fix: make bt4_picknik tools and vendored lexy disjoint from stock

CMakeLists.txt

@@ -92,7 +92,38 @@ endif()
 #############################################################
 # LIBRARY
 
+# lexy is linked PRIVATE/BUILD_INTERFACE-only (see the target_link_libraries
+# calls below) and its only consumer, src/script_parser.cpp, is compiled into
+# this library itself. No header reachable from the public entry points
+# (behavior_tree.h / bt_factory.h / basic_types.h) includes lexy; the
+# scripting/operators.hpp -> any_types.hpp chain does, but it is parser-internal
+# and consumed only by src/script_parser.cpp. So installing lexy's own
+# headers/CMake config/static lib is dead weight that would otherwise collide
+# with any stock behaviortree_cpp snapshot that also vendors lexy unscoped
+# (issue #20928). Disable lexy's own install rule before pulling it in.
+#
+# CACHE ... FORCE is configure-wide, not scoped to this add_subdirectory() call:
+# if this project is itself embedded via add_subdirectory() alongside another,
+# unrelated lexy instance, forcing this cache entry OFF would also suppress
+# that instance's install rules for the rest of the configure run. Save the
+# caller's prior cache state (absent or a value) and restore it once lexy's own
+# option(LEXY_ENABLE_INSTALL ...) has read our forced OFF -- restoring after
+# add_subdirectory() returns is safe because that option() call, not any later
+# read, is what CMP0077-OLD in 3rdparty/lexy/CMakeLists.txt makes CACHE FORCE
+# necessary for in the first place.
+if(DEFINED CACHE{LEXY_ENABLE_INSTALL})
+    set(_btcpp_picknik_prev_lexy_enable_install "${LEXY_ENABLE_INSTALL}")
+else()
+    unset(_btcpp_picknik_prev_lexy_enable_install)
+endif()
+set(LEXY_ENABLE_INSTALL OFF CACHE BOOL "Disabled by behaviortree_cpp_picknik, see comment above" FORCE)
 add_subdirectory(3rdparty/lexy)
+if(DEFINED _btcpp_picknik_prev_lexy_enable_install)
+    set(LEXY_ENABLE_INSTALL "${_btcpp_picknik_prev_lexy_enable_install}" CACHE BOOL "Disabled by behaviortree_cpp_picknik, see comment above" FORCE)
+    unset(_btcpp_picknik_prev_lexy_enable_install)
+else()
+    unset(LEXY_ENABLE_INSTALL CACHE)
+endif()
 
 add_library(minitrace STATIC 3rdparty/minitrace/minitrace.cpp)
 target_compile_definitions(minitrace PRIVATE MTR_ENABLED=True)

tools/CMakeLists.txt

@@ -1,19 +1,22 @@
 
 include_directories(${PROJECT_SOURCE_DIR}/3rdparty)
 
-# add_executable(bt4_log_cat         bt_log_cat.cpp )
-# target_link_libraries(bt4_log_cat  ${BTCPP_LIBRARY} )
-# install(TARGETS bt4_log_cat
+# add_executable(bt4_picknik_log_cat         bt_log_cat.cpp )
+# target_link_libraries(bt4_picknik_log_cat  ${BTCPP_LIBRARY} )
+# install(TARGETS bt4_picknik_log_cat
 #         DESTINATION ${BTCPP_BIN_DESTINATION} )
 
+# bt4_picknik_* names (rather than upstream's bt4_*) so no bin/ path collides
+# with stock upstream behaviortree_cpp, which installs identically-named
+# tools at the same unscoped destination (issue #20928).
 if( ZMQ_FOUND )
-    add_executable(bt4_recorder         bt_recorder.cpp )
-    target_link_libraries(bt4_recorder  ${BTCPP_LIBRARY} ${ZMQ_LIBRARIES})
-    install(TARGETS bt4_recorder
+    add_executable(bt4_picknik_recorder         bt_recorder.cpp )
+    target_link_libraries(bt4_picknik_recorder  ${BTCPP_LIBRARY} ${ZMQ_LIBRARIES})
+    install(TARGETS bt4_picknik_recorder
             DESTINATION ${BTCPP_BIN_DESTINATION} )
 endif()
 
-add_executable(bt4_plugin_manifest         bt_plugin_manifest.cpp )
-target_link_libraries(bt4_plugin_manifest  ${BTCPP_LIBRARY} )
-install(TARGETS bt4_plugin_manifest
+add_executable(bt4_picknik_plugin_manifest         bt_plugin_manifest.cpp )
+target_link_libraries(bt4_picknik_plugin_manifest  ${BTCPP_LIBRARY} )
+install(TARGETS bt4_picknik_plugin_manifest
         DESTINATION ${BTCPP_BIN_DESTINATION} )