releases/compiler: Support setting build tags in compiler

.gitignore

@@ -15,5 +15,6 @@
 # vendor/
 
 # Ephemeral directories
+/.idea
 /bin
 /test-reports

releases/compiler/compiler.go

@@ -30,6 +30,7 @@ type Work struct {
 	Target       string
 	Source       string
 	WithCoverage bool
+	Tags         string
 	Environment  []string
 
 	Result *string
@@ -53,21 +54,32 @@ func (c *compiler) Compile(ctx context.Context, work Work) (string, error) {
 	goBin := goPath()
 	var cmd *exec.Cmd
 	if !work.WithCoverage {
-		// #nosec - this is fine
-		cmd = exec.CommandContext(ctx, goBin, "build",
-			"-ldflags="+c.ldFlags,
+		args := []string{
+			"build",
+			"-ldflags=" + c.ldFlags,
 			"-o", path,
-			work.Source,
-		)
-	} else {
+		}
+		if work.Tags != "" {
+			args = append(args, "-tags", work.Tags)
+		}
+		args = append(args, work.Source)
 		// #nosec - this is fine
-		cmd = exec.CommandContext(ctx, goBin, "test",
+		cmd = exec.CommandContext(ctx, goBin, args...)
+	} else {
+		args := []string{
+			"test",
 			"-coverpkg=./...",
 			"-c",
-			"-tags", "testrunmain",
 			work.Source,
 			"-o", path,
-		)
+			"-tags", "testrunmain",
+		}
+		if work.Tags != "" {
+			args[len(args)-1] += " " + work.Tags
+		}
+		args = append(args, work.Source)
+		// #nosec - this is fine
+		cmd = exec.CommandContext(ctx, goBin, args...)
 	}
 
 	cmd.Dir = cwd

releases/compiler/compiler_test.go

@@ -21,7 +21,7 @@ func TestCompiler_Compile(t *testing.T) {
 		binary, err = c.Compile(context.Background(), Work{
 			Name:        "name",
 			Target:      "../..",
-			Source:      "./testing/compiler/internal/cmd",
+			Source:      "./releases/compiler/internal/cmd",
 			Environment: []string{"FOO=foo", "BAR=bar"},
 		})
 		assert.Assert(t, err)

releases/compiler/internal/cmd2/main.go

@@ -6,5 +6,5 @@ import (
 )
 
 func main() {
-	fmt.Printf("command 2: %v\n", os.Args[1:])
+	fmt.Printf("command 2: %v %s\n", os.Args[1:], importantString())
 }

releases/compiler/internal/cmd2/with_tags.go

@@ -0,0 +1,8 @@
+//go:build work
+// +build work
+
+package main
+
+func importantString() string {
+	return "correct"
+}

releases/compiler/internal/cmd2/without_tags.go

@@ -0,0 +1,8 @@
+//go:build !work
+// +build !work
+
+package main
+
+func importantString() string {
+	return "wrong"
+}

releases/compiler/internal/cmd3/main.go

@@ -0,0 +1,10 @@
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func main() {
+	fmt.Printf("command 3: %v %s\n", os.Args[1:], importantString())
+}

releases/compiler/internal/cmd3/main_test.go

@@ -0,0 +1,23 @@
+//go:build testrunmain
+// +build testrunmain
+
+package main
+
+import (
+	"os"
+	"testing"
+)
+
+func TestRunMain(t *testing.T) {
+	stripTestArgs()
+	main()
+}
+
+func stripTestArgs() {
+	for i, arg := range os.Args {
+		if arg == "--" {
+			os.Args = append([]string{os.Args[0]}, os.Args[i+1:]...)
+			break
+		}
+	}
+}

releases/compiler/internal/cmd3/with_tags.go

@@ -0,0 +1,8 @@
+//go:build work
+// +build work
+
+package main
+
+func importantString() string {
+	return "correct"
+}

releases/compiler/internal/cmd3/without_tags.go

@@ -0,0 +1,8 @@
+//go:build !work
+// +build !work
+
+package main
+
+func importantString() string {
+	return "wrong"
+}

releases/compiler/parallel_test.go

@@ -1,13 +1,15 @@
 package compiler
 
 import (
-	"context"
 	"os"
 	"testing"
 
