Treat a project as spent once its song has been exported

Opening an exported song starts a fresh session from detection instead
of resuming: cuts, discards and metadata do not carry over, so a re-cut
never inherits decisions that have already shipped. --resume overrides
it on edit, export and project.

This reverses what was agreed in planning and written into docs/spec.md
and CONTEXT.md, which promised resume-across-sessions and re-export.
Both are corrected. The cost is deliberate and worth stating: changing
the width cap or adding the SVG renderer later now means re-cutting each
song by hand rather than regenerating every bundle from its project
file.

Export records the flag in bundle.write, so no caller can forget it.

Also removed --refit and the Auto-fit buttons, which were added without
being asked for and whose only purpose - migrating projects made before
the content rectangle was proposed - disappears once exported projects
start fresh. Reset now restores detection's proposal rather than the
whole page: clearing to full width would undo the thing the rectangle
exists for, so one button covers it.

open_project() replaces four copies of load-or-detect across the CLI
and the editor.

CONTEXT.md

@@ -51,9 +51,12 @@ two repos.
 **Project**:
 The persistent state of slicing one song: the source PDF it points at, its cuts,
 discards, content rectangle, levels, staff-height overrides, markers and
-metadata. Autosaved beside the PDF; the bundle is generated from it, so any
-export can be regenerated without repeating human work. One PDF, one song, one
-project, one bundle — never a many-to-one in any direction.
+metadata. Autosaved beside the PDF; the bundle is generated from it. One PDF,
+one song, one project, one bundle — never a many-to-one in any direction.
+
+**Spent** once its song has been exported: opening the PDF again begins a fresh
+session from detection rather than resuming, so a re-cut never inherits
+decisions that have already shipped.
 _Avoid_: session, document, edit list
 
 **Bundle**:

docs/spec.md

@@ -263,9 +263,19 @@ discards, content rectangle, skew angles, levels, staff-height overrides, marker
 and metadata. The bundle is *generated* from it, so export is a pure function of
 the project file plus the PDF.
 
-It buys crash safety, resume across sessions (authoring is trickle-in), and
-**re-export** — change the 1920 cap, fix one cut, or add the SVG renderer later,
-and every song's bundle regenerates without repeating any human work.
+It buys crash safety and resume across sessions, since authoring is trickle-in:
+a session interrupted halfway through a 12-page scan picks up exactly where it
+stopped.
+
+**A project is spent once its song has been exported.** Export records that in
+the file, and opening the PDF again starts a *fresh session from detection*
+rather than resuming. A re-cut therefore never inherits decisions that have
+already shipped. `--resume` overrides it on the `edit`, `export` and `project`
+commands when the old state really is wanted.
+
+The cost is deliberate: re-export is no longer free. Changing the width cap or
+adding the SVG renderer later means re-cutting each song by hand rather than
+regenerating every bundle from its project file.
 
 The project file references the PDF and never contains it; the hash lets the
 editor warn if the PDF changed underneath.

noteman_slicer/bundle.py

@@ -62,4 +62,10 @@ def write(project: Project, source: Source, path: Path) -> Path:
             zf.write(project.source, "original.pdf")
         for name, data in zip(names, images):
             zf.writestr(name, data, zipfile.ZIP_STORED)
+
+    # The project is spent once its song has been exported: the next edit
+    # session starts fresh from detection rather than resuming these decisions.
+    # Recorded here so no caller can forget it.
+    project.exported = True
+    project.save()
     return path

noteman_slicer/cli.py

@@ -51,32 +51,18 @@ def _detect(args: argparse.Namespace) -> int:
 
 
 def _project(args: argparse.Namespace) -> int:
-    from .project import Project, default_path
+    from .project import default_path, open_project
 
     source = open_source(args.pdf, SourceType(args.type) if args.type else None)
     path = default_path(source.path)
 
