From 5422e3cfb7ffc50b147b4662d6f596cd61533754 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@redhat.com>
Date: Fri, 26 Apr 2019 01:40:00 +0200
Subject: [PATCH] bpo-36722: Debug build loads libraries built in release mode
 (GH-12952)

In debug build, import now also looks for C extensions compiled in
release mode and for C extensions compiled in the stable ABI.
---
 .../2019-04-25-21-02-40.bpo-36722.8NApVM.rst         |  2 ++
 Python/dynload_shlib.c                               |  5 +++--
 configure                                            | 12 ++++++++++++
 configure.ac                                         |  8 ++++++++
 pyconfig.h.in                                        |  4 ++++
 5 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2019-04-25-21-02-40.bpo-36722.8NApVM.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-04-25-21-02-40.bpo-36722.8NApVM.rst b/Misc/NEWS.d/next/Core and Builtins/2019-04-25-21-02-40.bpo-36722.8NApVM.rst
new file mode 100644
index 0000000000..210a7e0525
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2019-04-25-21-02-40.bpo-36722.8NApVM.rst	
@@ -0,0 +1,2 @@
+In debug build, import now also looks for C extensions compiled in release
+mode and for C extensions compiled in the stable ABI.
diff --git a/Python/dynload_shlib.c b/Python/dynload_shlib.c
index e5bddaab6c..c51f97abd2 100644
--- a/Python/dynload_shlib.c
+++ b/Python/dynload_shlib.c
@@ -38,9 +38,10 @@ const char *_PyImport_DynLoadFiletab[] = {
     ".dll",
 #else  /* !__CYGWIN__ */
     "." SOABI ".so",
-#ifndef Py_DEBUG
+#ifdef ALT_SOABI
+    "." ALT_SOABI ".so",
+#endif
     ".abi" PYTHON_ABI_STRING ".so",
-#endif /* ! Py_DEBUG */
     ".so",
 #endif  /* __CYGWIN__ */
     NULL,
diff --git a/configure b/configure
index b02d17c053..b2775cf040 100755
--- a/configure
+++ b/configure
@@ -632,6 +632,7 @@ THREADHEADERS
 LIBPL
 PY_ENABLE_SHARED
 EXT_SUFFIX
+ALT_SOABI
 SOABI
 LIBC
 LIBM
@@ -15127,6 +15128,17 @@ SOABI='cpython-'`echo $VERSION | tr -d .`${ABIFLAGS}${PLATFORM_TRIPLET:+-$PLATFO
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $SOABI" >&5
 $as_echo "$SOABI" >&6; }
 
+if test "$Py_DEBUG" = 'true'; then
+  # Similar to SOABI but remove "d" flag from ABIFLAGS
+
+  ALT_SOABI='cpython-'`echo $VERSION | tr -d .``echo $ABIFLAGS | tr -d d`${PLATFORM_TRIPLET:+-$PLATFORM_TRIPLET}
+
+cat >>confdefs.h <<_ACEOF
+#define ALT_SOABI "${ALT_SOABI}"
+_ACEOF
+
+fi
+
 
 case $ac_sys_system in
     Linux*|GNU*|Darwin|VxWorks)
diff --git a/configure.ac b/configure.ac
index 65d3f8e691..312758788e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4627,6 +4627,14 @@ AC_MSG_CHECKING(SOABI)
 SOABI='cpython-'`echo $VERSION | tr -d .`${ABIFLAGS}${PLATFORM_TRIPLET:+-$PLATFORM_TRIPLET}
 AC_MSG_RESULT($SOABI)
 
+if test "$Py_DEBUG" = 'true'; then
+  # Similar to SOABI but remove "d" flag from ABIFLAGS
+  AC_SUBST(ALT_SOABI)
+  ALT_SOABI='cpython-'`echo $VERSION | tr -d .``echo $ABIFLAGS | tr -d d`${PLATFORM_TRIPLET:+-$PLATFORM_TRIPLET}
+  AC_DEFINE_UNQUOTED(ALT_SOABI, "${ALT_SOABI}",
+            [Alternative SOABI used in debug build to load C extensions built in release mode])
+fi
+
 AC_SUBST(EXT_SUFFIX)
 case $ac_sys_system in
     Linux*|GNU*|Darwin|VxWorks)
diff --git a/pyconfig.h.in b/pyconfig.h.in
index 562c027113..4b77961472 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -12,6 +12,10 @@
    support for AIX C++ shared extension modules. */
 #undef AIX_GENUINE_CPLUSPLUS
 
+/* Alternative SOABI used in debug build to load C extensions built in release
+   mode */
+#undef ALT_SOABI
+
 /* The Android API level. */
 #undef ANDROID_API_LEVEL
 
-- 
2.40.0