[shepherd] 04/07: comm: Do not introduce empty lines in the log.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository shepherd.

commit e45820839e23a19a00347d3b8f88206243fb3eb0
Author: Ludovic Courtès <address@hidden>
Date:   Wed Sep 19 16:23:49 2018 +0200

    comm: Do not introduce empty lines in the log.
    
    Fixes a regression introduced in
    329cec8b6fcc57f945e748793470f573b2b449a3 whereby regular "has been
    started" etc. lines in the log would be followed by an empty line.
    
    * modules/shepherd/comm.scm (make-shepherd-output-port): Use
    'string-index' in a loop instead of 'string-split' to detect newlines in
    STR.
    * tests/basic.sh: Check for zero empty lines in $log.
---
 modules/shepherd/comm.scm | 21 +++++++++++++--------
 tests/basic.sh            |  5 +++++
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/modules/shepherd/comm.scm b/modules/shepherd/comm.scm
index 43110a7..c31bf02 100644
--- a/modules/shepherd/comm.scm
+++ b/modules/shepherd/comm.scm
@@ -308,18 +308,23 @@ available."
         ;; completed line.
         (if (not (string-index str #\newline))
             (set! buffer (cons str buffer))
-            (let* ((str   (string-concatenate-reverse (cons str buffer)))
-                   (lines (string-split str #\newline)))
+            (let ((str (string-concatenate-reverse (cons str buffer))))
               (define prefix
                 (strftime (%current-logfile-date-format)
                           (localtime (current-time))))
 
-              ;; Make exactly one 'display' call per line to make sure we
-              ;; don't create several entries for each line.
-              (for-each (lambda (line)
-                          (display (string-append prefix line "\n")
-                                   (log-output-port)))
-                        lines)
+              ;; Note: We want to render as many newlinew as present in STR,
+              ;; so neither 'string-split' nor 'string-tokenize' helps.
+              (let loop ((str str))
+                (let* ((index (string-index str #\newline))
+                       (line  (if index (string-take str (+ 1 index)) str)))
+                  (unless (string-null? str)
+                    ;; Make exactly one 'display' call per line to make sure we
+                    ;; don't create several entries for each line.
+                    (display (string-append prefix line) (log-output-port))
+                    (when index
+                      (loop (string-drop str (+ index 1)))))))
+
               (set! buffer '())))))
 
     ;; Flush output.
diff --git a/tests/basic.sh b/tests/basic.sh
index fc53aa7..cd4ade9 100644
--- a/tests/basic.sh
+++ b/tests/basic.sh
@@ -98,6 +98,11 @@ then false; else true; fi
 $herd enable test-2
 $herd start test-2
 
+# Make sure we didn't emit empty lines in the log (strip the timestamp that
+# prefixes each line.)
+test `wc -l < "$log"` -gt 0
+test `cut -c 21- < "$log" | grep "^$" | wc -l` -eq 0
+
 # Try a custom action; make sure we get all the lines, including the empty
 # lines (this was not the case in 0.4.0.)
 $herd doc test-2 action hi | grep "Say hi\."