From 3f1109b1eb10cae482ac8feb1853cc9e5ab8499a Mon Sep 17 00:00:00 2001
From: Frederik Zipp <fzipp@gmx.de>
Date: Tue, 22 Mar 2022 18:19:27 +0100
Subject: [PATCH] ignore 'vendor' and 'testdata' directories and directories
 with names that begin with '.' or '_'

Fixes #42
---
 CHANGELOG.md                        |  5 +++++
 analyze.go                          | 14 ++++++++++++++
 analyze_test.go                     |  4 ++++
 testdata/ignore/.dotname/file.go    |  3 +++
 testdata/ignore/_underscore/file.go |  3 +++
 testdata/ignore/testdata/file.go    |  3 +++
 testdata/ignore/vendor/file.go      |  3 +++
 7 files changed, 35 insertions(+)
 create mode 100644 testdata/ignore/.dotname/file.go
 create mode 100644 testdata/ignore/_underscore/file.go
 create mode 100644 testdata/ignore/testdata/file.go
 create mode 100644 testdata/ignore/vendor/file.go

diff --git a/CHANGELOG.md b/CHANGELOG.md
index efbc9fe..9bf352e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+### Changed
+- Ignore `vendor` and `testdata` directories and directories with names
+  that begin with `.` or `_`
+
 ## [0.4.0] - 2021-12-19
 ### Added
 - Support method receivers with type parameters introduced in Go 1.18
diff --git a/analyze.go b/analyze.go
index 1f3479a..3a448b6 100644
--- a/analyze.go
+++ b/analyze.go
@@ -41,6 +41,9 @@ func Analyze(paths []string, ignore *regexp.Regexp) Stats {
 
 func analyzeDir(dirname string, ignore *regexp.Regexp, stats Stats) Stats {
 	filepath.WalkDir(dirname, func(path string, entry fs.DirEntry, err error) error {
+		if isSkipDir(entry) {
+			return filepath.SkipDir
+		}
 		if err == nil && isGoFile(entry) {
 			stats = analyzeFile(path, ignore, stats)
 		}
@@ -49,6 +52,17 @@ func analyzeDir(dirname string, ignore *regexp.Regexp, stats Stats) Stats {
 	return stats
 }
 
+var skipDirs = map[string]bool{
+	"testdata": true,
+	"vendor":   true,
+}
+
+func isSkipDir(entry fs.DirEntry) bool {
+	return entry.IsDir() && (skipDirs[entry.Name()] ||
+		strings.HasPrefix(entry.Name(), ".") ||
+		strings.HasPrefix(entry.Name(), "_"))
+}
+
 func isGoFile(entry fs.DirEntry) bool {
 	return !entry.IsDir() && strings.HasSuffix(entry.Name(), ".go")
 }
diff --git a/analyze_test.go b/analyze_test.go
index 8a790a0..3ddca4f 100644
--- a/analyze_test.go
+++ b/analyze_test.go
@@ -75,6 +75,10 @@ func TestAnalyze(t *testing.T) {
 			`1 directory b testdata/directory/file2.go:3:1
 1 directory a testdata/directory/file1.go:3:1`,
 		},
+		{
+			[]string{"testdata/ignore"},
+			"",
+		},
 	}
 
 	for _, tt := range tests {
diff --git a/testdata/ignore/.dotname/file.go b/testdata/ignore/.dotname/file.go
new file mode 100644
index 0000000..ccc228b
--- /dev/null
+++ b/testdata/ignore/.dotname/file.go
@@ -0,0 +1,3 @@
+package dotname
+
+func a() {}
diff --git a/testdata/ignore/_underscore/file.go b/testdata/ignore/_underscore/file.go
new file mode 100644
index 0000000..53f97fc
--- /dev/null
+++ b/testdata/ignore/_underscore/file.go
@@ -0,0 +1,3 @@
+package underscore
+
+func a() {}
diff --git a/testdata/ignore/testdata/file.go b/testdata/ignore/testdata/file.go
new file mode 100644
index 0000000..8eb84ea
--- /dev/null
+++ b/testdata/ignore/testdata/file.go
@@ -0,0 +1,3 @@
+package testdata
+
+func a() {}
diff --git a/testdata/ignore/vendor/file.go b/testdata/ignore/vendor/file.go
new file mode 100644
index 0000000..9bb5cd0
--- /dev/null
+++ b/testdata/ignore/vendor/file.go
@@ -0,0 +1,3 @@
+package vendor
+
+func a() {}