pkg/eval: Move intCh from Evaler to Frame.

This avoids a race condition when using EvalInTTY concurrently.

This addresses #73.

pkg/eval/builtin_special.go

@@ -307,7 +307,7 @@ func evalModule(fm *Frame, key string, src *Source) (Ns, error) {
 		fm.Evaler, src,
 		diag.Ranging{From: 0, To: len(src.Code)},
 		modGlobal, make(Ns),
-		fm.ports,
+		fm.intCh, fm.ports,
 		fm.addTraceback(), false,
 	}
 

pkg/eval/eval.go

@@ -47,9 +47,6 @@ type Evaler struct {
 	beforeChdir []func(string)
 	afterChdir  []func(string)
 
-	// Used to receive SIGINT.
-	intCh chan struct{}
-
 	// State of the module system.
 	libDir  string
 	bundled map[string]string
@@ -142,7 +139,6 @@ func NewEvaler() *Evaler {
 		},
 		bundled: bundled.Get(),
 		Editor:  nil,
-		intCh:   nil,
 	}
 
 	beforeChdirElvish, afterChdirElvish := vector.Empty, vector.Empty
@@ -282,10 +278,8 @@ func (ev *Evaler) EvalInTTY(op Op) error {
 	defer stdPorts.close()
 
 	intCh, cleanupInt := listenInterrupts()
-	ev.intCh = intCh
 	defer func() {
 		cleanupInt()
-		ev.intCh = nil
 		// Put myself in foreground, in case some command has put me in background.
 		err := putSelfInFg()
 		if err != nil {
@@ -293,7 +287,9 @@ func (ev *Evaler) EvalInTTY(op Op) error {
 		}
 	}()
 
-	return ev.Eval(op, stdPorts.ports[:])
+	ec := NewTopFrame(ev, op.Src, stdPorts.ports[:])
+	ec.intCh = intCh
+	return ec.eval(op.Inner)
 }
 
 // Compile compiles Elvish code in the global scope. If the error is not nil, it

pkg/eval/frame.go

@@ -16,11 +16,14 @@ import (
 // shortly after creation; new Frame's are "forked" when needed.
 type Frame struct {
 	*Evaler
+
 	srcMeta  *Source
 	srcRange diag.Ranging
 
 	local, up Ns
-	ports     []*Port
+
+	intCh chan struct{}
+	ports []*Port
 
 	traceback *stackTrace
 
@@ -35,7 +38,7 @@ func NewTopFrame(ev *Evaler, src *Source, ports []*Port) *Frame {
 		ev, src,
 		diag.Ranging{From: 0, To: len(src.Code)},
 		ev.Global, make(Ns),
-		ports,
+		nil, ports,
 		nil, false,
 	}
 }
@@ -128,7 +131,7 @@ func (fm *Frame) fork(name string) *Frame {
 	return &Frame{
 		fm.Evaler, fm.srcMeta, fm.srcRange,
 		fm.local, fm.up,
-		newPorts,
+		fm.intCh, newPorts,
 		fm.traceback, fm.background,
 	}
 }