-    if path.exists() and not args.force:
-        project = Project.load(path)
-        print(f"{path.name}: loaded")
+    project = open_project(source, resume=args.resume and not args.force)
+    if project.path is None:
+        print(f"{path.name}: fresh session from detection")
+    else:
+        print(f"{path.name}: resumed")
         if project.source_changed():
             print("  WARNING: the PDF has changed since these cuts were made")
-        if args.refit:
-            # Re-propose the content rectangle without disturbing cuts,
-            # discards or metadata — for projects made before detection
-            # proposed one, or whose rectangle was dragged wrong.
-            for i in range(len(project.pages)):
-                gray = page_raster(source, i)
-                project.pages[i].content_rect = detect_page(gray).content
-            print(f"  content rectangle re-fitted on {len(project.pages)} pages")
-    else:
-        detections, heights = [], []
-        for i in range(len(source)):
-            gray = page_raster(source, i)
-            detections.append(detect_page(gray))
-            heights.append(gray.shape[0])
-        project = Project.from_detection(source.path, detections, heights)
-        print(f"{path.name}: created from detection")
 
     kept = project.kept_slices()
     for i, page in enumerate(project.pages):
@@ -92,23 +78,14 @@ def _project(args: argparse.Namespace) -> int:
 
 def _export(args: argparse.Namespace) -> int:
     from . import bundle
-    from .project import Project, default_path
+    from .project import open_project
 
     source = open_source(args.pdf, SourceType(args.type) if args.type else None)
-    path = default_path(source.path)
-
-    if path.exists():
-        project = Project.load(path)
-        if project.source_changed():
-            print("WARNING: the PDF has changed since these cuts were made")
-    else:
-        detections, heights = [], []
-        for i in range(len(source)):
-            gray = page_raster(source, i)
-            detections.append(detect_page(gray))
-            heights.append(gray.shape[0])
-        project = Project.from_detection(source.path, detections, heights)
-        print("no project file; exporting straight from detection")
+    project = open_project(source, resume=args.resume)
+    if project.path is None:
+        print("no unspent project state; exporting straight from detection")
+    elif project.source_changed():
+        print("WARNING: the PDF has changed since these cuts were made")
 
     out = Path(args.out) if args.out else source.path.with_suffix(".zip")
     bundle.write(project, source, out)
@@ -122,7 +99,9 @@ def _export(args: argparse.Namespace) -> int:
 def _edit(args: argparse.Namespace) -> int:
     from .editor import launch
 
-    return launch(Path(args.pdf), SourceType(args.type) if args.type else None)
+    return launch(
+        Path(args.pdf), SourceType(args.type) if args.type else None, resume=args.resume
+    )
 
 
 def main(argv: list[str] | None = None) -> int:
@@ -154,9 +133,9 @@ def main(argv: list[str] | None = None) -> int:
     proj.add_argument("--save", action="store_true", help="write the project file")
     proj.add_argument("--force", action="store_true", help="re-detect, discarding existing state")
     proj.add_argument(
-        "--refit",
+        "--resume",
         action="store_true",
-        help="re-propose the content rectangle, keeping cuts and metadata",
+        help="reopen an already-exported project instead of starting fresh",
     )
     proj.add_argument("--type", choices=[t.value for t in SourceType])
     proj.set_defaults(func=_project)
@@ -164,11 +143,17 @@ def main(argv: list[str] | None = None) -> int:
     exp = sub.add_parser("export", help="render the song and write a bundle")
     exp.add_argument("pdf")
     exp.add_argument("--out", help="output zip (default: alongside the PDF)")
+    exp.add_argument("--resume", action="store_true", help="use already-exported project state")
     exp.add_argument("--type", choices=[t.value for t in SourceType])
     exp.set_defaults(func=_export)
 
     ed = sub.add_parser("edit", help="open the editor")
     ed.add_argument("pdf")
+    ed.add_argument(
+        "--resume",
+        action="store_true",
+        help="reopen an already-exported project instead of starting fresh",
+    )
     ed.add_argument("--type", choices=[t.value for t in SourceType])
     ed.set_defaults(func=_edit)
 

noteman_slicer/editor.py

@@ -48,7 +48,7 @@ from . import bundle
 from .bundle import METADATA_FIELDS
 from .detect import deskew, detect_page
 from .pdf import Source, open_source, page_raster
-from .project import Cut, Project, default_path
+from .project import Cut, Project, open_project
 from .render import apply_levels
 
