Skip scanning for surrogates when known invalid

thaliaarchi · thaliaarchi · commit 44715008c095 · 2025-02-07T11:54:02.000-08:00
diff --git a/library/std/src/sys_common/wtf8.rs b/library/std/src/sys_common/wtf8.rs
@@ -387,7 +387,7 @@ impl Wtf8Buf {
             _ => {
                 // If we'll be pushing a string containing a surrogate, we may
                 // no longer have UTF-8.
-                if other.next_surrogate(0).is_some() {
+                if self.is_known_utf8 && other.next_surrogate(0).is_some() {
                     self.is_known_utf8 = false;
                 }
 

Original file line number	Diff line number	Diff line change
`@@ -387,7 +387,7 @@ impl Wtf8Buf {`
`387`	`387`	`_ => {`
`388`	`388`	`// If we'll be pushing a string containing a surrogate, we may`
`389`	`389`	`// no longer have UTF-8.`
`390`		`- if other.next_surrogate(0).is_some() {`
	`390`	`+ if self.is_known_utf8 && other.next_surrogate(0).is_some() {`
`391`	`391`	`self.is_known_utf8 = false;`
`392`	`392`	`}`
`393`	`393`