node: manually implement Debug
authorAugie Fackler <augie@google.com>
Thu, 05 May 2022 14:47:26 -0400
changeset 49175 34decbaf4da3
parent 49174 3f86ee422095
child 49176 3cd3aaba5b03
node: manually implement Debug I got too irritated today with the default Debug implementation of hg::revlog::Node while playing with a new parser. This isn't quite what I wanted, but it wasn't much code and it at least gives you output that's easy to visually compare to a node.hex()ed identifier from the Python side of things. Sadly, this doesn't influence the output in lldb or the VSCode debugger extension that uses lldb under the covers, but it at least means debug prints are a little more useful. Differential Revision: https://phab.mercurial-scm.org/D12608
rust/hg-core/src/revlog/node.rs
--- a/rust/hg-core/src/revlog/node.rs	Thu May 05 15:38:29 2022 +0100
+++ b/rust/hg-core/src/revlog/node.rs	Thu May 05 14:47:26 2022 -0400
@@ -53,12 +53,21 @@
 /// the size or return an error at runtime.
 ///
 /// [`nybbles_len`]: #method.nybbles_len
-#[derive(Copy, Clone, Debug, PartialEq, BytesCast, derive_more::From)]
+#[derive(Copy, Clone, PartialEq, BytesCast, derive_more::From)]
 #[repr(transparent)]
 pub struct Node {
     data: NodeData,
 }
 
+impl fmt::Debug for Node {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let n = format!("{:x?}", self.data);
+        // We're using debug_tuple because it makes the output a little
+        // more compact without losing data.
+        f.debug_tuple("Node").field(&n).finish()
+    }
+}
+
 /// The node value for NULL_REVISION
 pub const NULL_NODE: Node = Node {
     data: [0; NODE_BYTES_LENGTH],