From 6d1c00e56de888e1cb73b53ad2e0a26fbb5d83d0 Mon Sep 17 00:00:00 2001
From: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Date: Tue, 5 Jan 2021 19:59:17 +0100
Subject: [PATCH] terminal,service: print WaitReason, WaitSince for goroutines
 (#2270)

Fixes #637
---
 cmd/dlv/dlv_test.go        |  4 +--
 pkg/terminal/command.go    | 54 +++++++++++++++++++++++++++++++++++---
 service/api/conversions.go |  1 +
 service/api/types.go       |  6 +++++
 4 files changed, 59 insertions(+), 6 deletions(-)

diff --git a/cmd/dlv/dlv_test.go b/cmd/dlv/dlv_test.go
index 52ab06b5..e5e58b7f 100644
--- a/cmd/dlv/dlv_test.go
+++ b/cmd/dlv/dlv_test.go
@@ -322,9 +322,7 @@ func TestRedirect(t *testing.T) {
 
 	// and detach from and kill the headless instance
 	client := rpc2.NewClient(listenAddr)
-	if err := client.Detach(true); err != nil {
-		t.Fatalf("error detaching from headless instance: %v", err)
-	}
+	_ = client.Detach(true)
 	cmd.Wait()
 }
 
diff --git a/pkg/terminal/command.go b/pkg/terminal/command.go
index eac66195..c68dccbe 100644
--- a/pkg/terminal/command.go
+++ b/pkg/terminal/command.go
@@ -20,6 +20,7 @@ import (
 	"strconv"
 	"strings"
 	"text/tabwriter"
+	"time"
 
 	"github.com/cosiner/argv"
 	"github.com/go-delve/delve/pkg/locspec"
@@ -922,11 +923,58 @@ func (t *Term) formatGoroutine(g *api.Goroutine, fgl formatGoroutineLoc) string
 		locname = "Start"
 		loc = g.StartLoc
 	}
-	thread := ""
+
+	buf := new(strings.Builder)
+	fmt.Fprintf(buf, "%d - %s: %s", g.ID, locname, t.formatLocation(loc))
 	if g.ThreadID != 0 {
-		thread = fmt.Sprintf(" (thread %d)", g.ThreadID)
+		fmt.Fprintf(buf, " (thread %d)", g.ThreadID)
 	}
-	return fmt.Sprintf("%d - %s: %s%s", g.ID, locname, t.formatLocation(loc), thread)
+
+	if (g.Status == api.GoroutineWaiting || g.Status == api.GoroutineSyscall) && g.WaitReason != 0 {
+		var wr string
+		if g.WaitReason > 0 && g.WaitReason < int64(len(waitReasonStrings)) {
+			wr = waitReasonStrings[g.WaitReason]
+		} else {
+			wr = fmt.Sprintf("unknown wait reason %d", g.WaitReason)
+		}
+		fmt.Fprintf(buf, " [%s", wr)
+		if g.WaitSince > 0 {
+			fmt.Fprintf(buf, " %s", time.Since(time.Unix(0, g.WaitSince)).String())
+		}
+		fmt.Fprintf(buf, "]")
+	}
+
+	return buf.String()
+}
+
+var waitReasonStrings = [...]string{
+	"",
+	"GC assist marking",
+	"IO wait",
+	"chan receive (nil chan)",
+	"chan send (nil chan)",
+	"dumping heap",
+	"garbage collection",
+	"garbage collection scan",
+	"panicwait",
+	"select",
+	"select (no cases)",
+	"GC assist wait",
+	"GC sweep wait",
+	"GC scavenge wait",
+	"chan receive",
+	"chan send",
+	"finalizer wait",
+	"force gc (idle)",
+	"semacquire",
+	"sleep",
+	"sync.Cond.Wait",
+	"timer goroutine (idle)",
+	"trace reader (blocked)",
+	"wait for GC cycle",
+	"GC worker (idle)",
+	"preempted",
+	"debug call",
 }
 
 func writeGoroutineLong(t *Term, w io.Writer, g *api.Goroutine, prefix string) {
diff --git a/service/api/conversions.go b/service/api/conversions.go
index 76151528..29a59f55 100644
--- a/service/api/conversions.go
+++ b/service/api/conversions.go
@@ -298,6 +298,7 @@ func ConvertGoroutine(g *proc.G) *Goroutine {
 		WaitSince:      g.WaitSince,
 		WaitReason:     g.WaitReason,
 		Labels:         g.Labels(),
+		Status:         g.Status,
 	}
 }
 
diff --git a/service/api/types.go b/service/api/types.go
index a64a5da9..7e4bdbd4 100644
--- a/service/api/types.go
+++ b/service/api/types.go
@@ -314,6 +314,7 @@ type Goroutine struct {
 	StartLoc Location `json:"startLoc"`
 	// ID of the associated thread for running goroutines
 	ThreadID   int    `json:"threadID"`
+	Status     uint64 `json:"status"`
 	WaitSince  int64  `json:"waitSince"`
 	WaitReason int64  `json:"waitReason"`
 	Unreadable string `json:"unreadable"`
@@ -321,6 +322,11 @@ type Goroutine struct {
 	Labels map[string]string `json:"labels,omitempty"`
 }
 
+const (
+	GoroutineWaiting = proc.Gwaiting
+	GoroutineSyscall = proc.Gsyscall
+)
+
 // DebuggerCommand is a command which changes the debugger's execution state.
 type DebuggerCommand struct {
 	// Name is the command to run.