From 07466fefe641ba728bacc0c674f8cd73db2eb4a5 Mon Sep 17 00:00:00 2001
From: visualfc <visualfc@gmail.com>
Date: Wed, 8 Jun 2022 21:57:45 +0800
Subject: [PATCH 1/3] gopmod: lookupExternPkg error

---
 gopmod/module.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gopmod/module.go b/gopmod/module.go
index 58e430e..28e2fd0 100644
--- a/gopmod/module.go
+++ b/gopmod/module.go
@@ -17,6 +17,7 @@
 package gopmod
 
 import (
+	"fmt"
 	"log"
 	"path/filepath"
 	"runtime"
@@ -130,7 +131,8 @@ func (p *Module) lookupExternPkg(pkgPath string) (pkg *Package, err error) {
 			return
 		}
 	}
-	err = syscall.ENOENT
+	err = fmt.Errorf(`no required module provides package %v; to add it:
+	go get %v`, pkgPath, pkgPath)
 	return
 }
 

From d3dfb6952ce28511edf634214a87c06b4391015b Mon Sep 17 00:00:00 2001
From: visualfc <visualfc@gmail.com>
Date: Thu, 9 Jun 2022 14:17:24 +0800
Subject: [PATCH 2/3] mod: MissingPkgError

---
 gopmod/module.go |  4 +---
 mod.go           | 10 ++++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/gopmod/module.go b/gopmod/module.go
index 28e2fd0..9a5e46f 100644
--- a/gopmod/module.go
+++ b/gopmod/module.go
@@ -17,7 +17,6 @@
 package gopmod
 
 import (
-	"fmt"
 	"log"
 	"path/filepath"
 	"runtime"
@@ -131,8 +130,7 @@ func (p *Module) lookupExternPkg(pkgPath string) (pkg *Package, err error) {
 			return
 		}
 	}
-	err = fmt.Errorf(`no required module provides package %v; to add it:
-	go get %v`, pkgPath, pkgPath)
+	err = &mod.MissingPkgError{Path: pkgPath}
 	return
 }
 
diff --git a/mod.go b/mod.go
index 17ff88e..cb0225c 100644
--- a/mod.go
+++ b/mod.go
@@ -17,6 +17,7 @@
 package mod
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -68,4 +69,13 @@ func GOMOD(dir string) (file string, err error) {
 	return GOPMOD(dir, GoModOnly)
 }
 
+type MissingPkgError struct {
+	Path string
+}
+
+func (e *MissingPkgError) Error() string {
+	return fmt.Sprintf(`no required module provides package %v; to add it:
+	go get %v`, e.Path, e.Path)
+}
+
 // -----------------------------------------------------------------------------

From d3d5d45ee1c381005fc93a9d51583eec54637dec Mon Sep 17 00:00:00 2001
From: visualfc <visualfc@gmail.com>
Date: Fri, 10 Jun 2022 07:34:31 +0800
Subject: [PATCH 3/3] mod.MissingPkgError => gopmod.MissingError

---
 gopmod/module.go | 12 +++++++++++-
 mod.go           | 10 ----------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/gopmod/module.go b/gopmod/module.go
index 9a5e46f..1fe3007 100644
--- a/gopmod/module.go
+++ b/gopmod/module.go
@@ -17,6 +17,7 @@
 package gopmod
 
 import (
+	"fmt"
 	"log"
 	"path/filepath"
 	"runtime"
@@ -130,7 +131,7 @@ func (p *Module) lookupExternPkg(pkgPath string) (pkg *Package, err error) {
 			return
 		}
 	}
-	err = &mod.MissingPkgError{Path: pkgPath}
+	err = &MissingError{Path: pkgPath}
 	return
 }
 
@@ -210,4 +211,13 @@ func loadModFrom(mod module.Version, mode mod.Mode) (p *Module, err error) {
 	return Load(dir, mode)
 }
 
+type MissingError struct {
+	Path string
+}
+
+func (e *MissingError) Error() string {
+	return fmt.Sprintf(`no required module provides package %v; to add it:
+	gop get %v`, e.Path, e.Path)
+}
+
 // -----------------------------------------------------------------------------
diff --git a/mod.go b/mod.go
index cb0225c..17ff88e 100644
--- a/mod.go
+++ b/mod.go
@@ -17,7 +17,6 @@
 package mod
 
 import (
-	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -69,13 +68,4 @@ func GOMOD(dir string) (file string, err error) {
 	return GOPMOD(dir, GoModOnly)
 }
 
-type MissingPkgError struct {
-	Path string
-}
-
-func (e *MissingPkgError) Error() string {
-	return fmt.Sprintf(`no required module provides package %v; to add it:
-	go get %v`, e.Path, e.Path)
-}
-
 // -----------------------------------------------------------------------------