refactor: build the librrd argument list without the dummy slot

.github/workflows/ci.yml

@@ -13,10 +13,16 @@ jobs:
   build:
     name: PHP ${{ matrix.php }}
     runs-on: ubuntu-latest
+    continue-on-error: ${{ matrix.experimental || false }}
     strategy:
       fail-fast: false
       matrix:
         php: ['8.1', '8.2', '8.3', '8.4', '8.5']
+        include:
+          # nightly build of php-src master; allowed to fail so an unrelated
+          # upstream break does not gate pull requests
+          - php: '8.6'
+            experimental: true
 
     steps:
       - name: Checkout
@@ -25,7 +31,7 @@ jobs:
       - name: Install librrd
         run: |
           sudo apt-get update
-          sudo apt-get install -y librrd-dev pkg-config
+          sudo apt-get install -y librrd-dev pkg-config rrdtool
 
       - name: Setup PHP
         uses: shivammathur/setup-php@f3e473d116dcccaddc5834248c87452386958240 # v2.37.2
@@ -40,6 +46,9 @@ jobs:
           ./configure --with-rrd
           make -j"$(nproc)"
 
+      - name: Generate test fixtures
+        run: make -C tests/data all
+
       - name: Test
         run: make test
         env:

.gitignore

@@ -29,3 +29,19 @@ modules
 run-tests.php
 tmp-php.ini
 tests/rrdtool-bin.inc
+*.dep
+configure.ac
+tests/*.diff
+tests/*.exp
+tests/*.log
+tests/*.out
+tests/*.php
+tests/*.sh
+tests/*.txt
+tests/*.png
+tests/*.rrd
+tests/data/*.png
+tests/data/*.rrd
+tests/data/*.txt
+tests/data/*.xml
+tests/data/Makefile

config.m4

@@ -30,6 +30,20 @@ if test "$PHP_RRD" != "no"; then
     AC_MSG_ERROR(pkgconfig and librrd in version >= 1.3.0 must be installed)
   fi
 
+  dnl librrd took char ** for argv before 1.9 and const char ** from 1.9 on
+  AC_MSG_CHECKING(whether librrd takes const char ** argv)
+  rrd_save_CFLAGS="$CFLAGS"
+  CFLAGS="$CFLAGS $LIBRRD_CFLAGS -Werror"
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+    [[#include <rrd.h>]],
+    [[const char *argv[2] = { "create", 0 }; rrd_create(1, argv);]])],
+    [
+      AC_MSG_RESULT(yes)
+      AC_DEFINE(HAVE_RRD_CONST_ARGV, 1, [librrd takes const char ** argv])
+    ],
+    [AC_MSG_RESULT(no)])
+  CFLAGS="$rrd_save_CFLAGS"
+
   dnl rrd_lastupdate_r available in 1.4.0+
   AC_CHECK_LIB([rrd], [rrd_lastupdate_r],
   [ 

php_rrd.h

@@ -24,6 +24,13 @@ extern zend_module_entry rrd_module_entry;
 # define zend_parse_parameters_none() zend_parse_parameters(ZEND_NUM_ARGS(), "")
 #endif 
 
+/* librrd took char ** for argv before 1.9 and const char ** from 1.9 on */
+#ifdef HAVE_RRD_CONST_ARGV
+# define RRD_ARGV(argv) ((const char **)(argv))
+#else
+# define RRD_ARGV(argv) (argv)
+#endif
+
 typedef struct _rrd_args {
 	int count;
 	char **args;