Panic when advance_slices()'ing too far.

m-ou-se · m-ou-se · commit a23e7513fa53 · 2022-03-11T17:29:53.000+01:00
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
@@ -1155,7 +1155,9 @@ impl<'a> IoSliceMut<'a> {
         }
 
         *bufs = &mut replace(bufs, &mut [])[remove..];
-        if !bufs.is_empty() {
+        if bufs.is_empty() {
+            assert!(n == accumulated_len, "advancing io slices beyond their length");
+        } else {
             bufs[0].advance(n - accumulated_len)
         }
     }
@@ -1289,7 +1291,9 @@ impl<'a> IoSlice<'a> {
         }
 
         *bufs = &mut replace(bufs, &mut [])[remove..];
-        if !bufs.is_empty() {
+        if bufs.is_empty() {
+            assert!(n == accumulated_len, "advancing io slices beyond their length");
+        } else {
             bufs[0].advance(n - accumulated_len)
         }
     }

Original file line number	Diff line number	Diff line change
`@@ -1155,7 +1155,9 @@ impl<'a> IoSliceMut<'a> {`
`1155`	`1155`	`}`
`1156`	`1156`
`1157`	`1157`	`*bufs = &mut replace(bufs, &mut [])[remove..];`
`1158`		`- if !bufs.is_empty() {`
	`1158`	`+ if bufs.is_empty() {`
	`1159`	`+ assert!(n == accumulated_len, "advancing io slices beyond their length");`
	`1160`	`+ } else {`
`1159`	`1161`	`bufs[0].advance(n - accumulated_len)`
`1160`	`1162`	`}`
`1161`	`1163`	`}`
`@@ -1289,7 +1291,9 @@ impl<'a> IoSlice<'a> {`
`1289`	`1291`	`}`
`1290`	`1292`
`1291`	`1293`	`*bufs = &mut replace(bufs, &mut [])[remove..];`
`1292`		`- if !bufs.is_empty() {`
	`1294`	`+ if bufs.is_empty() {`
	`1295`	`+ assert!(n == accumulated_len, "advancing io slices beyond their length");`
	`1296`	`+ } else {`
`1293`	`1297`	`bufs[0].advance(n - accumulated_len)`
`1294`	`1298`	`}`
`1295`	`1299`	`}`