Could not compile in release. File name too long.

[coolcatcoder]

I tried to compile this repository https://github.com/coolcatcoder/mind_control_retry with cargo run --release.
(This does not happen in debug, only release.)

I expected it to compile.

Instead, this happened:

error: could not write output to /home/coolcatcoder/Documents/GitHub/mind_control_retry/target/release/deps/230fb44afa6e3556-8bcaa95a9ca3f52.bevy_transform_interpolation-bbcabe0d7d92346f.bevy_transform_interpolation.12ba7750790b6058-cgu.0.rcgu.o.rcgu.o: File name too long

Meta

rustc --version --verbose:

rustc 1.92.0-nightly (695857bc3 2025-10-21)
binary: rustc
commit-hash: 695857bc3f72ec4f59c79f323460fe488c38a53f
commit-date: 2025-10-21
host: x86_64-unknown-linux-gnu
release: 1.92.0-nightly
LLVM version: 21.1.3

[bjorn3]

At least one issue is that the .rcgu.o extension gets appended twice, but even with that the filename is only 220 characters long. Linux should be able to handle individual path components of 255 bytes and even longer total paths. Are you perhaps using a fuse filesystem like ecryptfs for your home directory?

(removing S-has-mcve as this project is not a minimal reproducer)

[bjorn3]

I can reproduce the extension duplication with echo 'fn main() {}' | rustc - -Csave-temps -Copt-level=3 -Clto=thin, but not with fat LTO.

Edit: Looks like thin LTO uses the filename of the original object file for the module name of imported bitcode (eg foo-abc.foo.def-cgu.0.rcgu.o. This is then mangled the same as local modules when generating the output filename (eg local-ghi.foo-abc.foo.def-cgu.0.rcgu.o.rcgu.o)

[coolcatcoder]

Are you perhaps using a fuse filesystem like ecryptfs for your home directory?

I'm not very familiar with filesystems. If I understand what you are asking for currently, I'm using Ext4.

[bjorn3]

Are you using an encrypted home directory? That often uses something like ecryptfs as overlay on top of your base filesystem like ext4. What does cat /proc/mounts | grep fuse | grep -v /run/user show?

[coolcatcoder]

I am not using an encrypted home directory if I recall correctly.
The output of that command is: fusectl /sys/fs/fuse/connections fusectl rw,nosuid,nodev,noexec,relatime 0 0

[bjorn3]

Weird. No clue why it complains about a 240 byte path already then.