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Fix Windows MSVC build failure during ABI generation#388

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Fix Windows MSVC build failure during ABI generation#388
Copilot wants to merge 5 commits intomainfrom
copilot/fix-windows-build-failure

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Copilot AI commented Jan 14, 2026 •
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cargo near build fails on Windows with 55 unresolved external symbol linker errors (LNK2019) during ABI generation. The build succeeds with --no-abi.

Root Cause

ABI generation compiles the contract as a native dylib with near-sdk/__abi-generate. The near-sys crate declares NEAR runtime functions (read_register, register_len, etc.) as extern "C" - these are provided by the NEAR VM in wasm builds but don't exist in native builds. MSVC's linker rejects unresolved symbols by default, unlike Linux/macOS dynamic linkers.

Changes

  • Add Windows linker flag: Pass /FORCE:UNRESOLVED to MSVC linker when building ABI dylib, allowing unresolved symbols (safe since the dylib is only loaded for symbol extraction, never executed)

  • Fix RUSTFLAGS handling: Refactor cargo_native::compile::run to append -Awarnings to existing RUSTFLAGS instead of replacing them, ensuring Windows linker flag is preserved

// cargo-near-build/src/near/abi/generate/mod.rs
#[cfg(windows)]
{
    compile_env.push((env_keys::RUSTFLAGS, "-C link-arg=/FORCE:UNRESOLVED"));
}

The dylib is temporary and only used for ABI extraction via libloading - unresolved symbols never cause runtime issues.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

  • s3-us-west-1.amazonaws.com
    • Triggering command: /home/REDACTED/work/cargo-near/cargo-near/target/debug/build/near-workspaces-a8b4a713a403149e/build-script-build /home/REDACTED/work/cargo-near/cargo-near/target/debug/build/near-workspaces-a8b4a713a403149e/build-script-build --gdwarf-4 --64 --noexecstack -o crypto/x509/libcrypto-lib-v3_bitst.o /tmp/cccbl4ru.s /usr/sbin/cc AES_ASM -DECP_NIas /home/REDACTED/wor-I (dns block)
    • Triggering command: /home/REDACTED/work/cargo-near/.codeql-scratch/dbs/rust/working/target/debug/build/near-workspaces-2094825312d8cd28/build-script-build /home/REDACTED/work/cargo-near/.codeql-scratch/dbs/rust/working/target/debug/build/near-workspaces-2094825312d8cd28/build-script-build - -o /rust/working/ta-I N /rust/working/ta--gdwarf-4 .o cal/bin/cc 6e14519a1242e/oucc -gdwarf-4 -fno-omit-frame--c /rust/working/ta-o -O0 rget/debug/build-x rget/debug/buildassembler rget/debug/build/dev/null rget/debug/build/home/REDACTED/.rustup/toolchains/stable-x86_64-REDACTED-linux-gnu/bin/rustc rget/debug/build--crate-name pointer as (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

Original prompt

This section details on the original issue you should resolve

<issue_title>Windows (without WSL) build failure on ABI generation step</issue_title>
<issue_description>after installing binary release from latest https://github.com/near/cargo-near/releases/tag/cargo-near-v0.6.4 tag
with

irm https://github.com/near/cargo-near/releases/latest/download/cargo-near-installer.ps1 | iex

onto
image
image

a cargo near build command fails for a default project, generated by cargo near new:
image
image
image

A standalone cargo build --features near-sdk/__abi-generate command fails with similar error (with and without --release).

A cargo near build --no-abi succeeds:
image
As well as standalone cargo build --target wasm32-unknown-unknown (with and without --release).

</issue_description>

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Copilot AI and others added 4 commits January 14, 2026 01:11
@r-near
Add Windows MSVC linker flag for ABI generation
ca79069 
Co-authored-by: r-near <163825889+r-near@users.noreply.github.com>
@r-near
Fix RUSTFLAGS handling to append instead of replace
853e409 
Co-authored-by: r-near <163825889+r-near@users.noreply.github.com>
@r-near
Apply code formatting
3a431df 
Co-authored-by: r-near <163825889+r-near@users.noreply.github.com>
@r-near
Refactor RUSTFLAGS handling to avoid memory leak
78011cc 
Co-authored-by: r-near <163825889+r-near@users.noreply.github.com>
Copilot AI changed the title [WIP] Fix Windows build failure during ABI generation Fix Windows MSVC build failure during ABI generation Jan 14, 2026
Copilot AI requested a review from r-near January 14, 2026 01:25
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Windows (without WSL) build failure on ABI generation step

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