From 00388c4e0f252f29426416b33d2f4d13c1dcdbb6 Mon Sep 17 00:00:00 2001
From: Dana Robinson <derobins@hdfgroup.org>
Date: Wed, 19 Aug 2020 12:04:34 -0700
Subject: Disables memory sanity checks in Autotools debug builds

** ONLY FOR THIS RELEASE BRANCH **
---
 configure.ac             |  7 ++-----
 release_docs/RELEASE.txt | 17 +++++++++++++++++
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/configure.ac b/configure.ac
index c2f5570..25ba5c0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2555,7 +2555,8 @@ AC_ARG_ENABLE([memory-alloc-sanity-check],
                               more memory use and somewhat slower allocation.
                               This option is orthogonal to the
                               --enable-using-memchecker option.
-                               [default=yes if debug build, otherwise no]
+                               [default=yes if debug build in a development
+                                branch, otherwise no]
                               ])],
               [MEMORYALLOCSANITYCHECK=$enableval])
 
@@ -2565,11 +2566,7 @@ AC_SUBST([MEMORYALLOCSANITYCHECK])
 
 ## Set default
 if test "X-$MEMORYALLOCSANITYCHECK" = X- ; then
-  if test "X-$BUILD_MODE" = "X-debug" ; then
-    MEMORYALLOCSANITYCHECK=yes
-  else
     MEMORYALLOCSANITYCHECK=no
-  fi
 fi
 
 case "X-$MEMORYALLOCSANITYCHECK" in
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index 719b018..d235a66 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -47,6 +47,23 @@ New Features
 
     Configuration:
     -------------
+    - Disable memory sanity checks in the Autotools in release branches
+
+      The library can be configured to use internal memory sanity checking,
+      which replaces C API calls like malloc(3) and free(3) with our own calls
+      which add things like heap canaries. These canaries can cause problems
+      when external filter plugins reallocate canary-marked buffers.
+
+      For this reason, the default will be to not use the memory allocation
+      sanity check feature in release branches (e.g., hdf5_1_10_7).
+      Debug builds in development branches (e.g., develop, hdf5_1_10) will
+      still use them by default.
+
+      This change only affects Autotools debug builds. Non-debug autotools
+      builds and all CMake builds do not enable this feature by default.
+
+      (DER - 2020/08/19)
+
     - Add file locking configure and CMake options
 
       HDF5 1.10.0 introduced a file locking scheme, primarily to help
-- 
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