Add -include-generated to report in generated files

README.md

@@ -23,6 +23,11 @@ constable ./...
 
 constable skips files that carry the standard generated-code comment, `// Code generated ... DO NOT EDIT.`.
 A diagnostic in such a file is not actionable because the next run of the generator overwrites the file.
+Set `-include-generated` to report in them anyway,
+
+```sh
+constable -include-generated ./...
+```
 
 ## Example
 

cmd/constable/main_test.go

@@ -400,6 +400,44 @@ func TestCLIEmbeddedAnalyzersSkipGeneratedFiles(t *testing.T) {
 	assert.Empty(t, output)
 }
 
+func TestCLIIncludeGenerated(t *testing.T) {
+	binary := buildBinary(t)
+	moduleDir := writeModule(t, module{
+		GoMod: []string{
+			"module example.com/generated",
+			"",
+			"go 1.26",
+		},
+		Files: map[string][]string{"gen.go": {
+			"// Code generated by hand. DO NOT EDIT.",
+			"",
+			"package generated",
+			"",
+			"import \"os\"",
+			"",
+			"func F() {",
+			"\tos.Remove(\"x\")",
+			"}",
+			"",
+			"//constable:nonmutating",
+			"func G(p *int) {",
+			"\t*p = 1",
+			"}",
+		}},
+	})
+
+	output, err := runConstable(t, binary, moduleDir)
+	require.NoError(t, err, output)
+	assert.Empty(t, output)
+
+	// One flag turns the skip off for the analyzers that constable owns and for
+	// the analyzers that it embeds.
+	output, err = runConstable(t, binary, moduleDir, "-include-generated")
+	require.Error(t, err, output)
+	assert.Contains(t, output, "unchecked error")
+	assert.Contains(t, output, "//constable:nonmutating function mutates pointer parameter p")
+}
+
 func buildBinary(t *testing.T) string {
 	t.Helper()
 

internal/driver/driver.go

@@ -25,6 +25,8 @@ import (
 	"golang.org/x/tools/go/analysis/checker"
 	"golang.org/x/tools/go/analysis/unitchecker"
 	"golang.org/x/tools/go/packages"
+
+	"github.com/nnutter/constable/internal/generated"
 )
 
 // Options controls driver output.
@@ -152,9 +154,12 @@ func Main(version string, hooks Hooks, analyzers ...*analysis.Analyzer) {
 	flag.BoolVar(&opts.Fix, "fix", false, "apply all suggested fixes")
 	flag.BoolVar(&opts.Diff, "diff", false, "with -fix, don't update the files, but print a unified diff")
 	flag.BoolVar(&opts.IncludeTests, "test", true, "indicates whether test files should be analyzed, too")
+	includeGenerated := flag.Bool("include-generated", false, "report in generated files, which constable skips by default")
 
 	flag.Parse()
 
+	generated.Include(*includeGenerated)
+
 	if *printFlags {
 		writeFlagsJSON()
 		return

internal/generated/generated.go

@@ -4,12 +4,24 @@ package generated
 
 import "go/ast"
 
+// include reports whether analyzers report in generated files.
+var include bool
+
+// Include makes analyzers report in generated files when enabled is true.
+//
+// The driver sets it from -include-generated, so every analyzer follows one
+// answer without carrying a flag of its own.
+func Include(enabled bool) {
+	include = enabled
+}
+
 // Skipped reports whether analyzers omit the diagnostics of file.
 //
 // A diagnostic in a generated file is not actionable because the next run of
 // the generating tool overwrites the file. The mark is the Go convention,
 // "// Code generated <tool> DO NOT EDIT.", so an author controls it with the
-// comment alone.
+// comment alone. Include overrides the rule for a run that wants every
+// diagnostic.
 func Skipped(file *ast.File) bool {
-	return ast.IsGenerated(file)
+	return !include && ast.IsGenerated(file)
 }

internal/generated/skip_test.go

@@ -32,3 +32,10 @@ var reportFuncs = &analysis.Analyzer{
 func TestSkip(t *testing.T) {
 	analysistest.Run(t, analysistest.TestData(), generated.Skip(reportFuncs), "g")
 }
+
+func TestSkipWithInclude(t *testing.T) {
+	generated.Include(true)
+	t.Cleanup(func() { generated.Include(false) })
+
+	analysistest.Run(t, analysistest.TestData(), generated.Skip(reportFuncs), "h")
+}

internal/generated/testdata/src/h/h.go

@@ -0,0 +1,3 @@
+package h
+
+func Gen() {} // want `func Gen`