zeek-config: Move ZEEK_VERSION* out of zeek-config.h

When bumping the VERSION file, everything that includes the auto-generated
zeek/zeek-config.h needs to rebuild and ccache usage is voided due the file
changing. Split the mutable version information into a new zeek-version.h
file to avoid this.

Further, do not include zeek-version.h within Plugin.h and avoid the reference
to ZEEK_VERSION_FUNCTION unless we're building an external plugin.

Closes #2776.

CMakeLists.txt

@@ -759,6 +759,9 @@ if ( NOT BINARY_PACKAGING_MODE )
 endif ()
 
 string(TOLOWER ${CMAKE_BUILD_TYPE} CMAKE_BUILD_TYPE_LOWER)
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/zeek-version.h.in
+               ${CMAKE_CURRENT_BINARY_DIR}/zeek-version.h)
+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/zeek-version.h DESTINATION include/zeek)
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/zeek-config.h.in
                ${CMAKE_CURRENT_BINARY_DIR}/zeek-config.h)
 include_directories(BEFORE ${CMAKE_CURRENT_BINARY_DIR})

NEWS

@@ -6,6 +6,25 @@ release. For an exhaustive list of changes, see the ``CHANGES`` file
 Zeek 6.0.0
 ==========
 
+Breaking Changes
+----------------
+
+- The zeek/zeek-config.h header does not provide the macros ZEEK_VERSION and
+  ZEEK_VERSION_NUMBER anymore when compiling builtin plugins. This may affect
+  external plugins included via the configure flag ``--include-plugins``
+  referencing these macros. A suggested update for these plugins is adding
+  the following snippet:
+
+	#if __has_include("zeek/zeek-version.h")
+	#include "zeek/zeek-version.h"
+	#endif
+
+  External plugins that are built out-of-tree, e.g. via ``zkg`` are not
+  affected by this change.
+
+  The main motivation is improved ccache effectiveness for speedier CI and
+  development builds whenever a VERSION bump happens.
+
 New Functionality
 -----------------
 

src/plugin/Plugin.h

@@ -2,8 +2,6 @@
 
 #pragma once
 
-#include "zeek/zeek-config.h"
-
 #include <functional>
 #include <list>
 #include <optional>
@@ -13,9 +11,15 @@
 #include "zeek/ZeekArgs.h"
 #include "zeek/logging/WriterBackend.h"
 
+// Avoid ccache busting of Plugin.h for internal plugins by
+// only including zeek/zeek-version.h if we're building an
+// external plugin.
+#if defined(ZEEK_PLUGIN_INTERNAL_BUILD) && ! ZEEK_PLUGIN_INTERNAL_BUILD
+#include "zeek/zeek-version.h"
 // Remove the BRO define in v6.1.
 #define BRO_PLUGIN_BRO_VERSION ZEEK_VERSION_FUNCTION
 #define ZEEK_PLUGIN_ZEEK_VERSION ZEEK_VERSION_FUNCTION
+#endif
 
 namespace zeek::threading
 	{
@@ -126,8 +130,13 @@ public:
 #endif
 	inline Configuration() __attribute__((always_inline))
 		{
+// Only bake in a ZEEK_PLUGIN_ZEEK_VERSION reference into external
+// plugins. The internal ones are in the same binary so the runtime
+// link check shouldn't be needed and we can avoid ccache busting.
+#if defined(ZEEK_PLUGIN_INTERNAL_BUILD) && ! ZEEK_PLUGIN_INTERNAL_BUILD
 		bro_version = ZEEK_PLUGIN_ZEEK_VERSION;
 		zeek_version = ZEEK_PLUGIN_ZEEK_VERSION;
+#endif
 		}
 #ifdef __GNUC__
 #pragma GCC diagnostic pop

src/version.c.in

@@ -1,5 +1,5 @@
 
-#include "zeek/zeek-config.h"
+#include "zeek/zeek-version.h"
 
 char version[] = "@VERSION@";
 

zeek-config.h.in

@@ -141,14 +141,6 @@
 /* Use the sqlite reader/writer. */
 #cmakedefine USE_SQLITE
 
-/* Version number of package */
-#define VERSION "@VERSION@"
-
-// Zeek version number.
-// This is the result of (major * 10000 + minor * 100 + patch)
-// For example, 3.1.2 becomes 30102.
-#define ZEEK_VERSION_NUMBER @ZEEK_VERSION_NUMBER@
-
 /* whether words are stored with the most significant byte first */
 #cmakedefine WORDS_BIGENDIAN
 
@@ -251,19 +243,18 @@
 /* String with extension of dynamic libraries (e.g., ".so") */
 #define DYNAMIC_PLUGIN_SUFFIX "@CMAKE_SHARED_MODULE_SUFFIX@"
 
-/* True if we're building outside of the main Zeek source code tree. */
+/* Set if we're building outside of the main Zeek source code tree. */
 #ifndef ZEEK_PLUGIN_INTERNAL_BUILD
-#define ZEEK_PLUGIN_INTERNAL_BUILD @ZEEK_PLUGIN_INTERNAL_BUILD@
+#define ZEEK_PLUGIN_INTERNAL_BUILD true
+#else
+// Backwards compat for external plugins, include the version
+// identifiers through zeek/zeek-version.h.
+#if ! ZEEK_PLUGIN_INTERNAL_BUILD
+#include "zeek/zeek-version.h"
 #endif
-
-/* A C function that has the Zeek version encoded into its name. */
-#define ZEEK_VERSION_FUNCTION zeek_version_@VERSION_C_IDENT@
-#ifdef __cplusplus
-extern "C" {
-#endif
-extern const char* ZEEK_VERSION_FUNCTION();
-#ifdef __cplusplus
-}
+//
+// Not sure we can ever deprecate this without changing
+// the names.
 #endif
 
 // GCC uses __SANITIZE_ADDRESS__, Clang uses __has_feature

zeek-version.h.in

@@ -0,0 +1,19 @@
+#pragma once
+
+/* Version number of package */
+#define VERSION "@VERSION@"
+
+// Zeek version number.
+// This is the result of (major * 10000 + minor * 100 + patch)
+// For example, 3.1.2 becomes 30102.
+#define ZEEK_VERSION_NUMBER @ZEEK_VERSION_NUMBER@
+
+/* A C function that has the Zeek version encoded into its name. */
+#define ZEEK_VERSION_FUNCTION zeek_version_@VERSION_C_IDENT@
+#ifdef __cplusplus
+extern "C" {
+#endif
+extern const char* ZEEK_VERSION_FUNCTION();
+#ifdef __cplusplus
+}
+#endif