From d8dcbc89d11b43e9221456e6ee08da13844ab703 Mon Sep 17 00:00:00 2001
From: Alexander Neumann <alexander@bumpern.de>
Date: Mon, 5 Mar 2018 20:17:40 +0100
Subject: [PATCH] lock: Ignore invalid lock file

This commit fixes a bug introduced in
e9ea26884739a218bbab0248b634d2821be9c3ea: When an invalid lock is
encountered (e.g. if the file is empty), the code used to ignore that,
but now returns the error.

Now, invalid files are ignored for the normal lock check, and removed
when `restic unlock --remove-all` is run.

Closes #1652
---
 internal/restic/lock.go | 25 +++++++++----------------
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/internal/restic/lock.go b/internal/restic/lock.go
index d3e5edc57..3e3a27a6b 100644
--- a/internal/restic/lock.go
+++ b/internal/restic/lock.go
@@ -138,13 +138,15 @@ func (l *Lock) fillUserInfo() error {
 // non-exclusive lock is to be created, an error is only returned when an
 // exclusive lock is found.
 func (l *Lock) checkForOtherLocks(ctx context.Context) error {
-	return eachLock(ctx, l.repo, func(id ID, lock *Lock, err error) error {
+	return l.repo.List(ctx, LockFile, func(id ID, size int64) error {
 		if l.lockID != nil && id.Equal(*l.lockID) {
 			return nil
 		}
 
-		// ignore locks that cannot be loaded
+		lock, err := LoadLock(ctx, l.repo, id)
 		if err != nil {
+			// ignore locks that cannot be loaded
+			debug.Log("ignore lock %v: %v", id, err)
 			return nil
 		}
 
@@ -160,17 +162,6 @@ func (l *Lock) checkForOtherLocks(ctx context.Context) error {
 	})
 }
 
-func eachLock(ctx context.Context, repo Repository, f func(ID, *Lock, error) error) error {
-	return repo.List(ctx, LockFile, func(id ID, size int64) error {
-		lock, err := LoadLock(ctx, repo, id)
-		if err != nil {
-			return err
-		}
-
-		return f(id, lock, err)
-	})
-}
-
 // createLock acquires the lock by creating a file in the repository.
 func (l *Lock) createLock(ctx context.Context) (ID, error) {
 	id, err := l.repo.SaveJSONUnpacked(ctx, LockFile, l)
@@ -283,9 +274,11 @@ func LoadLock(ctx context.Context, repo Repository, id ID) (*Lock, error) {
 
 // RemoveStaleLocks deletes all locks detected as stale from the repository.
 func RemoveStaleLocks(ctx context.Context, repo Repository) error {
-	return eachLock(ctx, repo, func(id ID, lock *Lock, err error) error {
-		// ignore locks that cannot be loaded
+	return repo.List(ctx, LockFile, func(id ID, size int64) error {
+		lock, err := LoadLock(ctx, repo, id)
 		if err != nil {
+			// ignore locks that cannot be loaded
+			debug.Log("ignore lock %v: %v", id, err)
 			return nil
 		}
 
@@ -299,7 +292,7 @@ func RemoveStaleLocks(ctx context.Context, repo Repository) error {
 
 // RemoveAllLocks removes all locks forcefully.
 func RemoveAllLocks(ctx context.Context, repo Repository) error {
-	return eachLock(ctx, repo, func(id ID, lock *Lock, err error) error {
+	return repo.List(ctx, LockFile, func(id ID, size int64) error {
 		return repo.Backend().Remove(context.TODO(), Handle{Type: LockFile, Name: id.String()})
 	})
 }