fails to unpack an image if symlink to a directory was replaced with a new dir and its old target removed

[uvlad7]

build this (docker build . --network host --tag 'base:42')

FROM buildpack-deps:bookworm

RUN apt-get update -qq -y --allow-unauthenticated && \
    wget https://repo.percona.com/apt/percona-release_latest.bookworm_all.deb && \
    apt install -y ./percona-release_latest.bookworm_all.deb && \
    rm percona-release_latest.bookworm_all.deb && \
    percona-release setup ps57 && apt install -y libperconaserverclient20-dev

run diffoci diff --semantic --report-dir diff docker://base:42 docker://buildpack-deps:bookworm

INFO[0000] Target platforms: [linux/amd64]                                                                                                                                                                                                                                                 
INFO[0000] Loading image "docker.io/library/base:42" from "docker" 
docker.io/library/base:42                       saved
Importing       elapsed: 8.5 s  total:   0.0 B  (0.0 B/s)
INFO[0022] Loading image "docker.io/library/buildpack-deps:bookworm" from "docker" 
docker.io/library/buildpack deps:bookwor        saved
Importing       elapsed: 7.7 s  total:   0.0 B  (0.0 B/s)
WARN[0038] Layer length mismatch (5 vs 4), squashing for comparison (EXPERIMENTAL) 
ERRO[0045] failed to load layer (input-0): mkdir /home/vladimir/profit/kanibug/diff/input-0/usr/include/mysql: file exists 

$ file /home/vladimir/profit/kanibug/diff/input-0/usr/include/mysql                                                                                                                                                                                      
/home/vladimir/profit/kanibug/diff/input-0/usr/include/mysql: symbolic link to mariadb

Seems to be similar to this issue, but I wasn't able to reproduce it on these examples

[henrahmagix]

I get the same here, can't use --report-dir

$ docker images
REPOSITORY                            TAG                                        IMAGE ID       CREATED         SIZE
nginx                                 alpine                                     96868d9fa38f   5 weeks ago     49.7MB
ruby                                  3.4.3-alpine                               6b368c3813be   6 weeks ago     76.1MB
moby/buildkit                         buildx-stable-1                            e334cc02300c   2 months ago    210MB
redis                                 7.0                                        2c96e8092504   12 months ago   131MB
postgres                              14.5                                       3c326264b599   2 years ago     357MB

$ rm -rf ~/diff

$ diffoci diff --platform=linux/amd64 --semantic --report-dir=~/diff docker://nginx:alpine docker://ruby:3.4.3-alpine
INFO[0000] Target platforms: [linux/amd64]
INFO[0000] Loading image "docker.io/library/nginx:alpine" from "docker"
docker.io/library/nginx:alpine                  saved
Importing       elapsed: 0.4 s  total:   0.0 B  (0.0 B/s)
INFO[0000] Loading image "docker.io/library/ruby:3.4.3-alpine" from "docker"
docker.io/library/ruby:3.4.3 alpine             saved
Importing       elapsed: 0.5 s  total:   0.0 B  (0.0 B/s)
WARN[0001] Layer length mismatch (8 vs 4), squashing for comparison (EXPERIMENTAL)
TYPE    NAME                  INPUT-0    INPUT-1
Cfg     ctx:/config/config    ?          ?
ERRO[0001] failed to load layer (input-1): symlink /bin/busybox /Users/henry/diff/input-1/bin/base64: file exists

but I can otherwise use this helpful tool without --report-dir:

$ diffoci diff --platform=linux/amd64 --semantic docker://nginx:alpine docker://ruby:3.4.3-alpine | head
INFO[0000] Target platforms: [linux/amd64]
INFO[0000] Loading image "docker.io/library/nginx:alpine" from "docker"
docker.io/library/nginx:alpine                  saved
Importing       elapsed: 0.4 s  total:   0.0 B  (0.0 B/s)
INFO[0000] Loading image "docker.io/library/ruby:3.4.3-alpine" from "docker"
docker.io/library/ruby:3.4.3 alpine             saved
Importing       elapsed: 0.5 s  total:   0.0 B  (0.0 B/s)
WARN[0001] Layer length mismatch (8 vs 4), squashing for comparison (EXPERIMENTAL)
TYPE     NAME                                 INPUT-0                                                                                                                                     INPUT-1
Cfg      ctx:/config/config                   ?                                                                                                                                           ?
Layer    ctx:/layer                           length mismatch (2260 vs 4105)
Layer    ctx:/layer                           name "usr/share/" appears 3 times in input 0, 1 times in input 1
Layer    ctx:/layer                           name "usr/share/zoneinfo/Asia/Calcutta" only appears in input 0
Layer    ctx:/layer                           name "etc/ssl/certs/ca-cert-Amazon_Root_CA_1.pem" only appears in input 0
Layer    ctx:/layer                           name "usr/share/X11/locale/cs_CZ.UTF-8/XI18N_OBJS" only appears in input 0
Layer    ctx:/layer                           name "usr/share/X11/locale/georgian-academy/XLC_LOCALE" only appears in input 0
Layer    ctx:/layer                           name "usr/share/zoneinfo/America/Argentina/La_Rioja" only appears in input 0
Layer    ctx:/layer                           name "usr/share/zoneinfo/America/Atka" only appears in input 0

It'd be nice to be able to use --report-dir so I can investigate file differences 🙌

[mzihlmann]

@uvlad7 what a small world. I see that the original issue led you here to investigate, only to hit another obstacle.
Anyways, there you go again 😄