[Jammy123-prog]

Problem

PPOCRLabel crashes (exits without any dialog) when the user deletes an image while the "auto save unsaved changes" option is enabled (and also whenever there are unsaved changes on the deleted image).

Root cause

After the image is moved to the trash, deleteImg() calls importDirImages(..., isDelete=True), which first goes through mayContinue() → saveFile(). At that moment self.filePath still points to the file that has just been deleted, so _saveFile() crashes in cv2.imdecode(np.fromfile(...)):

Traceback (most recent call last):
  File "PPOCRLabel.py", line 2907, in deleteImg
    self.importDirImages(self.lastOpenDir, isDelete=True)
  File "PPOCRLabel.py", line 2687, in importDirImages
    if not self.mayContinue() or not dirpath:
  File "PPOCRLabel.py", line 2935, in mayContinue
    self.saveFile()
  File "PPOCRLabel.py", line 2814, in saveFile
    self._saveFile(img_idx, mode=mode)
  File "PPOCRLabel.py", line 2835, in _saveFile
    np.fromfile(self.filePath, dtype=np.uint8), cv2.IMREAD_COLOR
FileNotFoundError: [Errno 2] No such file or directory: '...jpg'

Fix (13 lines, no behaviour change for normal saves)

1. saveFile(): skip saving (with a warning log) when the target file no longer exists on disk.
2. deleteImg(): drop the stale reference (self.filePath = None, self.dirty = False) before reloading the directory, so nothing can re-read the deleted image.

Verification

Reproduced the exact call chain in a regression test (open dir → mark dirty → remove file → saveFile(mode="Auto") + metadata saves):

• before the fix: hard crash (exit 139)
• after the fix: all steps pass, Label.txt / Cache.cach / fileState.txt are written correctly

Manual GUI test on Windows 11 + PaddleOCR 3.7.0 + custom det/rec models: deleting images no longer crashes the app.

中文说明

问题：开启"自动保存未提交变更"后删除图片，程序直接闪退。

根因：图片移入回收站后，deleteImg() → importDirImages(isDelete=True) → mayContinue() → saveFile() 链路仍持有 self.filePath（已删除路径），cv2.imdecode(np.fromfile(...)) 抛 FileNotFoundError 崩溃。

修复：① saveFile() 增加文件存在性检查，文件不存在则跳过并记录 warning；② deleteImg() 删除成功后立即清空 filePath 引用并复位 dirty 标志。共 13 行新增，不影响正常保存逻辑。已通过回归测试与 GUI 手工验证。

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Follow-up (2nd commit): jump to the next unlabeled image after deletion

The crash fix clears self.filePath before importDirImages() rescans the folder, so openNextImg() falls back to selecting the very first image of the directory — the annotator loses their position in the list after every deletion.

Restore position-aware navigation and improve it:

• deleteImg() records the index of the deleted image and passes it to importDirImages(..., isDelete=True, deleteIdx=...).
• importDirImages() maps that index onto the rescanned list (the same index then points at the image that followed the deleted one) and asks openNextImg() to prefer an unlabeled target.
• openNextImg(preferUnlabeled=True) skips forward to the first image whose validFilestate() is False — the next image that still needs annotation. If all following images are already labeled, it keeps the previous fallback (the image right after the deleted one, or the previous one when the last image was deleted).

Verified with three scenarios (3-image folder):

1. delete 1st, 2nd already labeled → 3rd is selected
2. delete 1st, rest labeled → 2nd is selected (fallback)
3. delete last → previous is selected

补充说明（第二个提交）：删除后跳转到下一张未标注图片

崩溃修复会先清空 self.filePath，导致重扫列表后 openNextImg() 总是选中目录里的第一张图片，标注位置丢失。本提交记录被删图片的索引并传递给重扫逻辑，删除后自动跳到下一张未标注（validFilestate() 为 False）的图片；若后续均已标注则回退为紧邻的下一张；删除最后一张时回退为前一张。三个场景回归测试全部通过。