Remove vendored path prefix of vendored packages

ql/src/semmle/go/Packages.qll

@@ -12,7 +12,11 @@ class Package extends @package {
   string getName() { packages(this, result, _, _) }
 
   /** Gets the path of this package. */
-  string getPath() { packages(this, _, result, _) }
+  string getPath() {
+    exists(string fullPath | packages(this, _, fullPath, _) |
+      result = fullPath.regexpReplaceAll("^.*/vendor/", "")
+    )
+  }
 
   /** Gets the scope of this package. */
   PackageScope getScope() { packages(this, _, _, result) }

ql/test/library-tests/semmle/go/Packages/PackagePath.expected

@@ -0,0 +1,31 @@
+| package errors | errors |
+| package fmt | fmt |
+| package github.com/github/codeql-go/ql/test/library-tests/semmle/go/main | github.com/github/codeql-go/ql/test/library-tests/semmle/go/main |
+| package github.com/nonexistent-test-pkg | github.com/nonexistent-test-pkg |
+| package internal/bytealg | internal/bytealg |
+| package internal/cpu | internal/cpu |
+| package internal/fmtsort | internal/fmtsort |
+| package internal/oserror | internal/oserror |
+| package internal/poll | internal/poll |
+| package internal/race | internal/race |
+| package internal/reflectlite | internal/reflectlite |
+| package internal/syscall/unix | internal/syscall/unix |
+| package internal/testlog | internal/testlog |
+| package io | io |
+| package math | math |
+| package math/bits | math/bits |
+| package os | os |
+| package reflect | reflect |
+| package runtime | runtime |
+| package runtime/internal/atomic | runtime/internal/atomic |
+| package runtime/internal/math | runtime/internal/math |
+| package runtime/internal/sys | runtime/internal/sys |
+| package sort | sort |
+| package strconv | strconv |
+| package sync | sync |
+| package sync/atomic | sync/atomic |
+| package syscall | syscall |
+| package time | time |
+| package unicode | unicode |
+| package unicode/utf8 | unicode/utf8 |
+| package unsafe | unsafe |

ql/test/library-tests/semmle/go/Packages/PackagePath.ql

@@ -0,0 +1,4 @@
+import go
+
+from Package pkg
+select pkg, pkg.getPath()

ql/test/library-tests/semmle/go/Packages/go.mod

@@ -0,0 +1,5 @@
+module github.com/github/codeql-go/ql/test/library-tests/semmle/go/main
+
+go 1.13
+
+require github.com/nonexistent-test-pkg v0.0.0-20200203000000-0000000000000

ql/test/library-tests/semmle/go/Packages/main.go

@@ -0,0 +1,12 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/nonexistent-test-pkg"
+)
+
+func main() {
+	pkg.Foo()
+	fmt.Println("")
+}

ql/test/library-tests/semmle/go/Packages/vendor/github.com/nonexistent-test-pkg/README.md

@@ -0,0 +1 @@
+This is a simple stub package, strictly for use in query testing.

ql/test/library-tests/semmle/go/Packages/vendor/github.com/nonexistent-test-pkg/pkg.go

@@ -0,0 +1,5 @@
+package pkg
+
+func Foo() string {
+	return "foo"
+}

ql/test/library-tests/semmle/go/Packages/vendor/modules.txt

@@ -0,0 +1,2 @@
+# github.com/nonexistent-test-pkg v0.0.0-20200203000000-0000000000000
+github.com/nonexistent-test-package