gh-157354 : Honor disabled sanitizer configure options

Author: lpyu001

Misc/NEWS.d/next/Build/2026-09-12-15-33-26.gh-issue-157354.2hw6fe.rst

@@ -0,0 +1,3 @@
+Honor ``=no`` and ``--without-...`` for the AddressSanitizer,
+MemorySanitizer, UndefinedBehaviorSanitizer, and ThreadSanitizer configure
+options without adding sanitizer flags or changing the pymalloc setting.

configure

@@ -3519,14 +3519,14 @@ AC_MSG_CHECKING([for --with-address-sanitizer])
 AC_ARG_WITH([address_sanitizer],
             AS_HELP_STRING([--with-address-sanitizer],
                            [enable AddressSanitizer memory error detector, 'asan' (default is no)]),
-[
-AC_MSG_RESULT([$withval])
+[], [with_address_sanitizer=no])
+AC_MSG_RESULT([$with_address_sanitizer])
+AS_VAR_IF([with_address_sanitizer], [no], [], [
 BASECFLAGS="-fsanitize=address -fno-omit-frame-pointer $BASECFLAGS"
 LDFLAGS="-fsanitize=address $LDFLAGS"
 # ASan works by controlling memory allocation, our own malloc interferes.
 with_pymalloc="no"
-],
-[AC_MSG_RESULT([no])])
+])
 
 AC_MSG_CHECKING([for --with-memory-sanitizer])
 AC_ARG_WITH(
@@ -3535,16 +3535,16 @@ AC_ARG_WITH(
     [--with-memory-sanitizer],
     [enable MemorySanitizer allocation error detector, 'msan' (default is no)]
   )],
-[
-AC_MSG_RESULT([$withval])
+[], [with_memory_sanitizer=no])
+AC_MSG_RESULT([$with_memory_sanitizer])
+AS_VAR_IF([with_memory_sanitizer], [no], [], [
 AX_CHECK_COMPILE_FLAG([-fsanitize=memory],[
 BASECFLAGS="-fsanitize=memory -fsanitize-memory-track-origins=2 -fno-omit-frame-pointer $BASECFLAGS"
 LDFLAGS="-fsanitize=memory -fsanitize-memory-track-origins=2 $LDFLAGS"
 ],[AC_MSG_ERROR([The selected compiler doesn't support memory sanitizer])])
 # MSan works by controlling memory allocation, our own malloc interferes.
 with_pymalloc="no"
-],
-[AC_MSG_RESULT([no])])
+])
 
 AC_MSG_CHECKING([for --with-undefined-behavior-sanitizer])
 AC_ARG_WITH(
@@ -3553,15 +3553,14 @@ AC_ARG_WITH(
     [--with-undefined-behavior-sanitizer],
     [enable UndefinedBehaviorSanitizer undefined behaviour detector, 'ubsan' (default is no)]
   )],
-[
-AC_MSG_RESULT([$withval])
+[], [with_undefined_behavior_sanitizer=no])
+AC_MSG_RESULT([$with_undefined_behavior_sanitizer])
+AS_VAR_IF([with_undefined_behavior_sanitizer], [no], [
+with_ubsan="no"
+], [
 BASECFLAGS="-fsanitize=undefined $BASECFLAGS"
 LDFLAGS="-fsanitize=undefined $LDFLAGS"
 with_ubsan="yes"
-],
-[
-AC_MSG_RESULT([no])
-with_ubsan="no"
 ])
 
 AC_MSG_CHECKING([for --with-thread-sanitizer])
@@ -3571,15 +3570,14 @@ AC_ARG_WITH(
     [--with-thread-sanitizer],
     [enable ThreadSanitizer data race detector, 'tsan' (default is no)]
   )],
-[
-AC_MSG_RESULT([$withval])
+[], [with_thread_sanitizer=no])
+AC_MSG_RESULT([$with_thread_sanitizer])
+AS_VAR_IF([with_thread_sanitizer], [no], [
+with_tsan="no"
+], [
 BASECFLAGS="-fsanitize=thread $BASECFLAGS"
 LDFLAGS="-fsanitize=thread $LDFLAGS"
 with_tsan="yes"
-],
-[
-AC_MSG_RESULT([no])
-with_tsan="no"
 ])
 
 # Set info about shared libraries.