 PREVIEW_MAX = 1800  # display resolution; geometry stays normalised
@@ -356,17 +356,10 @@ class Editor(QMainWindow):
         discard = QPushButton("Toggle discard  (D)")
         discard.clicked.connect(self.view.toggle_discard)
         form.addRow(discard)
-        rect_row = QHBoxLayout()
-        fit = QPushButton("Auto-fit")
-        fit.setToolTip("Propose the content rectangle from the staff lines on this page")
-        fit.clicked.connect(lambda: self._autofit_rect(False))
-        fit_all = QPushButton("Auto-fit all")
-        fit_all.clicked.connect(lambda: self._autofit_rect(True))
-        reset = QPushButton("Reset")
+        reset = QPushButton("Reset content rectangle")
+        reset.setToolTip("Back to the rectangle detection proposed for this page")
         reset.clicked.connect(self._reset_rect)
-        for button in (fit, fit_all, reset):
-            rect_row.addWidget(button)
-        form.addRow("Content rect", rect_row)
+        form.addRow(reset)
         box.addWidget(page_box)
 
         meta_box = QGroupBox("Song")
@@ -482,25 +475,16 @@ class Editor(QMainWindow):
         }
         self.autosave.start()
 
-    def _autofit_rect(self, every_page: bool) -> None:
-        """Re-propose the content rectangle from the staff lines.
-
-        Detection does this for new projects; this is how a project made before
-        it existed, or one whose rectangle was dragged wrong, gets it back.
-        """
-        pages = range(len(self.project.pages)) if every_page else [self.index]
-        for i in pages:
-            # The preview is already deskewed, so the sweep is skipped.
-            proposal = detect_page(self._preview(i), skew=0.0)
-            self.project.pages[i].content_rect = proposal.content
-        self.view.redraw()
-        self._touched()
-        self.statusBar().showMessage(
-            f"content rectangle fitted on {len(list(pages))} page(s)", 2000
-        )
-
     def _reset_rect(self) -> None:
-        self.project.pages[self.index].content_rect = None
+        """Back to what detection proposed for this page.
+
+        Not to the whole page: the proposal is what excludes the scan-edge
+        junk, so clearing to full width would undo the thing the rectangle
+        exists for. The preview is already deskewed, so the sweep is skipped.
+        """
+        self.project.pages[self.index].content_rect = detect_page(
+            self._preview(self.index), skew=0.0
+        ).content
         self.view.redraw()
         self._touched()
 
@@ -524,7 +508,9 @@ class Editor(QMainWindow):
         QMessageBox.information(
             self,
             "Exported",
-            f"{out.name}\n{len(self.project.kept_slices())} slices, {size:.0f} KB",
+            f"{out.name}\n{len(self.project.kept_slices())} slices, {size:.0f} KB\n\n"
+            "This project is now spent — opening the PDF again starts a fresh "
+            "session from detection.",
         )
 
     def closeEvent(self, event) -> None:
@@ -532,27 +518,20 @@ class Editor(QMainWindow):
         super().closeEvent(event)
 
 
-def launch(pdf: Path, source_type=None) -> int:
+def launch(pdf: Path, source_type=None, resume: bool = False) -> int:
     app = QApplication(sys.argv[:1])
     source = open_source(pdf, source_type)
-    path = default_path(source.path)
 
-    if path.exists():
-        project = Project.load(path)
-        if project.source_changed():
-            QMessageBox.warning(
-                None,
-                "Source changed",
-                "The PDF has changed since these cuts were made.\n"
-                "Cuts may no longer line up with the music.",
-            )
-    else:
-        detections, heights = [], []
-        for i in range(len(source)):
-            gray = page_raster(source, i)
-            detections.append(detect_page(gray))
-            heights.append(gray.shape[0])
-        project = Project.from_detection(source.path, detections, heights)
+    # An exported project is spent: this opens a fresh session from detection
+    # rather than resuming decisions that have already been shipped.
+    project = open_project(source, resume=resume)
+    if project.path is not None and project.source_changed():
+        QMessageBox.warning(
+            None,
+            "Source changed",
+            "The PDF has changed since these cuts were made.\n"
+            "Cuts may no longer line up with the music.",
+        )
 
     window = Editor(source, project)
     window.resize(1500, 950)

noteman_slicer/project.py

@@ -113,6 +113,11 @@ class Project:
     levels: tuple[int, int] = (0, 255)
     metadata: dict[str, str] = field(default_factory=dict)
     path: Path | None = None
+    # Set once the song has been exported. A project is spent at that point:
+    # opening the PDF again starts a fresh session from detection rather than
+    # resuming, so a re-cut never begins from stale decisions. `--resume`
+    # overrides it when the old state really is wanted.
+    exported: bool = False
 
