Only set TARGET_PLATFORM version in lunch when explicitly requested

Setting TARGET_PLATFORM_VERSION to DEFAULT_PLATFORM_VERSION during
"lunch sailfish-userdebug" causes unnecessary pain when
DEFAULT_PLATFORM_VERSION becomes invalid after branching.  Only
set TARGET_PLATFORM_VERSION if it was explicitly requested with
lunch sailfish-userdebug-OPR1.

Test: build/make/tests/envsetup_tests.sh
Bug: 34972208
Bug: 37208937
Change-Id: I40ba4617e73803c5bec1a8d317382f70fb3ec3a2

core/version_defaults.mk

@@ -49,6 +49,12 @@ ALLOWED_VERSIONS := $(call allowed-platform-versions,\
 
 ifndef TARGET_PLATFORM_VERSION
   TARGET_PLATFORM_VERSION := $(DEFAULT_PLATFORM_VERSION)
+else ifeq ($(TARGET_PLATFORM_VERSION),OPR1)
+  # HACK: lunch currently sets TARGET_PLATFORM_VERSION to
+  # DEFAULT_PLATFORM_VERSION, which causes unnecessary pain
+  # when the old DEFAULT_PLATFORM_VERSION becomes invalid.
+  # For now, silently upgrade OPR1 to the current default.
+  TARGET_PLATFORM_VERSION := $(DEFAULT_PLATFORM_VERSION)
 endif
 
 ifeq (,$(filter $(ALLOWED_VERSIONS), $(TARGET_PLATFORM_VERSION)))

envsetup.sh

@@ -620,7 +620,11 @@ function lunch()
 
     export TARGET_PRODUCT=$(get_build_var TARGET_PRODUCT)
     export TARGET_BUILD_VARIANT=$(get_build_var TARGET_BUILD_VARIANT)
-    export TARGET_PLATFORM_VERSION=$(get_build_var TARGET_PLATFORM_VERSION)
+    if [ -n "$version" ]; then
+      export TARGET_PLATFORM_VERSION=$(get_build_var TARGET_PLATFORM_VERSION)
+    else
+      unset TARGET_PLATFORM_VERSION
+    fi
     export TARGET_BUILD_TYPE=release
 
     echo

tests/envsetup_tests.sh

@@ -19,8 +19,9 @@ default_version=$(get_build_var DEFAULT_PLATFORM_VERSION)
 valid_version=PPR1
 
 # lunch tests
-check_lunch "aosp_arm64"                                "aosp_arm64" "eng"       "$default_version"
-check_lunch "aosp_arm64-userdebug"                      "aosp_arm64" "userdebug" "$default_version"
+check_lunch "aosp_arm64"                                "aosp_arm64" "eng"       ""
+check_lunch "aosp_arm64-userdebug"                      "aosp_arm64" "userdebug" ""
+check_lunch "aosp_arm64-userdebug-$default_version"     "aosp_arm64" "userdebug" "$default_version"
 check_lunch "aosp_arm64-userdebug-$valid_version"       "aosp_arm64" "userdebug" "$valid_version"
 check_lunch "abc"                                       "" "" ""
 check_lunch "aosp_arm64-abc"                            "" "" ""