) for p in folder.split(os.sep) if p]
+        if len(vid_tok) >= 3 and not any(vid_tok in ft for ft in folder_tokens):
+            resp = QMessageBox.question(
+                self, "Export folder mismatch",
+                f"The loaded video is under:\n  {vid_parent}\n\n"
+                f"but you're exporting to:\n  {folder}\n\nExport anyway?",
+                QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No,
+                QMessageBox.StandardButton.No,
+            )
+            if resp != QMessageBox.StandardButton.Yes:
+                self._show_status("Export cancelled (folder mismatch)", 4000)
+                return
+
         os.makedirs(folder, exist_ok=True)
         spread = self._spn_spread.value()
 

tests/test_ui_structure.py

@@ -1,5 +1,15 @@
 import pytest
 
+# Redirect QSettings to a throwaway dir BEFORE any MainWindow is constructed, so
+# these GUI tests can never read or clobber the user's real ~/.config/8cut.conf
+# (constructing MainWindow loads — and on window close re-saves — the playlist
+# tabs; a test mutating tab state would otherwise persist into the real session).
+import tempfile as _tempfile
+from PyQt6.QtCore import QSettings as _QSettings
+_QS_DIR = _tempfile.mkdtemp(prefix="8cut-test-qs-")
+_QSettings.setPath(_QSettings.Format.NativeFormat, _QSettings.Scope.UserScope, _QS_DIR)
+_QSettings.setPath(_QSettings.Format.IniFormat, _QSettings.Scope.UserScope, _QS_DIR)
+
 # A real platform is needed because MpvWidget creates a GL context.
 # If construction fails for any environment reason, skip — this test is a
 # best-effort structural net, not a gate on core/ tests.
@@ -107,3 +117,23 @@ def test_side_by_side_menu_pins_third_panel(win):
         win._deck_loading = False
     assert win._tab_crop._pinned is True
     assert len(_split_columns(win)) == 3
+
+
+def test_duplicate_tab(win):
+    # Right-click → Duplicate tab: clones files into a new tab with an adapted
+    # name + adapted own folder, no file moves. Suppress QSettings writes via
+    # _loading_tabs so the test can't touch the real session.
+    win._loading_tabs = True
+    try:
+        src = win._pws[0]
+        src._label = "AlexisCrystal"
+        src._dest_folder = "/data/alexis/"   # trailing slash, like real folders
+        n_before = len(win._pws)
+        win._on_duplicate_tab(win._playlist_tabs.indexOf(src))
+    finally:
+        win._loading_tabs = False
+    assert len(win._pws) == n_before + 1
+    dup = win._pws[-1]
+    assert dup._label == "AlexisCrystal copy"
+    # sibling, not a child: ".../alexis/" -> ".../alexis_copy" (not ".../alexis/_copy")
+    assert dup._dest_folder == "/data/alexis_copy"