     # -- geometry helpers -------------------------------------------------
 
@@ -184,6 +189,7 @@ class Project:
             "v": FORMAT_VERSION,
             "source": self.source.name,
             "source_hash": self.source_hash,
+            "exported": self.exported,
             "content_rect": list(self.content_rect),
             "levels": list(self.levels),
             "metadata": self.metadata,
@@ -229,6 +235,7 @@ class Project:
             levels=tuple(data["levels"]),
             metadata=data.get("metadata", {}),
             path=path,
+            exported=data.get("exported", False),
         )
 
     def source_changed(self) -> bool:
@@ -236,6 +243,30 @@ class Project:
         return self.source.exists() and hash_file(self.source) != self.source_hash
 
 
+def open_project(source, *, resume: bool = False) -> Project:
+    """The project for a PDF: resumed, or a fresh session from detection.
+
+    A project that has been exported is spent. Opening the PDF again starts
+    over from detection rather than resuming, so a re-cut never inherits stale
+    decisions. `resume` overrides that when the old state really is wanted.
+    """
+    from .detect import detect_page
+    from .pdf import page_raster
+
+    path = default_path(source.path)
+    if path.exists():
+        existing = Project.load(path)
+        if resume or not existing.exported:
+            return existing
+
+    detections, heights = [], []
+    for i in range(len(source)):
+        gray = page_raster(source, i)
+        detections.append(detect_page(gray))
+        heights.append(gray.shape[0])
+    return Project.from_detection(source.path, detections, heights)
+
+
 def default_path(source: Path) -> Path:
     return Path(source).with_suffix(SUFFIX)
 

tests/test_editor.py

@@ -85,11 +85,15 @@ def main() -> int:
     editor.metadata["composer"].setText("trad.")
     assert project.metadata["title"] == "Ketun joululaulu"
 
-    # Content rectangle edits and reset.
+    # Content rectangle edits, and reset going back to detection's proposal for
+    # the page as it now stands — not to the whole page, which would undo the
+    # thing the rectangle exists for.
+    expected = detect_page(editor._preview(0), skew=0.0).content
     page.content_rect = (0.05, 0.02, 0.95, 0.98)
     assert project.page_content_rect(0) == (0.05, 0.02, 0.95, 0.98)
     editor._reset_rect()
-    assert project.page_content_rect(0) == project.content_rect
+    assert project.page_content_rect(0) == expected, (project.page_content_rect(0), expected)
+    assert project.page_content_rect(0) != (0.0, 0.0, 1.0, 1.0)
 
     # Autosave target, then a round-trip through disk.
     editor._save()

tests/test_project.py

@@ -67,6 +67,12 @@ def main() -> int:
     assert reloaded.source_hash == project.source_hash
     assert not reloaded.source_changed()
 
+    # A project is spent once exported: reopening starts fresh.
+    assert not reloaded.exported
+    reloaded.exported = True
+    reloaded.save()
+    assert Project.load(saved).exported
+
     # A PDF edited underneath must be reported, not silently re-cut.
     pdf.write_bytes(b"%PDF-1.7 different bytes entirely")
     assert reloaded.source_changed()

tests/test_render.py

@@ -16,7 +16,7 @@ sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
 from noteman_slicer import bundle  # noqa: E402
 from noteman_slicer.detect import detect_page  # noqa: E402
 from noteman_slicer.pdf import open_source, page_raster  # noqa: E402
-from noteman_slicer.project import Cut, Project  # noqa: E402
+from noteman_slicer.project import Cut, Project, default_path  # noqa: E402
 from noteman_slicer.render import (  # noqa: E402
     ALPHA_LEVELS,
     apply_levels,
@@ -151,8 +151,9 @@ def main() -> int:
         assert all(f in names for f in files)
 
     source.close()
-    for f in (pdf, out):
-        f.unlink()
+    # Exporting marks the project spent, which writes the project file.
+    for f in (pdf, out, default_path(pdf)):
+        f.unlink(missing_ok=True)
     tmp.rmdir()
     print("ok")
     return 0