mime: ignore non-extension globs2 entries

Change-Id: Ic2315b593dca5648c02f793b7650b5936a997bff
GitHub-Last-Rev: ee55edcf08
GitHub-Pull-Request: golang/go#51226
Reviewed-on: https://go-review.googlesource.com/c/go/+/386334
Reviewed-by: Damien Neil <dneil@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

src/mime/testdata/test.types.globs2

@@ -6,4 +6,6 @@
 # mime package test for globs2
 50:document/test:*.t3
 50:example/test:*.t4
+50:text/plain:*,v
+50:application/x-trash:*~
 30:example/do-not-use:*.t4

src/mime/type_unix.go

@@ -40,11 +40,11 @@ func loadMimeGlobsFile(filename string) error {
 
 	scanner := bufio.NewScanner(f)
 	for scanner.Scan() {
-		// Each line should be of format: weight:mimetype:*.ext
+		// Each line should be of format: weight:mimetype:*.ext[:morefields...]
 		fields := strings.Split(scanner.Text(), ":")
-		if len(fields) < 3 || len(fields[0]) < 1 || len(fields[2]) < 2 {
+		if len(fields) < 3 || len(fields[0]) < 1 || len(fields[2]) < 3 {
 			continue
-		} else if fields[0][0] == '#' || fields[2][0] != '*' {
+		} else if fields[0][0] == '#' || fields[2][0] != '*' || fields[2][1] != '.' {
 			continue
 		}
 

src/mime/type_unix_test.go

@@ -27,6 +27,8 @@ func TestTypeByExtensionUNIX(t *testing.T) {
 		".t3":  "document/test",
 		".t4":  "example/test",
 		".png": "image/png",
+		",v":   "",
+		"~":    "",
 	}
 
 	for ext, want := range typeTests {