superfuous-else handles more cases (#24)

* Adds rule superfluous-else (an extension of indent-error-flow)

* Fix superfluous-else rule struct namming.

* Adds superfuous-else rule to the rules table

* Adds confusing-naming rule

* adds multifile test

* clean-up

* fix config.go

* superflous-else now detects "jumps" caused by functions like os.Exit and log.Fatal

fixtures/superfluous-else.go

@@ -4,6 +4,7 @@
 package pkg
 
 import (
+	"os"
 	"fmt"
 	"log"
 )
@@ -71,3 +72,86 @@ func j(f func() bool) string {
 
 	return "ok"
 }
+
+func fatal1() string {
+		if f() {
+			a := 1
+			log.Fatal("x")
+		} else { // MATCH /if block ends with call to log.Fatal function, so drop this else and outdent its block/
+			log.Printf("non-positive")
+		}
+	return "ok"
+}
+
+func fatal2() string {
+		if f() {
+			a := 1
+			log.Fatalf("x")
+		} else { // MATCH /if block ends with call to log.Fatalf function, so drop this else and outdent its block/
+			log.Printf("non-positive")
+		}
+	return "ok"
+}
+
+func fatal3() string {
+		if f() {
+			a := 1
+			log.Fatalln("x")
+		} else { // MATCH /if block ends with call to log.Fatalln function, so drop this else and outdent its block/
+			log.Printf("non-positive")
+		}
+	return "ok"
+}
+
+func exit1() string {
+		if f() {
+			a := 1
+			os.Exit(2)
+		} else { // MATCH /if block ends with call to os.Exit function, so drop this else and outdent its block/
+			log.Printf("non-positive")
+		}
+	return "ok"
+}
+
+func Panic1() string {
+		if f() {
+			a := 1
+			log.Panic(2)
+		} else { // MATCH /if block ends with call to log.Panic function, so drop this else and outdent its block/
+			log.Printf("non-positive")
+		}
+	return "ok"
+}
+
+func Panic2() string {
+		if f() {
+			a := 1
+			log.Panicf(2)
+		} else { // MATCH /if block ends with call to log.Panicf function, so drop this else and outdent its block/
+			log.Printf("non-positive")
+		}
+	return "ok"
+}
+
+func Panic3() string {
+		if f() {
+			a := 1
+			log.Panicln(2)
+		} else { // MATCH /if block ends with call to log.Panicln function, so drop this else and outdent its block/
+			log.Printf("non-positive")
+		}
+	return "ok"
+}
+
+// noreg_19 no-regression test for issue #19 (https://github.com/mgechev/revive/issues/19)
+func noreg_19(f func() bool, x int) string {
+	if err == author.ErrCourseNotFound {
+		break
+	} else if err == author.ErrCourseAccess {
+		// side effect
+	} else if err == author.AnotherError {
+		os.Exit(1) // "okay"
+	} else {
+		// side effect
+	}
+}

rule/superfluous-else.go

@@ -1,6 +1,7 @@
 package rule
 
 import (
+	"fmt"
 	"go/ast"
 	"go/token"
 
@@ -13,12 +14,23 @@ type SuperfluousElseRule struct{}
 // Apply applies the rule to given file.
 func (r *SuperfluousElseRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
 	var failures []lint.Failure
-
 	onFailure := func(failure lint.Failure) {
 		failures = append(failures, failure)
 	}
 
-	w := lintSuperfluousElse{make(map[*ast.IfStmt]bool), onFailure}
+	var branchingFunctions = map[string]map[string]bool{
+		"os": map[string]bool{"Exit": true},
+		"log": map[string]bool{
+			"Fatal":   true,
+			"Fatalf":  true,
+			"Fatalln": true,
+			"Panic":   true,
+			"Panicf":  true,
+			"Panicln": true,
+		},
+	}
+
+	w := lintSuperfluousElse{make(map[*ast.IfStmt]bool), onFailure, branchingFunctions}
 	ast.Walk(w, file.AST)
 	return failures
 }
@@ -31,6 +43,7 @@ func (r *SuperfluousElseRule) Name() string {
 type lintSuperfluousElse struct {
 	ignore             map[*ast.IfStmt]bool
 	onFailure          func(lint.Failure)
+	branchingFunctions map[string]map[string]bool
 }
 
 func (w lintSuperfluousElse) Visit(node ast.Node) ast.Visitor {
@@ -39,6 +52,9 @@ func (w lintSuperfluousElse) Visit(node ast.Node) ast.Visitor {
 		return w
 	}
 	if w.ignore[ifStmt] {
+		if elseif, ok := ifStmt.Else.(*ast.IfStmt); ok {
+			w.ignore[elseif] = true
+		}
 		return w
 	}
 	if elseif, ok := ifStmt.Else.(*ast.IfStmt); ok {
@@ -64,18 +80,36 @@ func (w lintSuperfluousElse) Visit(node ast.Node) ast.Visitor {
 	}
 
 	lastStmt := ifStmt.Body.List[len(ifStmt.Body.List)-1]
-	if stmt, ok := lastStmt.(*ast.BranchStmt); ok {
+	switch stmt := lastStmt.(type) {
+	case *ast.BranchStmt:
 		token := stmt.Tok.String()
 		if token != "fallthrough" {
-			w.onFailure(lint.Failure{
-				Confidence: 1,
-				Node:       ifStmt.Else,
-				Category:   "indent",
-				URL:        "#indent-error-flow",
-				Failure:    "if block ends with a " + token + " statement, so drop this else and outdent its block" + extra,
-			})
+			w.onFailure(newFailure(ifStmt.Else, "if block ends with a "+token+" statement, so drop this else and outdent its block"+extra))
+		}
+	case *ast.ExprStmt:
+		if ce, ok := stmt.X.(*ast.CallExpr); ok { // it's a function call
+			if fc, ok := ce.Fun.(*ast.SelectorExpr); ok {
+				if id, ok := fc.X.(*ast.Ident); ok {
+					fn := fc.Sel.Name
+					pkg := id.Name
+					if w.branchingFunctions[pkg][fn] { // it's a call to a branching function
+						w.onFailure(
+							newFailure(ifStmt.Else, fmt.Sprintf("if block ends with call to %s.%s function, so drop this else and outdent its block%s", pkg, fn, extra)))
+					}
+				}
+			}
 		}
 	}
 
 	return w
 }
+
+func newFailure(node ast.Node, msg string) lint.Failure {
+	return lint.Failure{
+		Confidence: 1,
+		Node:       node,
+		Category:   "indent",
+		URL:        "#indent-error-flow",
+		Failure:    msg,
+	}
+}