fix: handle file not found (#6)

* fix: handle file not found

Signed-off-by: Carlos Alexandro Becker <caarlos0@gmail.com>

* refactor: Refactor prefix helper functions.

* fix: Fix file not found error for escaped patterns.

Co-authored-by: Erik Geiser <erik.geiser@posteo.net>

glob.go

@@ -72,12 +72,17 @@ func doGlob(pattern string, options *globOptions) ([]string, error) { // nolint:
 
 	prefixInfo, err := fs.Stat(prefix)
 	if os.IsNotExist(err) {
-		// if the prefix does not exist, the whole
-		// glob pattern won't match anything
+		if !ContainsMatchers(pattern) {
+			// glob contains no dynamic matchers so prefix is the file name that
+			// the glob references directly. When the glob explicitly references
+			// a single non-existing file, return an error for the user to check.
+			return []string{}, fmt.Errorf("matching %q: %w", prefix, os.ErrNotExist)
+		}
+
 		return []string{}, nil
 	}
 	if err != nil {
-		return nil, fmt.Errorf("stat prefix: %w", err)
+		return nil, fmt.Errorf("stat static prefix %q: %w", prefix, err)
 	}
 
 	if !prefixInfo.IsDir() {

glob_test.go

@@ -1,6 +1,8 @@
 package fileglob
 
 import (
+	"errors"
+	"os"
 	"path/filepath"
 	"testing"
 
@@ -131,8 +133,15 @@ func TestGlob(t *testing.T) { // nolint:funlen
 			"./a/nope.txt",
 			"./a/b/dc",
 		}, nil)))
-		require.NoError(t, err)
-		require.Equal(t, []string{}, matches)
+		require.EqualError(t, err, "matching \"a/b/d\": file does not exist")
+		require.True(t, errors.Is(err, os.ErrNotExist))
+		require.Empty(t, matches)
+	})
+
+	t.Run("escaped direct no match", func(t *testing.T) {
+		matches, err := Glob("a/\\{b\\}", WithFs(testFs(t, nil, nil)))
+		require.EqualError(t, err, "matching \"a/{b}\": file does not exist")
+		require.Empty(t, matches)
 	})
 
 	t.Run("no matches", func(t *testing.T) {

prefix.go

@@ -24,32 +24,35 @@ func ContainsMatchers(pattern string) bool {
 		return false
 	}
 
-	containsMatchers, _ := containsMatchers(rootNode)
-	return containsMatchers
+	_, isStatic := staticText(rootNode)
+	return !isStatic
 }
 
-func containsMatchers(node *ast.Node) (result bool, staticText string) {
+// staticText returns the static string matcher represented by the AST unless
+// it contains dynamic matchers (wildcards, etc.). In this case the ok return
+// value is false.
+func staticText(node *ast.Node) (text string, ok bool) {
 	// nolint:exhaustive
 	switch node.Kind {
 	case ast.KindPattern:
 		text := ""
 
 		for _, child := range node.Children {
-			cm, staticText := containsMatchers(child)
-			if cm {
-				return true, ""
+			childText, ok := staticText(child)
+			if !ok {
+				return "", false
 			}
 
-			text += staticText
+			text += childText
 		}
 
-		return false, text
+		return text, true
 	case ast.KindText:
-		return false, node.Value.(ast.Text).Text
+		return node.Value.(ast.Text).Text, true
 	case ast.KindNothing:
-		return false, ""
+		return "", true
 	default:
-		return true, ""
+		return "", false
 	}
 }
 
@@ -73,12 +76,12 @@ func staticPrefix(pattern string) (string, error) {
 			return "", fmt.Errorf("parse glob pattern: %w", err)
 		}
 
-		cm, staticText := containsMatchers(rootNode)
-		if cm {
+		staticPart, ok := staticText(rootNode)
+		if !ok {
 			break
 		}
 
-		prefix = filepath.Join(prefix, staticText)
+		prefix = filepath.Join(prefix, staticPart)
 	}
 
 	if prefix == "" {