prune: move additional option checks to repository

cmd/restic/cmd_prune.go

@@ -150,14 +150,6 @@ func runPrune(ctx context.Context, opts PruneOptions, gopts GlobalOptions, term
 	}
 	defer unlock()
 
-	if repo.Connections() < 2 {
-		return errors.Fatal("prune requires a backend connection limit of at least two")
-	}
-
-	if repo.Config().Version < 2 && opts.RepackUncompressed {
-		return errors.Fatal("compression requires at least repository format version 2")
-	}
-
 	if opts.UnsafeNoSpaceRecovery != "" {
 		repoID := repo.Config().ID
 		if opts.UnsafeNoSpaceRecovery != repoID {

cmd/restic/cmd_prune_integration_test.go

@@ -35,7 +35,7 @@ func testPruneVariants(t *testing.T, unsafeNoSpaceRecovery bool) {
 	}
 	t.Run("0"+suffix, func(t *testing.T) {
 		opts := PruneOptions{MaxUnused: "0%", unsafeRecovery: unsafeNoSpaceRecovery}
-		checkOpts := CheckOptions{ReadData: true, CheckUnused: true}
+		checkOpts := CheckOptions{ReadData: true, CheckUnused: !unsafeNoSpaceRecovery}
 		testPrune(t, opts, checkOpts)
 	})
 

internal/repository/prune.go

@@ -2,6 +2,7 @@ package repository
 
 import (
 	"context"
+	"fmt"
 	"math"
 	"sort"
 
@@ -87,6 +88,17 @@ type packInfoWithID struct {
 func PlanPrune(ctx context.Context, opts PruneOptions, repo restic.Repository, getUsedBlobs func(ctx context.Context, repo restic.Repository) (usedBlobs restic.CountedBlobSet, err error), printer progress.Printer) (PrunePlan, PruneStats, error) {
 	var stats PruneStats
 
+	if opts.UnsafeRecovery {
+		// prevent repacking data to make sure users cannot get stuck.
+		opts.MaxRepackBytes = 0
+	}
+	if repo.Connections() < 2 {
+		return PrunePlan{}, stats, fmt.Errorf("prune requires a backend connection limit of at least two")
+	}
+	if repo.Config().Version < 2 && opts.RepackUncompressed {
+		return PrunePlan{}, stats, fmt.Errorf("compression requires at least repository format version 2")
+	}
+
 	usedBlobs, err := getUsedBlobs(ctx, repo)
 	if err != nil {
 		return PrunePlan{}, stats, err