Refactor main.go:run

Update the `run` function in `main.go` to reduce its cognitive
complexity as well reduce code duplication (in terms of printing
problems as well as parsing and processing files). Additionally, the
argument name has been updated from the old and outdated `wd` (short for
"working directory") to "target" (aligning it with how it's called).

Signed-off-by: Eric Cornelissen <ericornelissen@gmail.com>

main.go

@@ -92,98 +92,97 @@ func main() {
 	}
 }
 
-func run(wd string) (hasProblems bool, err error) {
-	if data, err := os.ReadFile(wd); err == nil {
-		manifest, err := parseManifest(data)
-		if err != nil {
-			return hasProblems, err
-		}
-
-		problems := processManifest(&manifest)
-		if cnt := len(problems); cnt > 0 {
-			fmt.Printf("Detected %d problem(s) in '%s':\n", cnt, wd)
-			for _, problem := range problems {
-				fmt.Println("  ", problem)
-			}
-		}
+func run(target string) (hasProblems bool, err error) {
+	stat, err := os.Stat(target)
+	if err != nil {
+		return hasProblems, fmt.Errorf("could not process %s: %v", target, err)
+	}
 
-		if len(problems) > 0 {
-			// don't try to parse the file as an Actions workflow if it was already
-			// successfully analyzed as an Action manifest.
-			return true, nil
+	if stat.IsDir() {
+		if problems, err := tryManifest(path.Join(target, "action.yml")); err != nil {
+			return hasProblems, err
+		} else {
+			hasProblems = len(problems) > 0
+			printProblems("action.yml", problems)
 		}
 
-		workflow, err := parseWorkflow(data)
+		workflowsDir := path.Join(target, ".github", "workflows")
+		workflows, err := os.ReadDir(workflowsDir)
 		if err != nil {
-			return hasProblems, err
+			return hasProblems, fmt.Errorf("could not read workflows directory: %v", err)
 		}
 
-		problems = processWorkflow(&workflow)
-		if cnt := len(problems); cnt > 0 {
-			fmt.Printf("Detected %d problem(s) in '%s':\n", cnt, wd)
-			for _, problem := range problems {
-				fmt.Println("  ", problem)
+		for _, entry := range workflows {
+			if entry.Type().IsDir() {
+				continue
 			}
-		}
 
-		return len(problems) > 0, nil
-	}
+			if path.Ext(entry.Name()) != ".yml" {
+				continue
+			}
 
-	if data, err := os.ReadFile(path.Join(wd, "action.yml")); err == nil {
-		manifest, err := parseManifest(data)
-		if err != nil {
+			workflowPath := path.Join(workflowsDir, entry.Name())
+			if problems, err := tryWorkflow(workflowPath); err != nil {
+				fmt.Printf("Could not process workflow %s: %v\n", entry.Name(), err)
+			} else {
+				hasProblems = len(problems) > 0
+				printProblems(entry.Name(), problems)
+			}
+		}
+	} else {
+		if problems, err := tryManifest(target); err != nil {
 			return hasProblems, err
+		} else {
+			hasProblems = len(problems) > 0
+			printProblems(target, problems)
 		}
 
-		problems := processManifest(&manifest)
-		if cnt := len(problems); cnt > 0 {
-			hasProblems = true
-			fmt.Printf("Detected %d problem(s) in 'action.yml':\n", cnt)
-			for _, problem := range problems {
-				fmt.Println("  ", problem)
-			}
+		if problems, err := tryWorkflow(target); err != nil {
+			return hasProblems, err
+		} else {
+			hasProblems = len(problems) > 0
+			printProblems(target, problems)
 		}
 	}
 
-	workflowsDir := path.Join(wd, ".github", "workflows")
-	workflows, err := os.ReadDir(workflowsDir)
+	return hasProblems, nil
+}
+
+func tryManifest(manifestPath string) (problems []string, err error) {
+	data, err := os.ReadFile(manifestPath)
+	if err != nil {
+		return nil, nil
+	}
+
+	manifest, err := parseManifest(data)
 	if err != nil {
-		return hasProblems, fmt.Errorf("could not read workflows directory: %v", err)
+		return nil, err
 	}
 
-	for _, entry := range workflows {
-		if entry.Type().IsDir() {
-			continue
-		}
+	return processManifest(&manifest), nil
+}
 
-		if path.Ext(entry.Name()) != ".yml" {
-			continue
-		}
+func tryWorkflow(workflowPath string) (problems []string, err error) {
+	data, err := os.ReadFile(workflowPath)
+	if err != nil {
+		return nil, err
+	}
 
-		workflowPath := path.Join(workflowsDir, entry.Name())
-		data, err := os.ReadFile(workflowPath)
-		if err != nil {
-			fmt.Printf("Could not read %s: %v\n", entry.Name(), err)
-			continue
-		}
+	workflow, err := parseWorkflow(data)
+	if err != nil {
+		return nil, err
+	}
 
-		workflow, err := parseWorkflow(data)
-		if err != nil {
-			fmt.Printf("Could not parse %s: %v\n", entry.Name(), err)
-			continue
-		}
+	return processWorkflow(&workflow), nil
+}
 
-		problems := processWorkflow(&workflow)
-		if cnt := len(problems); cnt > 0 {
-			hasProblems = true
-			fmt.Printf("Detected %d problem(s) in '%s':\n", cnt, entry.Name())
-			for _, problem := range problems {
-				fmt.Println("  ", problem)
-			}
+func printProblems(file string, problems []string) {
+	if cnt := len(problems); cnt > 0 {
+		fmt.Printf("Detected %d problem(s) in '%s':\n", cnt, file)
+		for _, problem := range problems {
+			fmt.Println("  ", problem)
 		}
 	}
-
-	return hasProblems, nil
 }
 
 func getTargets(argv []string) ([]string, error) {