Geeqie FileData leaks identified by refcount debugging mode

[xsdg]

Setup (please complete the following information):

• Distribution: [e.g. Ubuntu] Debian
• Distribution release: [e.g. 20.04] Sid
• Geeqie version [geeqie --version]: git a1ef50f

Describe the bug
FileData leaks with the following refcount sequences:

FileData dump start
/path/to/.../build/src/../../src/main.cc:528 exit_program_final

2
2
2    /tmp/tmp.QUXpoOpmo4/container_dir/images_dir/DSCF0253.MPO
    r -> 2 @ ../src/view-file/view-file-list.cc:845
    r -> 3 @ ../src/image.cc:753
    r -> 4 @ ../src/image-load.cc:298
    r -> 5 @ ../src/filecache.cc:168
    r -> 6 @ ../src/filedata/filedata.cc:372
    u -> 5 @ ../src/filedata/filelist.cc:356
    r -> 6 @ ../src/filecache.cc:168
    u -> 5 @ ../src/image-load.cc:275
    r -> 6 @ ../src/filedata/filedata.cc:372
    u -> 5 @ ../src/filedata/filelist.cc:356
    r -> 6 @ ../src/filedata/filedata.cc:372
    u -> 5 @ ../src/filedata/filelist.cc:356
    u -> 4 @ ../src/view-file/view-file-list.cc:154
    u -> 3 @ ../src/filedata/filelist.cc:356
    u -> 2 @ ../src/image.cc:690
3    /tmp/tmp.QUXpoOpmo4/container_dir/images_dir/Chimera-AV1-8bit-768x432-1160kbps-162.avif
    r -> 2 @ ../src/view-file/view-file-list.cc:845
    r -> 3 @ ../src/image.cc:1101
    r -> 4 @ ../src/image-load.cc:298
    r -> 5 @ ../src/filecache.cc:168
    r -> 6 @ ../src/filedata/filedata.cc:2800
    r -> 7 @ ../src/filedata/filedata.cc:372
    r -> 8 @ ../src/view-file/view-file-list.cc:1238
    u -> 7 @ ../src/filedata/filelist.cc:356
    u -> 6 @ ../src/filedata/filelist.cc:356
    u -> 5 @ ../src/image-load.cc:275
    r -> 6 @ ../src/image-load.cc:298
    r -> 7 @ ../src/filecache.cc:168
    u -> 6 @ ../src/image-load.cc:275
    r -> 7 @ ../src/filedata/filedata.cc:372
    r -> 8 @ ../src/filedata/filedata.cc:1157
    u -> 7 @ ../src/filedata/filelist.cc:356
    u -> 6 @ ../src/command-line-handling.cc:657
    r -> 7 @ ../src/filedata/filedata.cc:372
    r -> 8 @ ../src/view-file/view-file-list.cc:1238
    u -> 7 @ ../src/filedata/filelist.cc:356
    u -> 6 @ ../src/filedata/filelist.cc:356
    u -> 5 @ ../src/view-file/view-file-list.cc:154
    u -> 4 @ ../src/filedata/filelist.cc:356
    u -> 3 @ ../src/filedata/filedata.cc:2839
    u -> 2 @ ../src/image.cc:1100
    r -> 3 @ ../src/filedata/filedata.cc:372
    r -> 4 @ ../src/filedata/filedata.cc:1157
    u -> 3 @ ../src/filedata/filelist.cc:356
    r -> 4 @ ../src/filedata/filedata.cc:372
    r -> 5 @ ../src/view-file/view-file-list.cc:845
    r -> 6 @ ../src/image.cc:1101
    r -> 7 @ ../src/filedata/filedata.cc:2800
    r -> 8 @ ../src/filedata/filedata.cc:372
    r -> 9 @ ../src/view-file/view-file-list.cc:1238
    u -> 8 @ ../src/filedata/filelist.cc:356
    u -> 7 @ ../src/filedata/filelist.cc:356
    r -> 8 @ ../src/filedata/filedata.cc:372
    r -> 9 @ ../src/filedata/filedata.cc:1157
    u -> 8 @ ../src/filedata/filelist.cc:356
    u -> 7 @ ../src/command-line-handling.cc:657
    r -> 8 @ ../src/filedata/filedata.cc:372
    r -> 9 @ ../src/view-file/view-file-list.cc:1238
    u -> 8 @ ../src/filedata/filelist.cc:356
    u -> 7 @ ../src/filedata/filelist.cc:356
    u -> 6 @ ../src/view-file/view-file-list.cc:154
    u -> 5 @ ../src/filedata/filelist.cc:356
    u -> 4 @ ../src/filedata/filedata.cc:2839
    u -> 3 @ ../src/image.cc:1100
FileData dump end

