address review: cut only an over-long identifier; test with a filter that can't be read

crates/preflight/src/lib.rs

@@ -194,12 +194,11 @@ pub fn declared(doc: &Document) -> Declared {
                     .get(b"OutputConditionIdentifier")
                     .and_then(|v| {
                         doc.resolve(v).as_string().map(|s| {
-                            // An even cut keeps UTF-16 text whole code units.
-                            let n = s.bytes.len().min(MAX_IDENTIFIER_BYTES) & !1;
-                            if n == s.bytes.len() {
+                            if s.bytes.len() <= MAX_IDENTIFIER_BYTES {
                                 s.to_text()
                             } else {
-                                pdfcraft_cos::PdfString { bytes: s.bytes[..n].to_vec(), hex: s.hex }.to_text()
+                                // An even cut keeps UTF-16 text whole code units.
+                                pdfcraft_cos::PdfString { bytes: s.bytes[..MAX_IDENTIFIER_BYTES & !1].to_vec(), hex: s.hex }.to_text()
                             }
                         })
                     })

crates/preflight/src/tests.rs

@@ -541,7 +541,8 @@ fn convert_adds_no_srgb_intent_when_colour_could_not_all_be_read() {
             "<< /Type /Catalog /Pages 2 0 R >>",
             "<< /Type /Pages /Kids [3 0 R] /Count 1 /MediaBox [0 0 200 200] >>",
             "<< /Type /Page /Parent 2 0 R /Contents 4 0 R /Resources << >> >>",
-            "<< /Length 9 /Filter /FlateDecode >>\nstream\nnot flate\nendstream",
+            // A /Filter that isn't a name can't be decoded: the content isn't read.
+            "<< /Length 9 /Filter 5 >>\nstream\nnot flate\nendstream",
         ],
         "",
     );