Handle modified files where the case of the filename changed on case-insensitive filesystems (#6327)

* Find existing files with case insensitivity if filesystem is case insensitive
* Handle case change in folders
* Optimise to only test file system case sensitivity if the first query found nothing

This limits the overhead to new paths, and adds an extra query for new paths to windows installs

pkg/file/scan.go

@@ -443,7 +443,10 @@ func (s *scanJob) getFolderID(ctx context.Context, path string) (*models.FolderI
 		return &v, nil
 	}
 
-	ret, err := s.Repository.Folder.FindByPath(ctx, path)
+	// assume case sensitive when searching for the folder
+	const caseSensitive = true
+
+	ret, err := s.Repository.Folder.FindByPath(ctx, path, caseSensitive)
 	if err != nil {
 		return nil, err
 	}
@@ -473,7 +476,10 @@ func (s *scanJob) getZipFileID(ctx context.Context, zipFile *scanFile) (*models.
 		return &v, nil
 	}
 
-	ret, err := s.Repository.File.FindByPath(ctx, path)
+	// assume case sensitive when searching for the zip file
+	const caseSensitive = true
+
+	ret, err := s.Repository.File.FindByPath(ctx, path, caseSensitive)
 	if err != nil {
 		return nil, fmt.Errorf("getting zip file ID for %q: %w", path, err)
 	}
@@ -493,11 +499,26 @@ func (s *scanJob) handleFolder(ctx context.Context, file scanFile) error {
 		defer s.incrementProgress(file)
 
 		// determine if folder already exists in data store (by path)
-		f, err := s.Repository.Folder.FindByPath(ctx, path)
+		// assume case sensitive by default
+		f, err := s.Repository.Folder.FindByPath(ctx, path, true)
 		if err != nil {
 			return fmt.Errorf("checking for existing folder %q: %w", path, err)
 		}
 
+		// #1426 / #6326 - if folder is in a case-insensitive filesystem, then try
+		// case insensitive searching
+		// assume case sensitive if in zip
+		if f == nil && file.ZipFileID == nil {
+			caseSensitive, _ := file.fs.IsPathCaseSensitive(file.Path)
+
+			if !caseSensitive {
+				f, err = s.Repository.Folder.FindByPath(ctx, path, false)
+				if err != nil {
+					return fmt.Errorf("checking for existing folder %q: %w", path, err)
+				}
+			}
+		}
+
 		// if folder not exists, create it
 		if f == nil {
 			f, err = s.onNewFolder(ctx, file)
@@ -611,10 +632,18 @@ func (s *scanJob) onExistingFolder(ctx context.Context, f scanFile, existing *mo
 	// update if mod time is changed
 	entryModTime := f.ModTime
 	if !entryModTime.Equal(existing.ModTime) {
+		existing.Path = f.Path
 		existing.ModTime = entryModTime
 		update = true
 	}
 
+	// #6326 - update if path has changed - should only happen if case is
+	// changed and filesystem is case insensitive
+	if existing.Path != f.Path {
+		existing.Path = f.Path
+		update = true
+	}
+
 	// update if zip file ID has changed
 	fZfID := f.ZipFileID
 	existingZfID := existing.ZipFileID
@@ -647,15 +676,31 @@ func (s *scanJob) handleFile(ctx context.Context, f scanFile) error {
 	defer s.incrementProgress(f)
 
 	var ff models.File
+
 	// don't use a transaction to check if new or existing
 	if err := s.withDB(ctx, func(ctx context.Context) error {
 		// determine if file already exists in data store
+		// assume case sensitive when searching for the file to begin with
 		var err error
-		ff, err = s.Repository.File.FindByPath(ctx, f.Path)
+		ff, err = s.Repository.File.FindByPath(ctx, f.Path, true)
 		if err != nil {
 			return fmt.Errorf("checking for existing file %q: %w", f.Path, err)
 		}
 
+		// #1426 / #6326 - if file is in a case-insensitive filesystem, then try
+		// case insensitive search
+		// assume case sensitive if in zip
+		if ff == nil && f.ZipFileID != nil {
+			caseSensitive, _ := f.fs.IsPathCaseSensitive(f.Path)
+
+			if !caseSensitive {
+				ff, err = s.Repository.File.FindByPath(ctx, f.Path, false)
+				if err != nil {
+					return fmt.Errorf("checking for existing file %q: %w", f.Path, err)
+				}
+			}
+		}
+
 		if ff == nil {
 			// returns a file only if it is actually new
 			ff, err = s.onNewFile(ctx, f)
@@ -879,6 +924,7 @@ func (s *scanJob) handleRename(ctx context.Context, f models.File, fp []models.F
 			// #1426 - if file exists but is a case-insensitive match for the
 			// original filename, and the filesystem is case-insensitive
 			// then treat it as a move
+			// #6326 - this should now be handled earlier, and this shouldn't be necessary
 			if caseSensitive, _ := fs.IsPathCaseSensitive(other.Base().Path); !caseSensitive {
 				// treat as a move
 				missing = append(missing, other)
@@ -1026,7 +1072,8 @@ func (s *scanJob) onExistingFile(ctx context.Context, f scanFile, existing model
 	path := base.Path
 
 	fileModTime := f.ModTime
-	updated := !fileModTime.Equal(base.ModTime)
+	// #6326 - also force a rescan if the basename changed
+	updated := !fileModTime.Equal(base.ModTime) || base.Basename != f.Basename
 	forceRescan := s.options.Rescan
 
 	if !updated && !forceRescan {
@@ -1041,6 +1088,8 @@ func (s *scanJob) onExistingFile(ctx context.Context, f scanFile, existing model
 		logger.Infof("%s has been updated: rescanning", path)
 	}
 
+	// #6326 - update basename in case it changed
+	base.Basename = f.Basename
 	base.ModTime = fileModTime
 	base.Size = f.Size
 	base.UpdatedAt = time.Now()