backup: use unified FindFilteredSnapshot

cmd/restic/cmd_backup.go

@@ -505,27 +505,20 @@ func collectTargets(opts BackupOptions, args []string) (targets []string, err er
 // parent returns the ID of the parent snapshot. If there is none, nil is
 // returned.
 func findParentSnapshot(ctx context.Context, repo restic.Repository, opts BackupOptions, targets []string, timeStampLimit time.Time) (parentID *restic.ID, err error) {
-	// Force using a parent
-	if !opts.Force && opts.Parent != "" {
-		id, err := restic.FindSnapshot(ctx, repo.Backend(), opts.Parent)
-		if err != nil {
-			return nil, errors.Fatalf("invalid id %q: %v", opts.Parent, err)
-		}
-
-		parentID = &id
+	if opts.Force {
+		return nil, nil
 	}
 
-	// Find last snapshot to set it as parent, if not already set
-	if !opts.Force && parentID == nil {
-		id, err := restic.FindLatestSnapshot(ctx, repo.Backend(), repo, targets, []restic.TagList{}, []string{opts.Host}, &timeStampLimit)
-		if err == nil {
-			parentID = &id
-		} else if err != restic.ErrNoSnapshotFound {
-			return nil, err
-		}
+	snName := opts.Parent
+	if snName == "" {
+		snName = "latest"
 	}
-
-	return parentID, nil
+	id, err := restic.FindFilteredSnapshot(ctx, repo.Backend(), repo, []string{opts.Host}, []restic.TagList{}, targets, &timeStampLimit, snName)
+	// Snapshot not found is ok if no explicit parent was set
+	if opts.Parent == "" && errors.Is(err, restic.ErrNoSnapshotFound) {
+		err = nil
+	}
+	return &id, err
 }
 
 func runBackup(ctx context.Context, opts BackupOptions, gopts GlobalOptions, term *termstatus.Terminal, args []string) error {

cmd/restic/cmd_dump.go

@@ -139,7 +139,7 @@ func runDump(ctx context.Context, opts DumpOptions, gopts GlobalOptions, args []
 		}
 	}
 
-	id, err := restic.FindFilteredSnapshot(ctx, repo.Backend(), repo, opts.Paths, opts.Tags, opts.Hosts, snapshotIDString)
+	id, err := restic.FindFilteredSnapshot(ctx, repo.Backend(), repo, opts.Paths, opts.Tags, opts.Hosts, nil, snapshotIDString)
 	if err != nil {
 		Exitf(1, "failed to find snapshot: %v", err)
 	}

cmd/restic/cmd_ls.go

@@ -210,7 +210,7 @@ func runLs(ctx context.Context, opts LsOptions, gopts GlobalOptions, args []stri
 		}
 	}
 
-	id, err := restic.FindFilteredSnapshot(ctx, snapshotLister, repo, opts.Hosts, opts.Tags, opts.Paths, args[0])
+	id, err := restic.FindFilteredSnapshot(ctx, snapshotLister, repo, opts.Hosts, opts.Tags, opts.Paths, nil, args[0])
 	if err != nil {
 		return err
 	}

cmd/restic/cmd_restore.go

@@ -131,7 +131,7 @@ func runRestore(ctx context.Context, opts RestoreOptions, gopts GlobalOptions, a
 		}
 	}
 
-	id, err := restic.FindFilteredSnapshot(ctx, repo.Backend(), repo, opts.Hosts, opts.Tags, opts.Paths, snapshotIDString)
+	id, err := restic.FindFilteredSnapshot(ctx, repo.Backend(), repo, opts.Hosts, opts.Tags, opts.Paths, nil, snapshotIDString)
 	if err != nil {
 		Exitf(1, "failed to find snapshot %q: %v", snapshotIDString, err)
 	}