"No support for RAR VM program filter" error when extracting file using ArchiveIterator

[Niedzwiedzw]

    0. extracting from archive [JustPath("./downloads/Carved Brink Generic Assets Replacer (Stranger Mask and Corrupted Shade) ESL-25791-0-2-1557921142.rar")] (parent=NonEmpty { head: "./downloads/Carved Brink Generic Assets Replacer (Stranger Mask and Corrupted Shade) ESL-25791-0-2-1557921142.rar", tail: [] }, archive_paths=[
        "textures/falmershade/greatsword_n.dds",
        "textures/falmershade/sword.dds",
        "textures/falmershade/handaxe.dds",
        "textures/falmershade/sword_n.dds",
        "textures/falmershade/handaxe_n.dds",
        "textures/falmershade/warhammer.dds",
        "meshes/falmershade/arrowflight.nif",
        "textures/falmershade/helmet.dds",
        "textures/strangermask/mask.dds",
        "meshes/falmershade/falmershade.nif",
        "textures/falmershade/helmet_n.dds",
        "textures/falmershade/battleaxe.dds",
        "textures/falmershade/mace.dds",
        "textures/falmershade/battleaxe_n.dds",
        "textures/falmershade/mace_n.dds",
        "textures/falmershade/bow.dds",
        "textures/falmershade/quiver.dds",
        "Carved Brink Falmer Shade.esp",
        "textures/falmershade/quiver_n.dds",
        "textures/falmershade/bow_n.dds",
        "textures/falmershade/dagger.dds",
        "textures/falmershade/scabbard.dds",
        "textures/falmershade/dagger_n.dds",
        "textures/falmershade/scabbard_n.dds",
        "textures/falmershade/greatsword.dds",
        "textures/falmershade/shield.dds",
    ])
    1. when unpacking files from archive [CompressTools]
    2. reading multiple paths from archive
    3. when reading: "textures/falmershade/greatsword_n.dds" size=5592560
    4. Extraction error: 'No support for RAR VM program filter'
    ```

[otavio]

Hi @Niedzwiedzw, thanks for the detailed report.

The message 'No support for RAR VM program filter' comes from libarchive's classic RAR (v4) decoder at archive_read_support_format_rar.c:3767 — it fires when the archive contains a RAR‑VM program whose crc32(prog) | (len<<32) fingerprint isn't one of the five libarchive supports (delta, e8, e8e9, rgb, audio). This usually means the archive was produced by a WinRAR version whose VM bytecode differs by at least one byte from what libarchive has hardcoded.

I spent some time trying to reproduce the error with rar 6.21 on libarchive 3.7.4 (forcing various -mc* filters on x86, DDS, BMP, WAV content, plus the libarchive test corpus and taviso/rarvmtools) and couldn't get a modern toolchain to emit a VM program with a fingerprint libarchive misses — current WinRAR's bytecode still matches the hardcoded set. So to add a regression test I need a fixture that actually triggers this on your archive.

Could you attach a minimally-reduced RAR to this issue? Ideally:

• Open the failing archive (…25791-0-2-1557921142.rar) with WinRAR and extract a single small file from it (e.g. the smallest .dds).
• Re‑pack just that one file into a new .rar using the same WinRAR version you used originally, with default settings (-ma4 if WinRAR 6+ so it stays RAR4).
• Confirm on your end that compress_tools::ArchiveIterator still reports 'No support for RAR VM program filter' on the reduced archive.
• Attach it here. A few hundred KB is fine.

That gives us a self-contained fixture we can ship under tests/fixtures/ and assert the expected error on. Thanks!