Merge "Make prebuilt_apex report an error if no apex file is found" am: 846ce57a00

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/1665740

Change-Id: Ifa76e593f32b529fa7993bb6a63c978b2cd0b92e

apex/apex_test.go

@@ -4316,6 +4316,14 @@ func TestPrebuilt(t *testing.T) {
 	}
 }
 
+func TestPrebuiltMissingSrc(t *testing.T) {
+	testApexError(t, `module "myapex" variant "android_common".*: prebuilt_apex does not support "arm64_armv8-a"`, `
+		prebuilt_apex {
+			name: "myapex",
+		}
+	`)
+}
+
 func TestPrebuiltFilenameOverride(t *testing.T) {
 	ctx := testApex(t, `
 		prebuilt_apex {

apex/prebuilt.go

@@ -152,14 +152,17 @@ func (p *ApexFileProperties) prebuiltApexSelector(ctx android.BaseModuleContext,
 		src = String(p.Arch.X86.Src)
 	case android.X86_64:
 		src = String(p.Arch.X86_64.Src)
-	default:
-		ctx.OtherModuleErrorf(prebuilt, "prebuilt_apex does not support %q", multiTargets[0].Arch.String())
-		return nil
 	}
 	if src == "" {
 		src = String(p.Src)
 	}
 
+	if src == "" {
+		ctx.OtherModuleErrorf(prebuilt, "prebuilt_apex does not support %q", multiTargets[0].Arch.String())
+		// Drop through to return an empty string as the src (instead of nil) to avoid the prebuilt
+		// logic from reporting a more general, less useful message.
+	}
+
 	return []string{src}
 }