fix: match Go pretty JSON, JSONP format, and streaming compaction check

Pretty printing now activates for any non-empty ?pretty value (not just
?pretty=y). JSONP output drops trailing semicolon/newline to match Go.
StreamingBody now re-reads needle offset on compaction revision change.

seaweed-volume/src/server/handlers.rs

@@ -101,6 +101,15 @@ struct StreamingBody {
     /// For download throttling — released on drop.
     state: Option<Arc<VolumeServerState>>,
     tracked_bytes: i64,
+    /// Server state used to re-lookup needle offset if compaction occurs during streaming.
+    server_state: Arc<VolumeServerState>,
+    /// Volume ID for compaction-revision re-lookup.
+    volume_id: crate::storage::types::VolumeId,
+    /// Needle ID for compaction-revision re-lookup.
+    needle_id: crate::storage::types::NeedleId,
+    /// Compaction revision at the time of the initial read; if the volume's revision
+    /// changes between chunks, the needle may have moved and we must re-lookup its offset.
+    compaction_revision: u16,
 }
 
 impl http_body::Body for StreamingBody {
@@ -143,6 +152,36 @@ impl http_body::Body for StreamingBody {
                 return std::task::Poll::Ready(None);
             }
 
+            // Check if compaction has changed the needle's disk location (Go parity:
+            // readNeedleDataInto re-reads the needle offset when CompactionRevision changes).
+            let relookup_result = {
+                let store = self.server_state.store.read().unwrap();
+                if let Some((_, vol)) = store.find_volume(self.volume_id) {
+                    if vol.super_block.compaction_revision != self.compaction_revision {
+                        // Compaction occurred — re-lookup the needle's data offset
+                        Some(vol.re_lookup_needle_data_offset(self.needle_id))
+                    } else {
+                        None
+                    }
+                } else {
+                    None
+                }
+            };
+            if let Some(result) = relookup_result {
+                match result {
+                    Ok((new_offset, new_rev)) => {
+                        self.data_offset = new_offset;
+                        self.compaction_revision = new_rev;
+                    }
+                    Err(_) => {
+                        return std::task::Poll::Ready(Some(Err(std::io::Error::new(
+                            std::io::ErrorKind::NotFound,
+                            "needle not found after compaction",
+                        ))));
+                    }
+                }
+            }
+
             let chunk_len = std::cmp::min(self.chunk_size, total - self.pos);
             let file_offset = self.data_offset + self.pos as u64;
 
@@ -1038,6 +1077,10 @@ async fn get_or_head_handler_inner(
                 pending: None,
                 state: tracking_state,
                 tracked_bytes,
+                server_state: state.clone(),
+                volume_id: info.volume_id,
+                needle_id: info.needle_id,
+                compaction_revision: info.compaction_revision,
             };
 
             let body = Body::new(streaming);
@@ -2138,7 +2181,7 @@ pub async fn status_handler(
 
     let json_value = serde_json::Value::Object(m);
 
-    let is_pretty = params.pretty.as_deref() == Some("y");
+    let is_pretty = params.pretty.as_ref().is_some_and(|s| !s.is_empty());
     let json_body = if is_pretty {
         serde_json::to_string_pretty(&json_value).unwrap()
     } else {
@@ -2146,7 +2189,7 @@ pub async fn status_handler(
     };
 
     if let Some(ref cb) = params.callback {
-        let jsonp = format!("{}({});\n", cb, json_body);
+        let jsonp = format!("{}({})", cb, json_body);
         Response::builder()
             .header(header::CONTENT_TYPE, "application/javascript")
             .body(Body::from(jsonp))
@@ -2427,7 +2470,7 @@ fn try_expand_chunk_manifest(
 // ============================================================================
 
 /// Return a JSON error response with optional query string for pretty/JSONP support.
-/// Supports `?pretty=y` for pretty-printed JSON and `?callback=fn` for JSONP,
+/// Supports `?pretty=<any non-empty value>` for pretty-printed JSON and `?callback=fn` for JSONP,
 /// matching Go's writeJsonError behavior.
 fn json_error_with_query(
     status: StatusCode,
@@ -2437,7 +2480,9 @@ fn json_error_with_query(
     let body = serde_json::json!({"error": msg.into()});
 
     let (is_pretty, callback) = if let Some(q) = query {
-        let pretty = q.split('&').any(|p| p == "pretty=y");
+        let pretty = q.split('&').any(|p| {
+            p.starts_with("pretty=") && p.len() > "pretty=".len()
+        });
         let cb = q
             .split('&')
             .find_map(|p| p.strip_prefix("callback="))
@@ -2454,7 +2499,7 @@ fn json_error_with_query(
     };
 
     if let Some(cb) = callback {
-        let jsonp = format!("{}({});\n", cb, json_body);
+        let jsonp = format!("{}({})", cb, json_body);
         Response::builder()
             .status(status)
             .header(header::CONTENT_TYPE, "application/javascript")