Properly update the binlog linked list pointers.

Code in this file assumes that newest_binlog is always correct, so when
there is no binlog at all, we must set newest_binlog to NULL.

Closes gh-44.

binlog.c

@@ -111,6 +111,10 @@ binlog_remove_oldest()
 
     oldest_binlog = b->next;
 
+    if (newest_binlog == b) {
+        newest_binlog = b->next; /* == 0 */
+    }
+
     unlink(b->path);
     free(b);
 }
@@ -778,7 +782,6 @@ binlog_init(job binlog_jobs)
 
     }
 
-
     /* Set up for writing out new jobs */
     n = ensure_free_space(1);
     if (!n) return twarnx("error making first writable binlog");

sh-tests/binlog-empty-oom.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+
+. "$SRCDIR/sh-tests/common.functions"
+
+server=localhost
+tmpdir="$TMPDIR"
+size=601
+test -z "$tmpdir" && tmpdir=/tmp
+out1="${tmpdir}/bnch$$.1"
+logdir="${tmpdir}/bnch$$.d"
+nc="$SRCDIR/sh-tests/netcat.py"
+
+cleanup() {
+    killbeanstalkd
+    rm -rf "$logdir" "$out1"
+}
+
+catch() {
+    echo '' Interrupted
+    exit 3
+}
+
+trap cleanup EXIT
+trap catch HUP INT QUIT TERM
+
+if [ ! -x ./beanstalkd ]; then
+  echo "Executable ./beanstalkd not found; do you need to compile first?"
+  exit 2
+fi
+
+start_beanstalkd $logdir
+
+killbeanstalkd -9
+
+start_beanstalkd $logdir
+
+$nc $server $port <<EOF > "$out1"
+put 0 0 0 0
+
+quit
+EOF
+
+diff - "$out1" <<EOF
+INSERTED 1
+EOF
+