auto merge of #10715 : alexcrichton/rust/fix-log-twice, r=huonw

It may mislead you into thinking tasks are spawning twice, when in fact they are
not.

1 files changed, 7 insertions, 5 deletions

diff --git a/src/libstd/logging.rs b/src/libstd/logging.rs
index 4af6d1d53be..1b540823f17 100644
--- a/src/libstd/logging.rs
+++ b/src/libstd/logging.rs
@@ -107,9 +107,10 @@ pub fn log(_level: u32, args: &fmt::Arguments) {
         let optional_task: Option<*mut Task> = Local::try_unsafe_borrow();
         match optional_task {
             Some(local) => {
+                // Lazily initialize the local task's logger
                 match (*local).logger {
                     // Use the available logger if we have one
-                    Some(ref mut logger) => return logger.log(args),
+                    Some(ref mut logger) => { logger.log(args); }
                     None => {
                         let mut logger = StdErrLogger::new();
                         logger.log(args);
@@ -117,10 +118,11 @@ pub fn log(_level: u32, args: &fmt::Arguments) {
                     }
                 }
             }
-            None => {}
+            // If there's no local task, then always log to stderr
+            None => {
+                let mut logger = StdErrLogger::new();
+                logger.log(args);
+            }
         }
-        // There is no logger anywhere, just write to stderr
-        let mut logger = StdErrLogger::new();
-        logger.log(args);
     }
 }