Support matching against package-qualified name as well

internal/analyzer/analyzer.go

@@ -48,23 +48,35 @@ func run(pass *analysis.Pass) (interface{}, error) {
 func reportImported(pass *analysis.Pass, expr ast.Expr, checkRE *regexp.Regexp, prefix string) {
 	switch x := expr.(type) {
 	case *ast.SelectorExpr:
-		if !checkRE.MatchString(x.Sel.Name) {
-			return
-		}
-
 		selectIdent, ok := x.X.(*ast.Ident)
 		if !ok {
 			return
 		}
 
+		var pkgPath string
 		if selectObj, ok := pass.TypesInfo.Uses[selectIdent]; ok {
-			if pkg, ok := selectObj.(*types.PkgName); !ok || pkg.Imported() == pass.Pkg {
+			pkg, ok := selectObj.(*types.PkgName)
+			if !ok || pkg.Imported() == pass.Pkg {
 				return
 			}
+			pkgPath = pkg.Imported().Path()
 		}
 
-		pass.Reportf(expr.Pos(), "%s variable %s in other package %s", prefix, x.Sel.Name, selectIdent.Name)
+		matches := false
+		if checkRE.MatchString(x.Sel.Name) {
+			matches = true
+		}
+		if !matches {
+			// Expression may include a package name, so check that too. Support was added later so we check
+			// just name and qualified name separately for compatibility.
+			if checkRE.MatchString(pkgPath + "." + x.Sel.Name) {
+				matches = true
+			}
+		}
 
+		if matches {
+			pass.Reportf(expr.Pos(), "%s variable %s in other package %s", prefix, x.Sel.Name, selectIdent.Name)
+		}
 	case *ast.Ident:
 		use, ok := pass.TypesInfo.Uses[x].(*types.Var)
 		if !ok {

internal/analyzer/analyzer_test.go

@@ -24,6 +24,10 @@ func TestAnalyzer(t *testing.T) {
 			dir:     "defaultclient",
 			pattern: `^(DefaultClient|DefaultTransport)$`,
 		},
+		{
+			dir:     "packagepattern",
+			pattern: `^(net/http\.DefaultClient|DefaultTransport)$`,
+		},
 	}
 
 	wd, err := os.Getwd()

testdata/defaultclient/src/a/a.go

@@ -1,10 +1,9 @@
 package a
 
 import (
+	"config"
 	"io"
 	"net/http"
-
-	"config"
 )
 
 var DefaultClient = &http.Client{}

testdata/defaults/src/a/a.go

@@ -2,16 +2,12 @@ package a
 
 import (
 	"b"
-
-	"errors"
-	"io"
-)
-import cc "c"
-
-import (
+	cc "c"
 	"d"
 	"d/e"
 	"d/e/f"
+	"errors"
+	"io"
 )
 
 var st = struct {

testdata/packagepattern/src/a/a.go

@@ -0,0 +1,19 @@
+package a
+
+import (
+	"config"
+	"io"
+	"net/http"
+)
+
+var DefaultClient = &http.Client{}
+
+func reassignPattern() {
+	io.EOF = nil
+
+	config.DefaultClient = nil
+	DefaultClient = nil
+
+	http.DefaultClient = nil    // want "reassigning variable"
+	http.DefaultTransport = nil // want "reassigning variable"
+}

testdata/packagepattern/src/config/config.go

@@ -0,0 +1,5 @@
+package config
+
+import "net/http"
+
+var DefaultClient = &http.Client{}