Preserve input lineno when no mapping is available

Author: romtsn

src/cache/mod.rs

@@ -909,7 +909,8 @@ impl<'r, 'data> RemappedFrameIter<'r, 'data> {
                             class,
                             method,
                             file,
-                            line: 0,
+                            // Preserve input line if present when the mapping has no line info.
+                            line: frame.line,
                             parameters: frame.parameters,
                             method_synthesized: first_base.is_synthesized(),
                         });
@@ -945,7 +946,8 @@ impl<'r, 'data> RemappedFrameIter<'r, 'data> {
                         class,
                         method,
                         file,
-                        line: 0,
+                        // Preserve input line if present when the mapping has no line info.
+                        line: frame.line,
                         parameters: frame.parameters,
                         method_synthesized: first.is_synthesized(),
                     });
@@ -1005,6 +1007,26 @@ fn iterate_with_lines<'a>(
         if has_line_info && frame.line > 0 && member.endline == 0 {
             continue;
         }
+        // If the mapping entry has no line range, preserve the input line number (if any).
+        if member.endline == 0 {
+            let class = cache
+                .read_string(member.original_class_offset)
+                .unwrap_or(frame.class);
+
+            let method = cache.read_string(member.original_name_offset).ok()?;
+
+            // Synthesize from class name (input filename is not reliable)
+            let file = synthesize_source_file(class, outer_source_file).map(Cow::Owned);
+
+            return Some(StackFrame {
+                class,
+                method,
+                file,
+                line: frame.line,
+                parameters: frame.parameters,
+                method_synthesized: member.is_synthesized(),
+            });
+        }
         // skip any members which do not match our frames line
         if member.endline > 0
             && (frame.line < member.startline as usize || frame.line > member.endline as usize)
@@ -1080,7 +1102,8 @@ fn iterate_without_lines_preferring_base<'a>(
             class,
             method,
             file,
-            line: 0,
+            // Preserve input line if present when the mapping has no line info.
+            line: frame.line,
             parameters: frame.parameters,
             method_synthesized: member.is_synthesized(),
         });
@@ -1109,7 +1132,8 @@ fn iterate_without_lines<'a>(
         class,
         method,
         file,
-        line: 0,
+        // Preserve input line if present when the mapping has no line info.
+        line: frame.line,
         parameters: frame.parameters,
         method_synthesized: member.is_synthesized(),
     })

src/mapper.rs

@@ -224,7 +224,9 @@ fn map_member_without_lines<'a>(
         class,
         method: member.original,
         file,
-        line: 0,
+        // Preserve input line if present (e.g. "Unknown Source:7") when the mapping itself
+        // has no line information. This matches R8 retrace behavior.
+        line: frame.line,
         parameters: frame.parameters,
         method_synthesized: member.is_synthesized,
     }
@@ -272,6 +274,10 @@ fn iterate_with_lines<'a>(
         if has_line_info && frame.line > 0 && member.endline == 0 {
             continue;
         }
+        // If the mapping entry has no line range, preserve the input line number (if any).
+        if member.endline == 0 {
+            return Some(map_member_without_lines(frame, member));
+        }
         if let Some(mapped) = map_member_with_lines(frame, member) {
             return Some(mapped);
         }
@@ -596,7 +602,12 @@ impl<'s> ProguardMapper<'s> {
                 if has_line_info && member.endline == 0 {
                     continue;
                 }
-                if let Some(mapped) = map_member_with_lines(&frame, member) {
+                if member.endline == 0 {
+                    collected
+                        .frames
+                        .push(map_member_without_lines(&frame, member));
+                    collected.rewrite_rules.extend(member.rewrite_rules.iter());
+                } else if let Some(mapped) = map_member_with_lines(&frame, member) {
                     collected.frames.push(mapped);
                     collected.rewrite_rules.extend(member.rewrite_rules.iter());
                 }

tests/retrace.rs

@@ -71,7 +71,8 @@ fn test_remap_no_lines() {
     let mut mapped = mapper.remap_frame(&StackFrame::new("a", "b", 10));
     assert_eq!(
         mapped.next().unwrap(),
-        StackFrame::with_file("original.class.name", "originalMethodName", 0, "name.java")
+        // Preserve input line number when the mapping has no line information.
+        StackFrame::with_file("original.class.name", "originalMethodName", 10, "name.java")
     );
     assert_eq!(mapped.next(), None);
 }