[build] Add missing commentary about testonly in fidl_library()
Describe the previous fidl_library() change in the doc comments.
Change-Id: Ifdc61aa45a8c20a4e640f9573d570aea66f8be66
diff --git a/zircon/public/gn/fidl.gni b/zircon/public/gn/fidl.gni
index 3d466c2..38bdc31 100644
--- a/zircon/public/gn/fidl.gni
+++ b/zircon/public/gn/fidl.gni
@@ -123,7 +123,10 @@
# Parameters
#
# sources
-# Required: List of `.fidl` source files.
+# Required: List of `.fidl` source files. Note that if any file names
+# ending in `.test.fidl` are present, $testonly is automatically set
+# to true and cannot be explicitly set to false.
+# Type: list(file)
#
# deps
# Optional: This is *not* the way to express dependencies on other FIDL
@@ -143,6 +146,11 @@
# Type: bool
# Default: false
#
+# testonly
+# Optional: Usual GN meaning: dependent targets must also set $testonly.
+# Type: bool
+# Default: true iff $sources includes "*.test.fidl" files
+#
template("fidl_library") {
assert(defined(invoker.sources),
"fidl_library(\"$target_name\") must set `sources`")
