Build fails on Go 1.27.0: relocation target golang.org/x/net/http2.(*Transport).connPool not defined

Operating system

Linux

System version

Artix Linux (Targeting OpenWrt linux/arm64)

Installation type

Original sing-box Command Line

If you are using a graphical client, please provide the version of the client.

No response

Version

v1.14.0-rc.1 (commit: 8dd67a1e49711ce8a9a884bef60a2139ef36446f)

Description

I ran into a build error when trying to cross-compile the v1.14.0-rc.1 tag using the newly released Go 1.27.0. The build completely fails at the linker stage with an error complaining about a missing relocation target for connPool in http2.(*Transport).

It looks like Go 1.27 (or a bumped golang.org/x/net dependency) changed the internal connPool struct or unexported it in a way that breaks the go:linkname hack used in v2rayhttp.ResetTransport.

Downgrading my environment to the latest Go 1.26 release (1.26.7) fixes the issue immediately, and the binary compiles without a hitch using the exact same build flags.

Reproduction

1. Ensure Go 1.27.0 is installed.
2. Clone the repo and check out the release candidate:
3. git clone --branch v1.14.0-rc.1 --depth 1 https://github.com/SagerNet/sing-box.git
4. cd sing-box
5. GOOS=linux GOARCH=arm64 go build -v -trimpath -tags "with_utls,badlinkname,tfogo_checklinkname0" -ldflags "-checklinkname=0 -s -w" -o sing-box ./cmd/sing-box

Logs

# github.com/sagernet/sing-box/cmd/sing-box
github.com/sagernet/sing-box/transport/v2rayhttp.ResetTransport: relocation target golang.org/x/net/http2.(*Transport).connPool not defined

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Integrity requirements

• I confirm that I have read the documentation, understand the meaning of all the configuration items I wrote, and did not pile up seemingly useful options or default values.
• I confirm that I have provided the server and client configuration files and process that can be reproduced locally, instead of a complicated client configuration file that has been stripped of sensitive data.
• I confirm that I have provided the simplest configuration that can be used to reproduce the error I reported, instead of depending on remote servers, TUN, graphical interface clients, or other closed-source software.
• I confirm that I have provided the complete configuration files and logs, rather than just providing parts I think are useful out of confidence in my own intelligence.

Start by checking the v2rayhttp.ResetTransport entry point and reproduce the failure with the listed GOOS=linux GOARCH=arm64 go build command using Go 1.27.0. Trace how the go:linkname reference to golang.org/x/net/http2.(*Transport).connPool is used; done means the v1.14.0-rc.1 build completes successfully on Go 1.27.0 while retaining the reported Go 1.26 behavior.