Fix reading PEM from slices without trailing newline

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rustls-pki-types"
-version = "1.10.0"
+version = "1.10.1"
 edition = "2021"
 rust-version = "1.60"
 license = "MIT OR Apache-2.0"

src/pem.rs

@@ -203,6 +203,10 @@ fn from_slice(mut input: &[u8]) -> Result<Option<((SectionKind, Vec<u8>), &[u8])
             let (line, newline_plus_remainder) = input.split_at(index);
             input = &newline_plus_remainder[1..];
             Some(line)
+        } else if !input.is_empty() {
+            let next_line = input;
+            input = &[];
+            Some(next_line)
         } else {
             None
         };

tests/data/rsa-key-no-trailing-newline.pem

@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----

tests/pem.rs

@@ -74,6 +74,27 @@ fn any_private_key() {
     ));
 }
 
+#[test]
+fn no_trailing_newline() {
+    let data = include_bytes!("data/rsa-key-no-trailing-newline.pem");
+    assert_eq!(
+        PrivatePkcs8KeyDer::pem_slice_iter(data)
+            .collect::<Result<Vec<_>, _>>()
+            .unwrap()
+            .len(),
+        1
+    );
+
+    assert_eq!(
+        PrivatePkcs8KeyDer::pem_file_iter("tests/data/rsa-key-no-trailing-newline.pem")
+            .unwrap()
+            .collect::<Result<Vec<_>, _>>()
+            .unwrap()
+            .len(),
+        1
+    );
+}
+
 #[test]
 fn certificates() {
     let data = include_bytes!("data/zen.pem");