Mark (BUILD_|LOCAL_)COPY_HEADERS as [more] deprecated

We've considered these deprecated for a while, and have reduced where
they may be used, but let's actually throw warnings and call them out
specifically now.

Bug: 130719878
Test: lunch aosp_arm; m nothing   [see no warnings]
Test: lunch aosp_crosshatch; m nothing   [see LOCAL_COPY_HEADERS warnings]
Test: lunch aosp_taimen; m nothing  [see BUILD_COPY_HEADERS warnings]
Change-Id: I8c12012366d84667de0d223bbde38d8b90419e36

Changes.md

@@ -1,5 +1,14 @@
 # Build System Changes for Android.mk Writers
 
+## COPY_HEADERS usage now produces warnings {#copy_headers}
+
+We've considered `BUILD_COPY_HEADERS`/`LOCAL_COPY_HEADERS` to be deprecated for
+a long time, and the places where it's been able to be used have shrinked over
+the last several releases. Equivalent functionality is not available in Soong.
+
+See the [build/soong/docs/best_practices.md#headers] for more information about
+how best to handle headers in Android.
+
 ## `m4` is not available on `$PATH`
 
 There is a prebuilt of it available in prebuilts/build-tools, and a make
@@ -553,6 +562,7 @@ version.
 
 
 [build/soong/Changes.md]: https://android.googlesource.com/platform/build/soong/+/master/Changes.md
+[build/soong/docs/best_practices.md#headers]: https://android.googlesource.com/platform/build/soong/+/master/docs/best_practices.md#headers
 [external/fonttools/Lib/fontTools/Android.bp]: https://android.googlesource.com/platform/external/fonttools/+/master/Lib/fontTools/Android.bp
 [frameworks/base/Android.bp]: https://android.googlesource.com/platform/frameworks/base/+/master/Android.bp
 [frameworks/base/data/fonts/Android.mk]: https://android.googlesource.com/platform/frameworks/base/+/master/data/fonts/Android.mk

Deprecation.md

@@ -16,6 +16,7 @@ have any problems converting, please contact us via:
 | -------------------------------- | --------- |
 | `BUILD_AUX_EXECUTABLE`           | Error     |
 | `BUILD_AUX_STATIC_LIBRARY`       | Error     |
+| `BUILD_COPY_HEADERS`             | Warning   |
 | `BUILD_HOST_FUZZ_TEST`           | Error     |
 | `BUILD_HOST_NATIVE_TEST`         | Error     |
 | `BUILD_HOST_SHARED_LIBRARY`      | Warning   |

core/board_config.mk

@@ -621,11 +621,15 @@ endif
 ###########################################
 # Handle BUILD_BROKEN_USES_BUILD_*
 
-$(foreach m,$(DEFAULT_WARNING_BUILD_MODULE_TYPES),\
+$(foreach m,$(filter-out BUILD_COPY_HEADERS,$(DEFAULT_WARNING_BUILD_MODULE_TYPES)),\
   $(if $(filter false,$(BUILD_BROKEN_USES_$(m))),\
     $(KATI_obsolete_var $(m),Please convert to Soong),\
     $(KATI_deprecated_var $(m),Please convert to Soong)))
 
+$(if $(filter false,$(BUILD_BROKEN_USES_BUILD_COPY_HEADERS)),\
+  $(KATI_obsolete_var BUILD_COPY_HEADERS,See $(CHANGES_URL)#copy_headers),\
+  $(KATI_deprecated_var BUILD_COPY_HEADERS,See $(CHANGES_URL)#copy_headers))
+
 $(foreach m,$(DEFAULT_ERROR_BUILD_MODULE_TYPES),\
   $(if $(filter true,$(BUILD_BROKEN_USES_$(m))),\
     $(KATI_deprecated_var $(m),Please convert to Soong),\

core/deprecation.mk

@@ -1,6 +1,5 @@
 # These module types can still be used without warnings or errors.
 AVAILABLE_BUILD_MODULE_TYPES :=$= \
-  BUILD_COPY_HEADERS \
   BUILD_EXECUTABLE \
   BUILD_FUZZ_TEST \
   BUILD_HEADER_LIBRARY \
@@ -26,6 +25,7 @@ AVAILABLE_BUILD_MODULE_TYPES :=$= \
 # relevant BUILD_BROKEN_USES_BUILD_* variables, then these would move to
 # DEFAULT_ERROR_BUILD_MODULE_TYPES.
 DEFAULT_WARNING_BUILD_MODULE_TYPES :=$= \
+  BUILD_COPY_HEADERS \
   BUILD_HOST_SHARED_LIBRARY \
   BUILD_HOST_STATIC_LIBRARY \
 

core/host_shared_library.mk

@@ -37,4 +37,7 @@ my_module_arch_supported :=
 ###########################################################
 ## Copy headers to the install tree
 ###########################################################
-include $(BUILD_COPY_HEADERS)
+ifdef LOCAL_COPY_HEADERS
+$(call pretty-warning,LOCAL_COPY_HEADERS is deprecated. See $(CHANGES_URL)#copy_headers)
+include $(BUILD_SYSTEM)/copy_headers.mk
+endif

core/host_static_library.mk

@@ -37,4 +37,7 @@ my_module_arch_supported :=
 ###########################################################
 ## Copy headers to the install tree
 ###########################################################
-include $(BUILD_COPY_HEADERS)
+ifdef LOCAL_COPY_HEADERS
+$(call pretty-warning,LOCAL_COPY_HEADERS is deprecated. See $(CHANGES_URL)#copy_headers)
+include $(BUILD_SYSTEM)/copy_headers.mk
+endif

core/shared_library.mk

@@ -56,4 +56,7 @@ my_module_arch_supported :=
 ###########################################################
 ## Copy headers to the install tree
 ###########################################################
-include $(BUILD_COPY_HEADERS)
+ifdef LOCAL_COPY_HEADERS
+$(call pretty-warning,LOCAL_COPY_HEADERS is deprecated. See $(CHANGES_URL)#copy_headers)
+include $(BUILD_SYSTEM)/copy_headers.mk
+endif

core/static_library.mk

@@ -41,4 +41,7 @@ my_module_arch_supported :=
 ###########################################################
 ## Copy headers to the install tree
 ###########################################################
-include $(BUILD_COPY_HEADERS)
+ifdef LOCAL_COPY_HEADERS
+$(call pretty-warning,LOCAL_COPY_HEADERS is deprecated. See $(CHANGES_URL)#copy_headers)
+include $(BUILD_SYSTEM)/copy_headers.mk
+endif