To reproduce

$meson setup -D unit_tests=enabled -D fd_verbose_debug=enabled build
$ninja -C build && meson test -v -C build --suite filedata

Expected behavior
No FileData leaks

[xsdg]

Okay, I disabled the file cache (multiplied max size by 0 in image.cc:image_get_cache()) and the refcounts on both files dropped. The MPO filedata was freed, and the avif file was still around with a refcount of 2 rather than 3:

FileData dump start
/path/to/.../build/src/../../src/main.cc:528 exit_program_final

1
1
2    /tmp/tmp.JcA69ADEsX/container_dir/images_dir/Chimera-AV1-8bit-768x432-1160kbps-162.avif
    r -> 2 @ ../src/view-file/view-file-list.cc:845
    r -> 3 @ ../src/image.cc:1101
    r -> 4 @ ../src/image-load.cc:298
    r -> 5 @ ../src/filecache.cc:168
    r -> 6 @ ../src/filedata/filedata.cc:2800
    r -> 7 @ ../src/filedata/filedata.cc:372
    r -> 8 @ ../src/view-file/view-file-list.cc:1238
    u -> 7 @ ../src/filedata/filelist.cc:356
    u -> 6 @ ../src/filedata/filelist.cc:356
    u -> 5 @ ../src/image-load.cc:275
    r -> 6 @ ../src/image-load.cc:298
    r -> 7 @ ../src/filecache.cc:168
    u -> 6 @ ../src/filecache.cc:78
    u -> 5 @ ../src/image-load.cc:275
    r -> 6 @ ../src/filedata/filedata.cc:372
    r -> 7 @ ../src/filedata/filedata.cc:1157
    u -> 6 @ ../src/filedata/filelist.cc:356
    u -> 5 @ ../src/command-line-handling.cc:657
    r -> 6 @ ../src/filedata/filedata.cc:372
    r -> 7 @ ../src/view-file/view-file-list.cc:1238
    u -> 6 @ ../src/filedata/filelist.cc:356
    u -> 5 @ ../src/filedata/filelist.cc:356
    r -> 6 @ ../src/image-load.cc:298
    r -> 7 @ ../src/filecache.cc:168
    u -> 6 @ ../src/filecache.cc:78
    u -> 5 @ ../src/image-load.cc:275
    u -> 4 @ ../src/view-file/view-file-list.cc:154
    u -> 3 @ ../src/filedata/filelist.cc:356
    u -> 2 @ ../src/filedata/filedata.cc:2839
    u -> 1 @ ../src/image.cc:1100
    r -> 2 @ ../src/filedata/filedata.cc:372
    r -> 3 @ ../src/filedata/filedata.cc:1157
    u -> 2 @ ../src/filedata/filelist.cc:356
    r -> 3 @ ../src/filedata/filedata.cc:372
    r -> 4 @ ../src/view-file/view-file-list.cc:845
    r -> 5 @ ../src/image.cc:1101
    r -> 6 @ ../src/image-load.cc:298
    r -> 7 @ ../src/filedata/filedata.cc:2800
    r -> 8 @ ../src/filedata/filedata.cc:372
    r -> 9 @ ../src/view-file/view-file-list.cc:1238
    u -> 8 @ ../src/filedata/filelist.cc:356
    u -> 7 @ ../src/filedata/filelist.cc:356
    u -> 6 @ ../src/image-load.cc:275
    r -> 7 @ ../src/image-load.cc:298
    r -> 8 @ ../src/filecache.cc:168
    u -> 7 @ ../src/filecache.cc:78
    u -> 6 @ ../src/image-load.cc:275
    r -> 7 @ ../src/filedata/filedata.cc:372
    r -> 8 @ ../src/filedata/filedata.cc:1157
    u -> 7 @ ../src/filedata/filelist.cc:356
    u -> 6 @ ../src/command-line-handling.cc:657
    r -> 7 @ ../src/filedata/filedata.cc:372
    r -> 8 @ ../src/view-file/view-file-list.cc:1238
    u -> 7 @ ../src/filedata/filelist.cc:356
    u -> 6 @ ../src/filedata/filelist.cc:356
    r -> 7 @ ../src/image-load.cc:298
    r -> 8 @ ../src/filecache.cc:168
    u -> 7 @ ../src/filecache.cc:78
    u -> 6 @ ../src/image-load.cc:275
    u -> 5 @ ../src/view-file/view-file-list.cc:154
    u -> 4 @ ../src/filedata/filelist.cc:356
    u -> 3 @ ../src/filedata/filedata.cc:2839
    u -> 2 @ ../src/image.cc:1100
FileData dump end