Add a Make rule to touch the build tree

Ref. eng/recordflux/RecordFlux#1743

.gitlab-ci.yml

@@ -132,18 +132,8 @@ setup:
         . .venv$PYTHON_VERSION/bin/activate;
         make init;
       fi
-    # Prevent regeneration of Langkit-based parser.
-    # The full set of dependencies must be touched in the relative build order.
-    - touch .venv$PYTHON_VERSION/lib/python$PYTHON_VERSION/site-packages/langkit
-    - touch generated/python/librflxlang
-    - touch generated/lib/relocatable/dev/librflxlang.so
-    - touch rflx/lang/librflxlang.so
-    # Prevent recompilation of RapidFlux library.
-    - find librapidflux rapidflux -type f -exec touch {} \;
-    - touch target/debug/librapidflux.so
-    - touch rflx/rapidflux.so
-    # Prevent reinstallation of RecordFlux
-    - touch .venv$PYTHON_VERSION/bin/rflx
+    # Prevent the regeneration and rebuild of RecordFlux and its components
+    - make touch_build_tree
 
 changelog:
   rules:

Makefile

@@ -645,6 +645,26 @@ audit: $(RFLX) rapidflux_devel
 	@echo Auditing Rust dependencies
 	@cargo audit
 
+# --- Workflow optimization utilities ---
+
+.PHONY: touch_build_tree
+
+# Touch the main build artifacts to mark them up to date to prevent their
+# recompilation when that isn't required and desirable. The order of touching
+# must correspond to the relative build order.
+touch_build_tree:
+	@# Langkit-based parser
+	touch $(BUILD_DEPS)
+	touch $(GENERATED_DIR)/python/librflxlang
+	touch $(GENERATED_DIR)/lib/relocatable/dev/librflxlang.so
+	touch $(PARSER)
+	@# RapidFlux
+	find librapidflux rapidflux -type f -exec touch {} +
+	touch target/debug/librapidflux.so
+	touch $(RAPIDFLUX)
+	@# RecordFlux
+	touch $(DEVEL_VENV)/bin/rflx
+
 # --- Clean ---
 
 .PHONY: clean clean_build clean_cache clean_all