Update version handling.

* macros/neon.m4 (NE_MINIMUM_VERSION): New macro.
  (NE_REQUIRE_VERSIONS): Rejig to use NE_MINIMUM_VERSION. The first
  version given in minor releases is used as the minimum, all
  others now ignored.

* test/util-tests.c (versioning): Update versioning to assume 1.0 is
  maintains backwards-compat to 0.27.

* README.md: Note use of semver.

README.md

@@ -1,5 +1,4 @@
 
-[![Travis CI Build Status](https://travis-ci.com/notroj/neon.svg?branch=master)](https://travis-ci.com/github/notroj/neon)
 [![Build and test](https://github.com/notroj/neon/actions/workflows/ci.yml/badge.svg)](https://github.com/notroj/neon/actions/workflows/ci.yml)
 
 # neon
@@ -9,7 +8,8 @@ _neon_ is an HTTP and WebDAV client library, with a C language API.
 GitHub: https://github.com/notroj/neon | Web: https://notroj.github.io/neon/
 
 The neon API and ABI are stable and maintain backwards compatibility
-since 0.27 through to current releases.
+since 0.27 through to 1.0.0. From neon 1.0.0 onwards, semantic
+versioning will be used. https://semver.org/
 
 Features:
 
@@ -43,7 +43,7 @@ The autoconf macros in the "macros" directory are under a less
 restrictive license, see each file for details.
 
 ~~~
-neon is Copyright (C) 1999-2023 Joe Orton
+neon is Copyright (C) 1999-2024 Joe Orton
 Portions are:
 Copyright (C) Aleix Conchillo Flaque
 Copyright (C) Arfrever Frehtes Taifersar Arahesis

macros/neon.m4

@@ -157,14 +157,26 @@ else
 fi
 ])
 
-dnl Define the minimum required versions, usage:
-dnl   NE_REQUIRE_VERSIONS([major-version], [minor-versions])
-dnl e.g.
-dnl   NE_REQUIRE_VERSIONS([0], [24 25])
-dnl to require neon 0.24.x or neon 0.25.x.
-AC_DEFUN([NE_REQUIRE_VERSIONS], [
+dnl Define the minimum required version, usage:
+dnl   NE_MINIMUM_VERSION([major-version], [minor-version])
+dnl If a major-version of 0 is used, neon 1.x will be allowed
+dnl as backward compatible. FOr example:
+dnl   NE_MINIMUM_VERSION([0], [27])
+dnl require neon 0.27.x or later or any 1.x
+AC_DEFUN([NE_MINIMUM_VERSION], [
 m4_define([ne_require_major], [$1])
+# ## ne_require_major $1
 m4_define([ne_require_minor], [$2])
+# ## ne_require_minor $2
+])
+
+
+dnl Deprecated.
+AC_DEFUN([NE_REQUIRE_VERSIONS], [
+# Extract the first minor version from the list:
+NE_MINIMUM_VERSIONS([$1],m4_bregexp($2,[\([0-9]*\)\ .*],[\1]))
+m4_warn([obsolete], [The `NE_REQUIRE_VERSIONS` macro is obsolete.
+Update to use `NE_MINIMUM_VERSION`])
 ])
 
 dnl Check that the external library found in a given location
@@ -189,26 +201,32 @@ m4_ifdef([ne_require_major], [
         [AC_LANG_PROGRAM([[#include <ne_utils.h>]], [[ne_version_match(0, 0);]])],
 	[ne_cv_lib_neon=yes], [ne_cv_lib_neon=no])])
     if test "$ne_cv_lib_neon" = "yes"; then
+       ne_libmajor=`echo $ne_libver | sed 's/\..*//g'`
+       ne_libminor=`echo $ne_libver | sed 's/.*\.\([[0-9]]*\)\..*/\1/g'`
        ne_cv_lib_neonver=no
-       for v in ne_require_minor; do
-          case $ne_libver in
-          ne_require_major.$v.*) ne_cv_lib_neonver=yes ;;
-          esac
-       done
+       AC_MSG_NOTICE([found neon library version ${ne_libmajor}.${ne_libminor}.x, required ne_require_major[.]ne_require_minor[.x]])
+       # neon 1.x maintains backwards compat to neon 0.27.x
+       if test ne_require_major -eq 0 -a ne_require_minor -ge 27 \
+          -a $ne_libmajor = 1; then
+          ne_cv_lib_neonver=yes
+       elif test $ne_libmajor -eq ne_require_major \
+            -a $ne_libminor -ge ne_require_minor; then
+          ne_cv_lib_neonver=yes
+       fi
     fi
     ne_goodver=$ne_cv_lib_neonver
     LIBS=$ne_save_LIBS
     CFLAGS=$ne_save_CFLAGS
 ], [
-   # NE_REQUIRE_VERSIONS not used; presume all versions OK!
+    dnl NE_REQUIRE_VERSIONS/NE_MINIMUM_VERSION not used; anything goes.
     ne_goodver=yes
 ])
 
 if test "$ne_goodver" = "yes"; then
     AC_MSG_NOTICE([using neon library $ne_libver])
     $1
 else
-    AC_MSG_NOTICE([incompatible neon library version $ne_libver: wanted ne_require_major.ne_require_minor])
+    AC_MSG_NOTICE([incompatible neon library version $ne_libver: minimum required ne_require_major.ne_require_minor])
     $2
 fi])
 

test/util-tests.c

@@ -288,18 +288,22 @@ static int versioning(void)
     GOOD(NE_VERSION_MAJOR, NE_VERSION_MINOR, "current version");
     BAD(NE_VERSION_MAJOR + 1, 0, "later major");
     BAD(NE_VERSION_MAJOR, NE_VERSION_MINOR + 1, "later minor");
-#if NE_VERSION_MAJOR > 0
+
+#if NE_VERSION_MAJOR > 1
     BAD(NE_VERSION_MAJOR - 1, 0, "earlier major");
 #if NE_VERSION_MINOR > 0
     GOOD(NE_VERSION_MAJOR, NE_VERSION_MINOR - 1, "earlier minor");
 #endif /* NE_VERSION_MINOR > 0 */
-#else /* where NE_VERSION_MAJOR == 0 */
-    BAD(0, 26, "earlier minor for 0.x");
+
+#else /* where NE_VERSION_MAJOR < 2; note that 0.28 thru 1.0 maintain
+       * backwards compatibility to 0.27 */
+    BAD(0, 26, "minor version before 0.27");
     GOOD(0, 27, "current version back-compat to 0.27");
     GOOD(0, 28, "current version back-compat to 0.28");
     GOOD(0, 29, "current version back-compat to 0.29");
     GOOD(0, 30, "current version back-compat to 0.30");
 #endif
+
     return OK;
 }