chore: print parent of retrace chain root during pre_open

The previous behavior was to print the parent of the new span, leading
to a parent being printed twice if the parent was also included in the
retrace chain.

Author: ten3roberts

examples/concurrent_eager.stdout

@@ -1,19 +1,15 @@
 1:main┐concurrent_eager::spawn_fut key="a"
 1:main┐concurrent_eager::spawn_fut key="b"
 1:main┐concurrent_eager::spawn_fut key="a"
-1:main├─┐concurrent_eager::spawn_fut key="a"
-1:main│ └─┐concurrent_eager::a 
+1:main├───┐concurrent_eager::a 
 1:main┐concurrent_eager::spawn_fut key="b"
-1:main├─┐concurrent_eager::spawn_fut key="b"
-1:main│ └─┐concurrent_eager::b 
+1:main├───┐concurrent_eager::b 
 1:main┐concurrent_eager::spawn_fut key="a"
-1:main├─┐concurrent_eager::spawn_fut key="a"
-1:main│ └─┐concurrent_eager::a 
+1:main├───┐concurrent_eager::a 
 1:main│   ├───  Xms INFO concurrent_eager a
 1:main├───┘
 1:main┐concurrent_eager::spawn_fut key="b"
-1:main├─┐concurrent_eager::spawn_fut key="b"
-1:main│ └─┐concurrent_eager::b 
+1:main├───┐concurrent_eager::b 
 1:main│   ├───  Xms INFO concurrent_eager b
 1:main├───┘
 1:main┘

examples/concurrent_verbose.stdout

@@ -1,21 +1,24 @@
 1:main┐concurrent_verbose::hierarchical-example version=0.1
-1:main├─┐concurrent_verbose::hierarchical-example version=0.1
-1:main│ └─┐concurrent_verbose::server host="localhost", port=8080
+1:main├───┐concurrent_verbose::server host="localhost", port=8080
 1:main│   ├───  Xms INFO concurrent_verbose starting
 1:main│   ├───  Xs  INFO concurrent_verbose listening
 1:main│   ├───  Xs  DEBUG concurrent_verbose starting countdowns
-1:main│   ├───┐concurrent_verbose::countdowns 
-1:main│   │   ├─┐concurrent_verbose::countdowns 
-1:main│   │   │ └─┐concurrent_verbose::countdown_a 
+1:main│   ├─┐concurrent_verbose::server host="localhost", port=8080
+1:main│   │ └─┐concurrent_verbose::countdowns 
+1:main│   │   ├───┐concurrent_verbose::countdown_a 
 1:main│   │   │   ├───  Xms DEBUG concurrent_verbose polling countdown, label="a", count=3
-1:main│   │   ├───┐concurrent_verbose::countdown_b 
+1:main│   │   ├─┐concurrent_verbose::countdowns 
+1:main│   │   │ └─┐concurrent_verbose::countdown_b 
 1:main│   │   │   ├───  Xms DEBUG concurrent_verbose polling countdown, label="b", count=5
 1:main│   │   │   ├───  Xms DEBUG concurrent_verbose polling countdown, label="b", count=4
-1:main│   │   ├───┐concurrent_verbose::countdown_a 
+1:main│   │   ├─┐concurrent_verbose::countdowns 
+1:main│   │   │ └─┐concurrent_verbose::countdown_a 
 1:main│   │   │   ├───  Xms DEBUG concurrent_verbose polling countdown, label="a", count=2
-1:main│   ├───┐concurrent_verbose::conn peer_addr="82.9.9.9", port=42381
+1:main│   ├─┐concurrent_verbose::server host="localhost", port=8080
+1:main│   │ └─┐concurrent_verbose::conn peer_addr="82.9.9.9", port=42381
 1:main│   │   ├───  Xms WARN concurrent_verbose peer1 warning
-1:main│   ├───┐concurrent_verbose::countdowns 
+1:main│   ├─┐concurrent_verbose::server host="localhost", port=8080
+1:main│   │ └─┐concurrent_verbose::countdowns 
 1:main│   │   ├───  Xms INFO concurrent_verbose finished polling countdowns
 1:main│   │   │ ┌─┘concurrent_verbose::countdown_b 
 1:main│   │   ├─┘concurrent_verbose::countdowns 