 	"gotest.tools/v3/assert"
 	"gotest.tools/v3/fs"
+	"gotest.tools/v3/golden"
 	"gotest.tools/v3/icmd"
+
+	"github.com/circleci/ex/testing/testcontext"
 )
 
 func TestParallel_Compile(t *testing.T) {
@@ -18,7 +20,7 @@ func TestParallel_Compile(t *testing.T) {
 		Parallelism: 2,
 	})
 
-	var binary1, binary2 string
+	var binary1, binary2, binary3 string
 	t.Cleanup(func() {
 		c.Cleanup()
 	})
@@ -28,23 +30,38 @@ func TestParallel_Compile(t *testing.T) {
 			Result:      &binary1,
 			Name:        "binary1",
 			Target:      "../..",
-			Source:      "./testing/compiler/internal/cmd",
+			Source:      "./releases/compiler/internal/cmd",
 			Environment: []string{"FOO=foo1", "BAR=bar1"},
 		})
 		c.Add(Work{
 			Result:      &binary2,
 			Name:        "binary2",
 			Target:      "../..",
-			Source:      "./testing/compiler/internal/cmd2",
+			Source:      "./releases/compiler/internal/cmd2",
 			Environment: []string{"FOO=foo2", "BAR=bar2"},
+			Tags:        "work",
+		})
+		c.Add(Work{
+			Result:       &binary3,
+			Name:         "binary3",
+			Target:       "../..",
+			Source:       "./releases/compiler/internal/cmd3",
+			Environment:  []string{"FOO=foo2", "BAR=bar2"},
+			Tags:         "work",
+			WithCoverage: true,
 		})
 
-		err := c.Run(context.Background())
+		err := c.Run(testcontext.Background())
 		assert.Check(t, err)
+
 		_, err = os.Stat(binary1)
 		assert.Check(t, err)
+
 		_, err = os.Stat(binary2)
 		assert.Check(t, err)
+
+		_, err = os.Stat(binary3)
+		assert.Check(t, err)
 	}))
 
 	t.Run("Run binaries", func(t *testing.T) {
@@ -55,7 +72,21 @@ func TestParallel_Compile(t *testing.T) {
 
 		res = icmd.RunCommand(binary2, "arg1", "arg2", "arg3")
 		assert.Check(t, res.Equal(icmd.Expected{
-			Out: "command 2: [arg1 arg2 arg3]",
+			Out: "command 2: [arg1 arg2 arg3] correct",
+		}))
+	})
+
+	t.Run("Run binary with coverage", func(t *testing.T) {
+		// N.B. we use the txt extension here to not fall foul of the .out in .gitignore
+		// we would expect instrumented binary runs to use .o or .out for coverage report extensions.
+		file := fs.NewFile(t, "coverage.txt")
+		res := icmd.RunCommand(binary3, "-test.run", "^TestRunMain$",
+			"-test.coverprofile", file.Path(),
+			"--",
+			"arg1", "arg2", "arg3")
+		assert.Check(t, res.Equal(icmd.Expected{
+			Out: "command 3: [arg1 arg2 arg3] correct",
 		}))
+		assert.Check(t, golden.String(string(golden.Get(t, file.Path())), "coverage.txt"))
 	})
 }

releases/compiler/testdata/coverage.txt

@@ -1,2 +1,3 @@
 mode: set
-github.com/circleci/ex/testing/compiler/internal/cmd/main.go:8.13,10.2 1 1
+github.com/circleci/ex/releases/compiler/internal/cmd3/main.go:8.13,10.2 1 1
+github.com/circleci/ex/releases/compiler/internal/cmd3/with_tags.go:6.31,8.2 1 1