[1.94+] Build Error when absolut path includes Whitespaces

[RNO-HMRKG]

Some Crates needing the gcc fail to build from Rust 1.94 onwards. I am unsure where the problem is but I think I know what it it.

I tried the default project init after using cargo init . All I did was add getrandom crate to cargo.toml.

[package]
name = "rs_test"
version = "0.1.0"
edition = "2024"

[dependencies]
getrandom = "*"

Running cargo run yields the following error.

   Compiling getrandom v0.4.2
error: dlltool could not create import library with C:\mingw64\bin\dlltool.exe -d C:\Users\NAME\Desktop\Code Workspace\rs_test\target\debug\deps\rustcuRynkC\bcryptprimitives.dll_imports.def -D bcryptprimitives.dll -l C:\Users\NAME\Desktop\Code Workspace\rs_test\target\debug\deps\rustcuRynkC\bcryptprimitives.dll_imports.lib -m i386:x86-64 -f --64 --no-leading-underscore --temp-prefix C:\Users\NAME\Desktop\Code Workspace\rs_test\target\debug\deps\rustcuRynkC\bcryptprimitives.dll:
       
       Assembler messages:␍
       Error: can't open Workspace\rs_test\target\debug\deps\rustcuRynkC\bcryptprimitives.dllh.o for reading: No such file or directory␍
       C:\Users\NAME\Desktop\Code: Error: can't open Workspace\rs_test\target\debug\deps\rustcuRynkC\bcryptprimitives.dllh.s for reading: No such file or directory␍
       C:\mingw64\bin\dlltool.exe: C:\mingw64\bin\as exited with status 1␍
       C:\mingw64\bin\dlltool.exe: failed to open temporary head file: C:\Users\NAME\Desktop\Code Workspace\rs_test\target\debug\deps\rustcuRynkC\bcryptprimitives.dllh.o: No such file or directory␍
       

error: could not compile `getrandom` (lib) due to 1 previous error 

The project root lies at C:\Users\NAME\Desktop\Code Workspace\rs_test. As you can see, there is one whitespace in it. It looks like this is a problem in the build pipeline since the Error message splits the path at one point. The same project builds just fine in Rust 1.93.

Meta

OS: Win11 64bit
target: x86_64-pc-windows-gnu
gcc: MinGW-W64 x86_64-ucrt-posix-seh, built by Brecht Sanders, r3 14.2.0
rustc --version --verbose:

rustc 1.94.1 (e408947bf 2026-03-25)
binary: rustc
commit-hash: e408947bfd200af42db322daf0fadfe7e26d3bd1
commit-date: 2026-03-25
host: x86_64-pc-windows-gnu
release: 1.94.1
LLVM version: 21.1.8

Since multiple Crates are affected, this likely is a general problem.

Affected crates so far:

• getrandom
• windows-sys

Larger Crates dependent on those and therefor currently failing to build too.

• aws-lc-rs (and aws-lc-sys)
• rustls
• lettre
• reqwest
• sqlx
• actix-web
• ring
• log4rs
• rand
• uuid
• tokio
• hyper

[nivekithan]

Incase it's helpful for triaging the bug.

This bug does not reproduce on linux machine

• my working directory

pwd 
# /home/nivekithan/code/test rust issue/reproduce

• my rustc version

rustc --version
# rustc 1.95.0 (59807616e 2026-04-14)

• My cargo toml file

[package]
name = "reproduce"
version = "0.1.0"
edition = "2024"

[dependencies]
getrandom = "*"

• and running cargo run gives output

    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.01s
     Running `target/debug/reproduce`
Hello, world!

So maybe this issue is present only on windows machine ?

[RNO-HMRKG]

I just verified, that the problem is gone when removing all whitespaces.

I also guess that this is something regarding the invocation of the mingw lib (windows). However the occurence of the problem above only depends on the rustc version, not the mingw version. Likely the invocation of some mingw utils by the rust compiler was reworked in 1.94 and now does not correctly escape command line arguments anymore.

[rustbot]

Assigning P-critical (discussion on Zulip).

[ChrisDenton]

The last change to that part of the code was in 1.93 (and even that doesn't seem related): https://github.com/rust-lang/rust/blame/2f43fe430374fce8c75d477bdb78715d5c0349c4/compiler/rustc_codegen_ssa/src/back/archive.rs#L187

Could it be that new versions are picking up a different dlltool.exe somehow? You could try explicitly setting the full path to -Cdlltool in a RUSTFLAGS environment variable and seeing if that changes anything on earlier or new rust versions.

cc @mati865, if you have any ideas

[ChrisDenton]

Oh wait scratch that, I just had a thought. Does your TMP or TEMP environment variable not have spaces in the path? It could be that we were using the temporary directory rather than the build directory before and that works because of lack of spaces.

[mati865]

Yeah, sounds exactly like that: #150311
It should be sufficient to quote paths given to dlltool.

[ChrisDenton]

Hm, but it should already be quoted. We use the Command API which always adds quotes for arguments that contains spaces. We could use force_quotes but that only helps in the case where arguments wouldn't be quoted and they contain glob characters.