[make] ignore copy-copy races in clang compilation db tests

Summary: concurrency-with-parallelism

Reviewed By: mbouaziz

Differential Revision: D7908386

fbshipit-source-id: a1d7ae5

Makefile.config

@@ -106,6 +106,10 @@ CLANG_DEPS_NO_MODELS = \
 CLANG_DEPS = $(CLANG_DEPS_NO_MODELS) $(MODELS_RESULTS_FILE) \
   $(shell find $(MODELS_DIR)/cpp/include -type f)
 
+define copy_or_same_file
+  $(COPY) "$(1)" "$(2)" || diff -q "$(1)" "$(2)"
+endef
+
 INTERACTIVE = $(shell [ -t 0 ] && echo 1)
 # remove "jobserver-fds" because it contains "s"...
 SILENT = $(findstring s,$(subst jobserver-fds,,$(MAKEFLAGS)))

infer/tests/build_systems/clang_compilation_db_escaped/Makefile

@@ -19,7 +19,8 @@ include $(TESTS_DIR)/infer.make
 ../codetoanalyze/path\ with\ spaces/hel\ lo.c: ../codetoanalyze/path_with_spaces/hel_lo.c
 #	make does not want to interpret "$(@D)" in the right way here...
 	$(QUIET)$(MKDIR_P) ../codetoanalyze/path\ with\ spaces/
-	$(QUIET)cp "$<" "$@"
+#	allow copy races with other tests if they are doing the same action
+	$(QUIET)$(call copy_or_same_file,$<,$@)
 	$(QUIET)touch "$@"
 
 compile_commands.json: compile_commands.json.in

infer/tests/build_systems/clang_compilation_db_relpath/Makefile

@@ -21,7 +21,8 @@ include $(TESTS_DIR)/infer.make
 ../codetoanalyze/path\ with\ spaces/hel\ lo.c ../codetoanalyze/path\ with\ spaces/hel\ lo2.c:
 #	make does not want to interpret "$(@D)" in the right way here...
 	$(QUIET)$(MKDIR_P) ../codetoanalyze/path\ with\ spaces/
-	$(QUIET)cp "$<" "$@"
+#	allow copy races with other tests if they are doing the same action
+	$(QUIET)$(call copy_or_same_file,$<,$@)
 	$(QUIET)touch "$@"
 ../codetoanalyze/path\ with\ spaces/hel\ lo.c: ../codetoanalyze/path_with_spaces/hel_lo.c
 ../codetoanalyze/path\ with\ spaces/hel\ lo2.c: ../codetoanalyze/path_with_spaces/hel_lo2.c