Merge 10.1 into 10.2

4 files changed, 15 insertions, 4 deletions

diff --git a/mysys/CMakeLists.txt b/mysys/CMakeLists.txt
index 26dbd953324..b3467639f0b 100644
--- a/mysys/CMakeLists.txt
+++ b/mysys/CMakeLists.txt
@@ -1,4 +1,5 @@
 # Copyright (c) 2006, 2014, Oracle and/or its affiliates
+# Copyright (c) 2009, 2018, MariaDB Corporation
 # 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/mysys/mf_iocache.c b/mysys/mf_iocache.c
index 673f9762a86..e6d974a00d1 100644
--- a/mysys/mf_iocache.c
+++ b/mysys/mf_iocache.c
@@ -640,7 +640,7 @@ int _my_b_write(IO_CACHE *info, const uchar *Buffer, size_t Count)
 
 int _my_b_cache_read(IO_CACHE *info, uchar *Buffer, size_t Count)
 {
-  size_t length, diff_length, left_length= 0, max_length;
+  size_t length= 0, diff_length, left_length= 0, max_length;
   my_off_t pos_in_file;
   DBUG_ENTER("_my_b_cache_read");
 
@@ -756,7 +756,10 @@ int _my_b_cache_read(IO_CACHE *info, uchar *Buffer, size_t Count)
     else
     {
       info->error= 0;
-      DBUG_RETURN(0);                           /* EOF */
+      if (length == 0)                            /* nothing was read */
+        DBUG_RETURN(0);                           /* EOF */
+
+      length= 0;                       /* non-zero size read was done */
     }
   }
   else 
diff --git a/mysys/mf_iocache2.c b/mysys/mf_iocache2.c
index 2499094037d..fa3b6e672d7 100644
--- a/mysys/mf_iocache2.c
+++ b/mysys/mf_iocache2.c
@@ -1,4 +1,5 @@
-/* Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
+/* Copyright (c) 2000, 2018, Oracle and/or its affiliates.
+   Copyright (c) 2009, 2018, MariaDB Corporation
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -491,4 +492,3 @@ process_flags:
 err:
   return (size_t) -1;
 }
-
diff --git a/mysys/ptr_cmp.c b/mysys/ptr_cmp.c
index 6d853a8db25..add92edd713 100644
--- a/mysys/ptr_cmp.c
+++ b/mysys/ptr_cmp.c
@@ -52,6 +52,11 @@ static int ptr_compare_0(size_t *compare_length, uchar **a, uchar **b);
 static int ptr_compare_1(size_t *compare_length, uchar **a, uchar **b);
 static int ptr_compare_2(size_t *compare_length, uchar **a, uchar **b);
 static int ptr_compare_3(size_t *compare_length, uchar **a, uchar **b);
+static int degenerate_compare_func(size_t *compare_length, uchar **a, uchar **b)
+{
+  DBUG_ASSERT(*compare_length == 0);
+  return 0;
+}
 #endif	/* __sun */
 
 	/* Get a pointer to a optimal byte-compare function for a given size */
@@ -64,6 +69,8 @@ qsort2_cmp get_ptr_compare (size_t size __attribute__((unused)))
 #else
 qsort2_cmp get_ptr_compare (size_t size)
 {
+  if (size == 0)
+    return (qsort2_cmp) degenerate_compare_func;
   if (size < 4)
     return (qsort2_cmp) ptr_compare;
   switch (size & 3) {