fix handling of plus build lines

Signed-off-by: Achille Roussel <[email protected]>

compiler/comment.go

@@ -2,9 +2,6 @@ package compiler
 
 import (
 	"go/ast"
-	"go/build/constraint"
-	"slices"
-	"strings"
 )
 
 func appendCommentGroup(comments []*ast.Comment, group *ast.CommentGroup) []*ast.Comment {
@@ -33,26 +30,3 @@ func commentGroupsOf(file *ast.File) []*ast.CommentGroup {
 	}
 	return groups
 }
-
-const gobuild = "//go:build"
-
-func parseBuildTags(file *ast.File) (constraint.Expr, error) {
-	for _, group := range commentGroupsOf(file) {
-		for _, comment := range group.List {
-			if strings.HasPrefix(comment.Text, gobuild) {
-				return constraint.Parse(comment.Text)
-			}
-		}
-	}
-	return nil, nil
-}
-
-func stripBuildTagsOf(file *ast.File) {
-	for _, group := range commentGroupsOf(file) {
-		for i, comment := range group.List {
-			if strings.HasPrefix(comment.Text, gobuild) {
-				group.List = slices.Delete(group.List, i, i+1)
-			}
-		}
-	}
-}

compiler/compile.go

@@ -186,18 +186,12 @@ func (c *compiler) compile(path string) error {
 }
 
 func (c *compiler) writeFile(path string, file *ast.File, changeBuildTags func(constraint.Expr) constraint.Expr) error {
-	f, err := os.Create(path)
-	if err != nil {
-		return err
-	}
-	defer f.Close()
-
 	buildTags, err := parseBuildTags(file)
 	if err != nil {
 		return err
 	}
 	buildTags = changeBuildTags(buildTags)
-	stripBuildTagsOf(file)
+	stripBuildTagsOf(file, path)
 
 	// Comments are awkward to attach to the tree (they rely on token.Pos, which
 	// is coupled to a token.FileSet). Instead, just write out the raw strings.
@@ -207,6 +201,13 @@ func (c *compiler) writeFile(path string, file *ast.File, changeBuildTags func(c
 		b.WriteString(buildTags.String())
 		b.WriteString("\n\n")
 	}
+
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
 	if _, err := f.WriteString(b.String()); err != nil {
 		return err
 	}

compiler/constraint.go

@@ -1,8 +1,10 @@
 package compiler
 
 import (
+	"go/ast"
 	"go/build/constraint"
 	"reflect"
+	"slices"
 )
 
 func containsExpr(expr, contains constraint.Expr) bool {
@@ -36,3 +38,42 @@ func withoutBuildTag(expr constraint.Expr, buildTag *constraint.TagExpr) constra
 		return &constraint.AndExpr{X: expr, Y: notBuildTag}
 	}
 }
+
+func parseBuildTags(file *ast.File) (constraint.Expr, error) {
+	groups := commentGroupsOf(file)
+
+	for _, group := range groups {
+		for _, c := range group.List {
+			if constraint.IsGoBuild(c.Text) {
+				return constraint.Parse(c.Text)
+			}
+		}
+	}
+
+	var plusBuildLines constraint.Expr
+	for _, group := range groups {
+		for _, c := range group.List {
+			if constraint.IsPlusBuild(c.Text) {
+				x, err := constraint.Parse(c.Text)
+				if err != nil {
+					return nil, err
+				}
+				if plusBuildLines == nil {
+					plusBuildLines = x
+				} else {
+					plusBuildLines = &constraint.AndExpr{X: plusBuildLines, Y: x}
+				}
+			}
+		}
+	}
+
+	return plusBuildLines, nil
+}
+
+func stripBuildTagsOf(file *ast.File, path string) {
+	for _, group := range commentGroupsOf(file) {
+		group.List = slices.DeleteFunc(group.List, func(c *ast.Comment) bool {
+			return constraint.IsGoBuild(c.Text) || constraint.IsPlusBuild(c.Text)
+		})
+	}
+}

compiler/testdata/http/main.go

@@ -1,3 +1,5 @@
+//go:build !durable
+
 package main
 
 import (

compiler/testdata/http/main_generated.go

@@ -0,0 +1,106 @@
+//go:build durable
+
+package main
+
+import (
+	http "net/http"
+	coroutine "github.com/stealthrocket/coroutine"
+	fmt "fmt"
+)
+import _types "github.com/stealthrocket/coroutine/types"
+
+type yieldingRoundTripper struct {
+}
+//go:noinline
+func RoundTrip(req *http.Request) (_ *http.Response, _ error) {
+	_c := coroutine.LoadContext[*http.Request, *http.Response]()
+	_f, _fp := _c.Push()
+	var _f0 *struct {
+		X0 *http.Request
+		X1 *http.Response
+	}
+	if _f.IP == 0 {
+		_f0 = &struct {
+			X0 *http.Request
+			X1 *http.Response
+		}{X0: req}
+	} else {
+		_f0 = _f.Get(0).(*struct {
+			X0 *http.Request
+			X1 *http.Response
+		})
+	}
+	defer func() {
+		if _c.Unwinding() {
+			_f.Set(0, _f0)
+			_c.Store(_fp, _f)
+		} else {
+			_c.Pop()
+		}
+	}()
+	switch {
+	case _f.IP < 2:
+		_f0.X1 = coroutine.Yield[*http.Request, *http.Response](_f0.X0)
+		_f.IP = 2
+		fallthrough
+	case _f.IP < 3:
+		return _f0.X1, nil
+	}
+	return
+}
+//go:noinline
+func work() {
+	_c := coroutine.LoadContext[*http.Request, *http.Response]()
+	_f, _fp := _c.Push()
+	var _f0 *struct {
+		X0 *http.Response
+		X1 error
+	}
+	if _f.IP == 0 {
+		_f0 = &struct {
+			X0 *http.Response
+			X1 error
+		}{}
+	} else {
+		_f0 = _f.Get(0).(*struct {
+			X0 *http.Response
+			X1 error
+		})
+	}
+	defer func() {
+		if _c.Unwinding() {
+			_f.Set(0, _f0)
+			_c.Store(_fp, _f)
+		} else {
+			_c.Pop()
+		}
+	}()
+	switch {
+	case _f.IP < 2:
+		_f0.X0, _f0.X1 = http.Get("http://example.com")
+		_f.IP = 2
+		fallthrough
+	case _f.IP < 3:
+		if _f0.X1 != nil {
+			panic(_f0.X1)
+		}
+		_f.IP = 3
+		fallthrough
+	case _f.IP < 4:
+		fmt.Println(_f0.X0.StatusCode)
+	}
+}
+func main() {
+	http.DefaultTransport = &yieldingRoundTripper{}
+	c := coroutine.New[*http.Request, *http.Response](work)
+	for c.Next() {
+		req := c.Recv()
+		fmt.Println("Requesting", req.URL.String())
+		c.Send(&http.Response{StatusCode: 200})
+	}
+}
+func init() {
+	_types.RegisterFunc[func(req *http.Request) (_ *http.Response, _ error)]("github.com/stealthrocket/coroutine/compiler/testdata/http.RoundTrip")
+	_types.RegisterFunc[func()]("github.com/stealthrocket/coroutine/compiler/testdata/http.main")
+	_types.RegisterFunc[func()]("github.com/stealthrocket/coroutine/compiler/testdata/http.work")
+}