From 45ae9f049483ea3807969ef534025a0d63518f33 Mon Sep 17 00:00:00 2001
From: Markus Opolka <markus.opolka@netways.de>
Date: Mon, 31 Jul 2023 11:31:07 +0200
Subject: [PATCH] Feature: Ignore comments in getLines() (#14)

* Add go.mod

* Add basic unittest

* Add option to ignore comments in getLines()

* Extend test coverage
---
 go.mod       |   3 ++
 main.go      |  28 ++++++++++++--
 main_test.go | 105 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 132 insertions(+), 4 deletions(-)
 create mode 100644 go.mod
 create mode 100644 main_test.go

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..17fa745
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module github.com/ultraware/funlen
+
+go 1.20
diff --git a/main.go b/main.go
index 2ba3530..b68ddb9 100644
--- a/main.go
+++ b/main.go
@@ -13,7 +13,7 @@ const (
 )
 
 // Run runs this linter on the provided code
-func Run(file *ast.File, fset *token.FileSet, lineLimit, stmtLimit int) []Message {
+func Run(file *ast.File, fset *token.FileSet, lineLimit int, stmtLimit int, ignoreComments bool) []Message {
 	if lineLimit == 0 {
 		lineLimit = defaultLineLimit
 	}
@@ -21,6 +21,8 @@ func Run(file *ast.File, fset *token.FileSet, lineLimit, stmtLimit int) []Messag
 		stmtLimit = defaultStmtLimit
 	}
 
+	cmap := ast.NewCommentMap(fset, file, file.Comments)
+
 	var msgs []Message
 	for _, f := range file.Decls {
 		decl, ok := f.(*ast.FuncDecl)
@@ -36,7 +38,7 @@ func Run(file *ast.File, fset *token.FileSet, lineLimit, stmtLimit int) []Messag
 		}
 
 		if lineLimit > 0 {
-			if lines := getLines(fset, decl); lines > lineLimit {
+			if lines := getLines(fset, decl, cmap.Filter(decl), ignoreComments); lines > lineLimit {
 				msgs = append(msgs, makeLineMessage(fset, decl.Name, lines, lineLimit))
 			}
 		}
@@ -65,8 +67,26 @@ func makeStmtMessage(fset *token.FileSet, funcInfo *ast.Ident, stmts, stmtLimit
 	}
 }
 
-func getLines(fset *token.FileSet, f *ast.FuncDecl) int { // nolint: interfacer
-	return fset.Position(f.End()).Line - fset.Position(f.Pos()).Line - 1
+func getLines(fset *token.FileSet, f *ast.FuncDecl, cmap ast.CommentMap, ignoreComments bool) int { // nolint: interfacer
+	var lineCount int
+	var commentCount int
+
+	lineCount = fset.Position(f.End()).Line - fset.Position(f.Pos()).Line - 1
+
+	if !ignoreComments {
+		return lineCount
+	}
+
+	for _, c := range cmap.Comments() {
+		// If the CommenGroup's lines are inside the function
+		// count how many comments are in the CommentGroup
+		if (fset.Position(c.Pos()).Line > fset.Position(f.Pos()).Line) &&
+			(fset.Position(c.End()).Line < fset.Position(f.End()).Line) {
+			commentCount += len(c.List)
+		}
+	}
+
+	return lineCount - commentCount
 }
 
 func parseStmts(s []ast.Stmt) (total int) {
diff --git a/main_test.go b/main_test.go
new file mode 100644
index 0000000..1e0ad9c
--- /dev/null
+++ b/main_test.go
@@ -0,0 +1,105 @@
+package funlen
+
+import (
+	"go/parser"
+	"go/token"
+	"strings"
+	"testing"
+)
+
+func TestRunTable(t *testing.T) {
+	testcases := map[string]struct {
+		input     string
+		expected  string
+		lineLimit int
+		stmtLimit int
+	}{
+		"too-many-statements": {
+			input: `package main
+	func main() {
+	print("Hello, world!")
+	print("Hello, world!")}`,
+			expected:  "Function 'main' has too many statements (2 > 1)",
+			lineLimit: 1,
+			stmtLimit: 1,
+		},
+		"too-many-lines": {
+			input: `package main
+	import "fmt"
+	func main() {
+	print("main!")
+	print("is!")
+	print("too!")
+	print("long")}`,
+			expected:  "Function 'main' is too long (3 > 1)",
+			lineLimit: 1,
+			stmtLimit: 10,
+		},
+		"too-many-statements-inline-func": {
+			input: `package main
+	func main() {
+	print("Hello, world!")
+	if true {
+		y := []int{1,2,3,4}
+		for k, v := range y {
+			f := func() { print("test") }
+			f()
+		}
+	}
+	print("Hello, world!")}`,
+			expected:  "Function 'main' has too many statements (8 > 1)",
+			lineLimit: 1,
+			stmtLimit: 1,
+		},
+	}
+
+	for name, test := range testcases {
+		t.Run(name, func(t *testing.T) {
+			fset := token.NewFileSet()
+			f, err := parser.ParseFile(fset, "", test.input, parser.ParseComments)
+
+			if err != nil {
+				t.Error("\nActual: ", err, "\n Did not expected error")
+			}
+
+			r := Run(f, fset, test.lineLimit, test.stmtLimit, false)
+			actual := r[0].Message
+
+			if !strings.Contains(actual, test.expected) {
+				t.Error("\nActual: ", actual, "\nExpected: ", test.expected)
+			}
+		})
+	}
+}
+
+func TestRunIgnoresComments(t *testing.T) {
+
+	input := `package main
+	func main() {
+	// Comment 1
+	// Comment 2
+	// Comment 3
+	print("Hello, world!")}
+	// Comment Doc
+	func unittest() {
+	// Comment 1
+	// Comment 2
+	print("Hello, world!")}
+	// Comment 3`
+
+	lineLimit := 2
+	stmtLimit := 2
+
+	fset := token.NewFileSet()
+	f, err := parser.ParseFile(fset, "", input, parser.ParseComments)
+
+	if err != nil {
+		t.Error("\nActual: ", err, "\n Did not expected error")
+	}
+
+	r := Run(f, fset, lineLimit, stmtLimit, true)
+
+	if len(r) > 0 {
+		t.Error("\nActual: ", r, "\nExpected no lint errors")
+	}
+}