From 17eae5b0d369b5a421cf716cf969f6810b696fd4 Mon Sep 17 00:00:00 2001
From: David Anderson <danderson@tailscale.com>
Date: Fri, 19 Jan 2024 18:09:42 -0800
Subject: [PATCH] tool/gocross: force use of our custom toolchain

The new 'toolchain' directive in go.mod can sometimes force
the use of an upstream toolchain against our wishes. Concurrently,
some of our dependencies have added the 'toolchain' directive, which
transitively adds it to our own go.mod. Force all uses of gocross to
ignore that directive and stick to our customized toolchain.

Updates #cleanup

Signed-off-by: David Anderson <danderson@tailscale.com>
---
 tool/gocross/autoflags.go      |  1 +
 tool/gocross/autoflags_test.go | 44 ++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/tool/gocross/autoflags.go b/tool/gocross/autoflags.go
index 7d133de01..825f86965 100644
--- a/tool/gocross/autoflags.go
+++ b/tool/gocross/autoflags.go
@@ -191,6 +191,7 @@ func autoflagsForTest(argv []string, env *Environment, goroot, nativeGOOS, nativ
 	env.Set("CC", cc)
 	env.Set("TS_LINK_FAIL_REFLECT", boolStr(failReflect))
 	env.Set("GOROOT", goroot)
+	env.Set("GOTOOLCHAIN", "local")
 
 	if subcommand == "env" {
 		return argv, env, nil
diff --git a/tool/gocross/autoflags_test.go b/tool/gocross/autoflags_test.go
index e5202efc9..66072f420 100644
--- a/tool/gocross/autoflags_test.go
+++ b/tool/gocross/autoflags_test.go
@@ -49,6 +49,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=linux (was <nil>)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "build",
@@ -74,6 +75,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=linux (was <nil>)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "install",
@@ -102,6 +104,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=linux (was <nil>)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "build",
@@ -130,6 +133,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=freebsd (was freebsd)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "build",
@@ -155,6 +159,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=linux (was <nil>)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "test",
@@ -184,6 +189,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=windows (was windows)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "build",
@@ -209,6 +215,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=darwin (was <nil>)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "build",
@@ -237,6 +244,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=darwin (was <nil>)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "build",
@@ -265,6 +273,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=ios (was ios)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=1 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "build",
@@ -297,6 +306,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=darwin (was darwin)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "build",
@@ -329,6 +339,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=ios (was ios)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=1 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "build",
@@ -354,6 +365,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=linux (was <nil>)
 GOROOT=/special/toolchain/path (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"go", "build",
@@ -379,6 +391,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=linux (was <nil>)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "list",
@@ -407,6 +420,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=linux (was <nil>)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"gocross", "build",
@@ -433,6 +447,7 @@ GOARM=5 (was <nil>)
 GOMIPS=softfloat (was <nil>)
 GOOS=linux (was <nil>)
 GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was <nil>)
 TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 			wantArgv: []string{
 				"go", "run",
@@ -443,6 +458,35 @@ TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
 				"--tags=foo",
 			},
 		},
+		{
+			name: "linux_amd64_to_linux_amd64_custom_toolchain",
+			env: map[string]string{
+				"GOTOOLCHAIN": "go1.30rc5",
+			},
+			argv:         []string{"gocross", "build", "./cmd/tailcontrol"},
+			goroot:       "/goroot",
+			nativeGOOS:   "linux",
+			nativeGOARCH: "amd64",
+
+			envDiff: `CC=cc (was <nil>)
+CGO_CFLAGS=-O3 -std=gnu11 (was <nil>)
+CGO_ENABLED=1 (was <nil>)
+CGO_LDFLAGS= (was <nil>)
+GOARCH=amd64 (was <nil>)
+GOARM=5 (was <nil>)
+GOMIPS=softfloat (was <nil>)
+GOOS=linux (was <nil>)
+GOROOT=/goroot (was <nil>)
+GOTOOLCHAIN=local (was go1.30rc5)
+TS_LINK_FAIL_REFLECT=0 (was <nil>)`,
+			wantArgv: []string{
+				"gocross", "build",
+				"-trimpath",
+				"-tags=tailscale_go,osusergo,netgo",
+				"-ldflags", "-X tailscale.com/version.longStamp=1.2.3-long -X tailscale.com/version.shortStamp=1.2.3 -X tailscale.com/version.gitCommitStamp=abcd -X tailscale.com/version.extraGitCommitStamp=defg '-extldflags=-static'",
+				"./cmd/tailcontrol",
+			},
+		},
 	}
 
 	for _, test := range tests {