Filter target build-tags if user specified an overriding option (tiny…

…go-org#3357)

compileopts: Filter target build-tags if user specified an overriding option

compileopts/config.go

@@ -75,7 +75,8 @@ func (c *Config) GOARM() string {
 
 // BuildTags returns the complete list of build tags used during this build.
 func (c *Config) BuildTags() []string {
-	tags := append(c.Target.BuildTags, []string{"tinygo", "math_big_pure_go", "gc." + c.GC(), "scheduler." + c.Scheduler(), "serial." + c.Serial()}...)
+	targetTags := filterTags(c.Target.BuildTags, c.Options.Tags)
+	tags := append(targetTags, []string{"tinygo", "math_big_pure_go", "gc." + c.GC(), "scheduler." + c.Scheduler(), "serial." + c.Serial()}...)
 	for i := 1; i <= c.GoMinorVersion; i++ {
 		tags = append(tags, fmt.Sprintf("go1.%d", i))
 	}
@@ -550,3 +551,27 @@ type TestConfig struct {
 	CompileTestBinary bool
 	// TODO: Filter the test functions to run, include verbose flag, etc
 }
+
+// filterTags removes predefined build tags for a target if a conflicting option
+// is provided by the user.
+func filterTags(targetTags []string, userTags []string) []string {
+	var filtered []string
+	for _, t := range targetTags {
+		switch {
+		case strings.HasPrefix(t, "runtime_memhash_"):
+			overridden := false
+			for _, ut := range userTags {
+				if strings.HasPrefix(ut, "runtime_memhash_") {
+					overridden = true
+					break
+				}
+			}
+			if !overridden {
+				filtered = append(filtered, t)
+			}
+		default:
+			filtered = append(filtered, t)
+		}
+	}
+	return filtered
+}

compileopts/config_test.go

@@ -0,0 +1,132 @@
+package compileopts
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+)
+
+func TestBuildTags(t *testing.T) {
+	tests := []struct {
+		targetTags []string
+		userTags   []string
+		result     []string
+	}{
+		{
+			targetTags: []string{},
+			userTags:   []string{},
+			result: []string{
+				"tinygo",
+				"math_big_pure_go",
+				"gc.conservative",
+				"scheduler.none",
+				"serial.none",
+			},
+		},
+		{
+			targetTags: []string{"bear"},
+			userTags:   []string{},
+			result: []string{
+				"bear",
+				"tinygo",
+				"math_big_pure_go",
+				"gc.conservative",
+				"scheduler.none",
+				"serial.none",
+			},
+		},
+		{
+			targetTags: []string{},
+			userTags:   []string{"cat"},
+			result: []string{
+				"tinygo",
+				"math_big_pure_go",
+				"gc.conservative",
+				"scheduler.none",
+				"serial.none",
+				"cat",
+			},
+		},
+		{
+			targetTags: []string{"bear"},
+			userTags:   []string{"cat"},
+			result: []string{
+				"bear",
+				"tinygo",
+				"math_big_pure_go",
+				"gc.conservative",
+				"scheduler.none",
+				"serial.none",
+				"cat",
+			},
+		},
+		{
+			targetTags: []string{"bear", "runtime_memhash_leveldb"},
+			userTags:   []string{"cat"},
+			result: []string{
+				"bear",
+				"runtime_memhash_leveldb",
+				"tinygo",
+				"math_big_pure_go",
+				"gc.conservative",
+				"scheduler.none",
+				"serial.none",
+				"cat",
+			},
+		},
+		{
+			targetTags: []string{"bear", "runtime_memhash_leveldb"},
+			userTags:   []string{"cat", "runtime_memhash_leveldb"},
+			result: []string{
+				"bear",
+				"tinygo",
+				"math_big_pure_go",
+				"gc.conservative",
+				"scheduler.none",
+				"serial.none",
+				"cat",
+				"runtime_memhash_leveldb",
+			},
+		},
+		{
+			targetTags: []string{"bear", "runtime_memhash_leveldb"},
+			userTags:   []string{"cat", "runtime_memhash_sip"},
+			result: []string{
+				"bear",
+				"tinygo",
+				"math_big_pure_go",
+				"gc.conservative",
+				"scheduler.none",
+				"serial.none",
+				"cat",
+				"runtime_memhash_sip",
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		tt := tc
+		t.Run(fmt.Sprintf("%s+%s", strings.Join(tt.targetTags, ","), strings.Join(tt.userTags, ",")), func(t *testing.T) {
+			c := &Config{
+				Target: &TargetSpec{
+					BuildTags: tt.targetTags,
+				},
+				Options: &Options{
+					Tags: tt.userTags,
+				},
+			}
+
+			res := c.BuildTags()
+
+			if len(res) != len(tt.result) {
+				t.Errorf("expected %d tags, got %d", len(tt.result), len(res))
+			}
+
+			for i, tag := range tt.result {
+				if tag != res[i] {
+					t.Errorf("tag %d: expected %s, got %s", i, tt.result[i], tag)
+				}
+			}
+		})
+	}
+}