Fix npe xiantang (#247)

⭐️ close #246
* fix NPE for find process
* add test for no such process

go.mod

@@ -3,19 +3,16 @@ module github.com/cosmtrek/air
 go 1.17
 
 require (
-        github.com/fatih/color v1.10.0
-        github.com/fsnotify/fsnotify v1.4.9
-        github.com/imdario/mergo v0.3.12
-        github.com/pelletier/go-toml v1.8.1
-        golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e // indirect
+	github.com/fatih/color v1.10.0
+	github.com/fsnotify/fsnotify v1.4.9
+	github.com/imdario/mergo v0.3.12
+	github.com/pelletier/go-toml v1.8.1
+	golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e // indirect
 )
 
-require (
-        github.com/mitchellh/go-ps v1.0.0
-        github.com/pkg/errors v0.9.1
-)
+require github.com/pkg/errors v0.9.1
 
 require (
-        github.com/mattn/go-colorable v0.1.8 // indirect
-        github.com/mattn/go-isatty v0.0.12 // indirect
-)
+	github.com/mattn/go-colorable v0.1.8 // indirect
+	github.com/mattn/go-isatty v0.0.12 // indirect
+)

go.sum

@@ -10,8 +10,6 @@ github.com/mattn/go-colorable v0.1.8 h1:c1ghPdyEDarC70ftn0y+A/Ee++9zz8ljHG1b13eJ
 github.com/mattn/go-colorable v0.1.8/go.mod h1:u6P/XSegPjTcexA+o6vUJrdnUu04hMope9wVRipJSqc=
 github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHXY=
 github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
-github.com/mitchellh/go-ps v1.0.0 h1:i6ampVEEF4wQFF+bkYfwYgY+F/uYJDktmvLPf7qIgjc=
-github.com/mitchellh/go-ps v1.0.0/go.mod h1:J4lOc8z8yJs6vUwklHw2XEIiT4z4C40KtWVN3nvg8Pg=
 github.com/pelletier/go-toml v1.8.1 h1:1Nf83orprkJyknT6h7zbuEGUEjcyVlCxSUGTENmNCRM=
 github.com/pelletier/go-toml v1.8.1/go.mod h1:T2/BmBdy8dvIRq1a/8aqjN41wvWlN4lrapLU/GW4pbc=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
@@ -21,7 +19,6 @@ golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e h1:fLOSk5Q00efkSvAm+4xcoXD+RRmLmmulPn5I3Y9F2EM=
 golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

runner/util_darwin.go

@@ -7,7 +7,6 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/mitchellh/go-ps"
 	"github.com/pkg/errors"
 )
 
@@ -22,15 +21,18 @@ func (e *Engine) killCmd(cmd *exec.Cmd) (pid int, err error) {
 		}
 		time.Sleep(e.config.Build.KillDelay * time.Millisecond)
 	}
-
-	// find process by pid and kill it and its children by group id
-	proc, err := ps.FindProcess(pid)
+	pgid, err := syscall.Getpgid(cmd.Process.Pid)
+	if err != nil {
+		return pgid, errors.Wrapf(err, "failed to get pgid, pid %v", pid)
+	}
+	err = syscall.Kill(-pgid, syscall.SIGKILL)
 	if err != nil {
-		return pid, errors.Wrapf(err, "failed to find process %d", pid)
+		return pid, errors.Wrapf(err, "failed to kill process by pgid %v", pgid)
 	}
-	err = syscall.Kill(-proc.Pid(), syscall.SIGKILL)
+	// Wait releases any resources associated with the Process.
+	_, err = cmd.Process.Wait()
 	if err != nil {
-		return pid, errors.Wrapf(err, "failed to kill process %d", pid)
+		return pid, err
 	}
 
 	e.mainDebug("killed process pid %d successed", pid)

runner/util_test.go

@@ -1,13 +1,15 @@
 package runner
 
 import (
+	"errors"
 	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"
+	"syscall"
 	"testing"
 	"time"
 )
@@ -143,6 +145,27 @@ func TestAdaptToVariousPlatforms(t *testing.T) {
 	}
 }
 
+func Test_killCmd_no_process(t *testing.T) {
+	e := Engine{
+		config: &config{
+			Build: cfgBuild{
+				SendInterrupt: false,
+			},
+		},
+	}
+	_, err := e.killCmd(&exec.Cmd{
+		Process: &os.Process{
+			Pid: 9999,
+		},
+	})
+	if err == nil {
+		t.Errorf("expected error but got none")
+	}
+	if !errors.Is(err, syscall.ESRCH) {
+		t.Errorf("expected '%s' but got '%s'", syscall.ESRCH, errors.Unwrap(err))
+	}
+}
+
 func Test_killCmd_SendInterrupt_false(t *testing.T) {
 	_, b, _, _ := runtime.Caller(0)