restic: Compression leads to content mismatch after restore!

Output of restic version

This one works well:

/root/restic version
restic 0.13.1 compiled with go1.18 on linux/amd64

This one is current master compiled for compression tests:

/root/restic2 version
restic 0.13.1-dev (compiled manually) compiled with go1.18 on linux/amd64

How did you run restic exactly?

Simple backup with content comparing after restore.

source file:

dd if=/dev/sde of=/mnt/img1 bs=1M count=128

Current master WITH compression:

backup:

cat /mnt/img1 | /root/restic2 -r rest:http://dc15s3:8000/repo2/  --verbose backup --compression auto --stdin --stdin-filename img1 --password-file ./pass
open repository
repository 193651e2 opened (repo version 2) successfully, password is correct
lock repository
load index files
read data from stdin
start scan on [/img1]
start backup on [/img1]
scan finished in 2.952s: 1 files, 0 B

Files:           1 new,     0 changed,     0 unmodified
Dirs:            0 new,     0 changed,     0 unmodified
Data Blobs:     87 new
Tree Blobs:      1 new
Added to the repo: 128.006 MiB

processed 1 files, 128.000 MiB in 0:12
snapshot b727ac47 saved

/root/restic2 -r rest:http://dc15s3:8000/repo2/ --password-file ./pass snapshots
repository 193651e2 opened (repo version 2) successfully, password is correct
ID        Time                 Host        Tags        Paths
------------------------------------------------------------
b727ac47  2022-06-03 15:04:38  dc15                    /img1
------------------------------------------------------------
1 snapshots

restore:

/root/restic2 --verbose -r rest:http://dc15s3:8000/repo2/ dump b727ac47 /img1 --password-file ./pass | dd of=/mnt/img1_out 

compare:

md5sum /mnt/img1
d9a8853a50fedd618f3f361a913bac26  /mnt/img1
md5sum /mnt/img1_out
43f55c95aa1f3f951d62f917eedf2974  /mnt/img1_out

I use cat and stdin/stdout because i try to simulate backup and restore of block devices.

What backend/server/service did you use to store the repository?

i use rest-server in append only mode

Expected behavior

current tagged version WITHOUT compression works well:

backup:

cat /mnt/img1 | /root/restic -r rest:http://dc15s3:8000/repo1/  --verbose backup --stdin --stdin-filename img1 --password-file ./pass
open repository
repository 0376e109 opened successfully, password is correct
lock repository
load index files
read data from stdin
start scan on [/img1]
start backup on [/img1]
scan finished in 0.254s: 1 files, 0 B

Files:           1 new,     0 changed,     0 unmodified
Dirs:            0 new,     0 changed,     0 unmodified
Data Blobs:     92 new
Tree Blobs:      1 new
Added to the repo: 128.006 MiB

processed 1 files, 128.000 MiB in 0:01
snapshot 3a5bd550 saved

/root/restic -r rest:http://dc15s3:8000/repo1/ --password-file ./pass snapshots
repository 0376e109 opened successfully, password is correct
ID        Time                 Host        Tags        Paths
------------------------------------------------------------
3a5bd550  2022-06-03 14:58:28  dc15                    /img1
------------------------------------------------------------
1 snapshots

restore:

/root/restic --verbose -r rest:http://dc15s3:8000/repo1/ dump 3a5bd550 /img1 --password-file ./pass | dd of=/mnt/img1_out bs=1M

compare:

md5sum /mnt/img1
d9a8853a50fedd618f3f361a913bac26  /mnt/img1
md5sum /mnt/img1_out
d9a8853a50fedd618f3f361a913bac26  /mnt/img1_out

Actual behavior

content mismatch