analysis: create header missing diagnostics on package pos (#9)

Author: joshuasing

analysis.go

@@ -179,7 +179,7 @@ func (a *analyzer) checkFile(pass *analysis.Pass, file *ast.File) error {
 			return fmt.Errorf("create %s header: %w", filename, err)
 		}
 		pass.Report(analysis.Diagnostic{
-			Pos:      file.FileStart,
+			Pos:      file.Package,
 			Category: analyzerName,
 			Message:  "missing license header",
 			SuggestedFixes: []analysis.SuggestedFix{{

analysis_test.go

@@ -52,6 +52,13 @@ func TestAnalyzer(t *testing.T) {
 			t.Fatalf("NewAnalyzer() err = %v", err)
 		}
 
+		// Test with sources containing build directives.
+		t.Run("builddirective", func(t *testing.T) {
+			t.Parallel()
+			packageDir := filepath.Join(analysistest.TestData(), "src/builddirective/")
+			_ = analysistest.Run(t, packageDir, a)
+		})
+
 		// Different header contains a file with a different license header.
 		// This license header should stay as-is and should not be modified.
 		t.Run("differentheader", func(t *testing.T) {

testdata/src/builddirective/main.go

@@ -0,0 +1,3 @@
+//go:build !foo
+
+package main // want "missing license header"

testdata/src/builddirective/main.go.golden

@@ -0,0 +1,5 @@
+// Copyright (c) 2025 Test
+
+//go:build !foo
+
+package main // want "missing license header"

testdata/src/packagecomment/main.go

@@ -1,3 +1,3 @@
-// Package packagecomment has a package-level doc comment. This comment should // want "missing license header"
+// Package packagecomment has a package-level doc comment. This comment should
 // not affect the generation of a license header above it.
-package packagecomment
+package packagecomment // want "missing license header"

testdata/src/packagecomment/main.go.golden

@@ -1,5 +1,5 @@
 // Copyright (c) 2025 Test
 
-// Package packagecomment has a package-level doc comment. This comment should // want "missing license header"
+// Package packagecomment has a package-level doc comment. This comment should
 // not affect the generation of a license header above it.
-package packagecomment
+package packagecomment // want "missing license header"