examples/deferred.stdout

@@ -1,32 +1,35 @@
 -> This prints before the span open message
 1:main┐open: deferred::hierarchical-example version=0.1
-1:main├┐pre_open: deferred::hierarchical-example version=0.1
-1:main│└┐open(v): deferred::server host="localhost", port=8080
+1:main├─┐open: deferred::server host="localhost", port=8080
 1:main│ ├─  Xms INFO deferred starting
 1:main│ ├─  Xs  INFO deferred listening
 -> Deferring two levels of spans
-1:main│ ├─┐open: deferred::connections 
-1:main│ │ ├┐pre_open: deferred::connections 
-1:main│ │ │└┐open(v): deferred::conn peer_addr="82.9.9.9", port=42381
+1:main│ ├┐pre_open: deferred::server host="localhost", port=8080
+1:main│ │└┐open(v): deferred::connections 
+1:main│ │ ├─┐open: deferred::conn peer_addr="82.9.9.9", port=42381
 1:main│ │ │ ├─  Xms DEBUG deferred connected, peer="peer1"
 1:main│ │ │ ├─  Xms DEBUG deferred message received, length=2
 1:main│ │ │┌┘close(v): deferred::conn peer_addr="82.9.9.9", port=42381
 1:main│ │ ├┘post_close: deferred::connections 
-1:main│ │ ├─┐open: deferred::conn peer_addr="8.8.8.8", port=18230
+1:main│ │ ├┐pre_open: deferred::connections 
+1:main│ │ │└┐open(v): deferred::conn peer_addr="8.8.8.8", port=18230
 1:main│ │ │ ├─  Xms DEBUG deferred connected, peer="peer3"
 1:main│ │ │┌┘close(v): deferred::conn peer_addr="8.8.8.8", port=18230
 1:main│ │ ├┘post_close: deferred::connections 
-1:main│ │ ├─┐open: deferred::foomp 42 <- format string, normal_var=43
+1:main│ │ ├┐pre_open: deferred::connections 
+1:main│ │ │└┐open(v): deferred::foomp 42 <- format string, normal_var=43
 1:main│ │ │ ├─  Xms ERROR deferred hello
 1:main│ │ │┌┘close(v): deferred::foomp 42 <- format string, normal_var=43
 1:main│ │ ├┘post_close: deferred::connections 
-1:main│ │ ├─┐open: deferred::conn peer_addr="82.9.9.9", port=42381
+1:main│ │ ├┐pre_open: deferred::connections 
+1:main│ │ │└┐open(v): deferred::conn peer_addr="82.9.9.9", port=42381
 1:main│ │ │ ├─  Xms WARN deferred weak encryption requested, algo="xor"
 1:main│ │ │ ├─  Xms DEBUG deferred response sent, length=8
 1:main│ │ │ ├─  Xms DEBUG deferred disconnected
 1:main│ │ │┌┘close(v): deferred::conn peer_addr="82.9.9.9", port=42381
 1:main│ │ ├┘post_close: deferred::connections 
-1:main│ │ ├─┐open: deferred::conn peer_addr="8.8.8.8", port=18230
+1:main│ │ ├┐pre_open: deferred::connections 
+1:main│ │ │└┐open(v): deferred::conn peer_addr="8.8.8.8", port=18230
 1:main│ │ │ ├─  Xms DEBUG deferred message received, length=5
 1:main│ │ │ ├─  Xms DEBUG deferred response sent, length=8
 1:main│ │ │ ├─  Xms DEBUG deferred disconnected

src/lib.rs

@@ -307,10 +307,11 @@ where
                     false
                 };
 
-                let verbose = i == 1 && pre_open && span.id() == new_span_id;
-                // Print the parent of the new span if `pre_open==true`
-                if verbose {
+                // Print the parent of the first span
+                let mut verbose = false;
+                if i == 0 && pre_open {
                     if let Some(span) = span.parent() {
+                        verbose = true;
                         self.write_span_info(&span, bufs, SpanMode::PreOpen);
                     }
                 }