fix: alias can't have a first digit

dave · Aug 28, 2020 · c4ea171 · c4ea171
1 parent ef3c850
commit c4ea171
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Showing 3 changed files with 12 additions and 0 deletions.
diff --git a/go.mod b/go.mod
@@ -0,0 +1,3 @@
+module github.com/dave/jennifer
+
+go 1.15
diff --git a/jen/file.go b/jen/file.go
@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"regexp"
 	"strings"
+	"unicode"
+	"unicode/utf8"
 )
 
 // NewFile Creates a new file, with the specified package name.
@@ -240,5 +242,10 @@ func guessAlias(path string) string {
 	importsRegex := regexp.MustCompile(`[^a-z0-9]`)
 	alias = importsRegex.ReplaceAllString(alias, "")
 
+	// can't have a first digit, per Go identifier rules, so just skip them
+	for firstRune, runeLen := utf8.DecodeRuneInString(alias); unicode.IsDigit(firstRune); firstRune, runeLen = utf8.DecodeRuneInString(alias) {
+		alias = alias[runeLen:]
+	}
+
 	return alias
 }
diff --git a/jen/file_test.go b/jen/file_test.go
@@ -20,6 +20,8 @@ func TestGuessAlias(t *testing.T) {
 		"a/b-c.d":       "bcd",
 		"a/bb-ccc.dddd": "bbcccdddd",
 		"a/foo-go":      "foogo",
+		"123a":          "a",
+		"a/321a.b":      "ab",
 	}
 	for path, expected := range data {
 		if guessAlias(path) != expected {