Fix CMake unit test race condition

cmake/test/data/TestDeployment/TestChainedAutocoder/CMakeLists.txt

@@ -1,3 +1,8 @@
+# Opt out of target/test_autocoder. target/test_chained_autocoder runs test_target_autocoder
+# itself (as the first stage of the chain), so applying both targets to this module would
+# duplicate the same `cmake -E copy` rule into two sub-makefiles and race under `make -jN`.
+# Custom targets are attached inside register_fprime_module, so the flag must be set first.
+set(SKIP_TEST_AUTOCODER_TARGET TRUE)
 register_fprime_module(
         TestChainedAutocoderModule
     AUTOCODER_INPUTS
@@ -6,3 +11,4 @@ register_fprime_module(
     EXCLUDE_FROM_ALL
     INTERFACE
 )
+unset(SKIP_TEST_AUTOCODER_TARGET)

cmake/test/data/TestDeployment/TestTargetAutocoder/CMakeLists.txt

@@ -1,3 +1,9 @@
+# Opt out of target/test_chained_autocoder. This module exercises the standalone
+# target/test_autocoder; without this, the chained target would also run test_target_autocoder
+# on it and CMake would emit the same `cmake -E copy` rule into two sub-makefiles, racing
+# under `make -jN`. Custom targets are attached inside register_fprime_module, so the flag
+# must be set first.
+set(SKIP_TEST_CHAINED_AUTOCODER_TARGET TRUE)
 register_fprime_module(
         TestTargetAutocoderModule
     AUTOCODER_INPUTS
@@ -6,4 +12,5 @@ register_fprime_module(
     EXCLUDE_FROM_ALL
     INTERFACE
 )
+unset(SKIP_TEST_CHAINED_AUTOCODER_TARGET)
 target_include_directories(TestBuildAutocoderModule PRIVATE "${CMAKE_CURRENT_BINARY_DIR}")

cmake/test/data/cmake/target/test_autocoder.cmake

@@ -12,6 +12,11 @@ function(test_autocoder_add_deployment_target MODULE TARGET SOURCES DIRECT_DEPEN
 endfunction(test_autocoder_add_deployment_target)
 
 function(test_autocoder_add_module_target MODULE TARGET SOURCES DEPENDENCIES)
+    # Allow modules to opt out (e.g. TestChainedAutocoderModule, which owns its own
+    # run of test_target_autocoder via target/test_chained_autocoder).
+    if (SKIP_TEST_AUTOCODER_TARGET)
+        return()
+    endif()
     run_ac_set("${MODULE}" "autocoder/test_target_autocoder")
     # Use the variable from this run as set by the autocoder
     add_custom_target("${MODULE}_test_autocode" DEPENDS "${AUTOCODER_GENERATED_OTHER}")

cmake/test/data/cmake/target/test_chained_autocoder.cmake

@@ -12,9 +12,14 @@ function(test_chained_autocoder_add_deployment_target MODULE TARGET SOURCES DIRE
 endfunction(test_chained_autocoder_add_deployment_target)
 
 function(test_chained_autocoder_add_module_target MODULE TARGET SOURCES DEPENDENCIES)
+    # Allow modules to opt out (e.g. TestTargetAutocoderModule, which exercises the standalone
+    # target/test_autocoder). See note in test_autocoder.cmake.
+    if (SKIP_TEST_CHAINED_AUTOCODER_TARGET)
+        return()
+    endif()
     # Run both autocoders in sequence: target autocoder first, then chained autocoder
     run_ac_set("${MODULE}" "autocoder/test_target_autocoder" "autocoder/test_chained_autocoder")
-    
+
     # Use the variable from this run as set by the autocoders
     add_custom_target("${MODULE}_test_chained_autocode" DEPENDS "${AUTOCODER_GENERATED_OTHER}")
     add_dependencies("${MODULE}" "${MODULE}_test_chained_autocode")