From 5d5fcc3092997fe5b528d6ab519b244ea8e99a6d Mon Sep 17 00:00:00 2001
From: Cole Faust <colefaust@google.com>
Date: Tue, 26 Apr 2022 18:02:05 -0700
Subject: [PATCH] Ignore assignments to .KATI_READONLY

Since the rbc results file is sorted, .KATI_READONLY
ends up trying to make a variable that hasn't been defined
yet readonly, which is an error.

It's not really worth supporting moving it down in the list,
because it wouldn't affect the variable being writable while
still in Starlark code.

Bug: 226974242
Test: go test
Change-Id: I9402f69be97e5c7cf010ad86f124422ea55fda7f
---
 mk2rbc/mk2rbc.go      |  6 ++++++
 mk2rbc/mk2rbc_test.go | 14 ++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/mk2rbc/mk2rbc.go b/mk2rbc/mk2rbc.go
index 8f4fea4b1..4d777a05c 100644
--- a/mk2rbc/mk2rbc.go
+++ b/mk2rbc/mk2rbc.go
@@ -542,6 +542,12 @@ func (ctx *parseContext) handleAssignment(a *mkparser.Assignment) []starlarkNode
 	if strings.HasPrefix(name, "override ") {
 		return []starlarkNode{ctx.newBadNode(a, "cannot handle override directive")}
 	}
+	if name == ".KATI_READONLY" {
+		// Skip assignments to .KATI_READONLY. If it was in the output file, it
+		// would be an error because it would be sorted before the definition of
+		// the variable it's trying to make readonly.
+		return []starlarkNode{}
+	}
 
 	// Soong configuration
 	if strings.HasPrefix(name, soongNsPrefix) {
diff --git a/mk2rbc/mk2rbc_test.go b/mk2rbc/mk2rbc_test.go
index de7512927..1287cfd16 100644
--- a/mk2rbc/mk2rbc_test.go
+++ b/mk2rbc/mk2rbc_test.go
@@ -1527,6 +1527,20 @@ def init(g, handle):
     cfg["PRODUCT_COPY_FILES"] += ("foo/bar/%s:%s/etc/%s" % (x, g.get("TARGET_COPY_OUT_VENDOR", ""), x)).split()
     if g.get("MY_OTHER_VAR", ""):
       cfg["PRODUCT_COPY_FILES"] += ("%s:foo/bar/%s" % (g.get("MY_OTHER_VAR", ""), x)).split()
+`,
+	},
+	{
+		desc:   ".KATI_READONLY",
+		mkname: "product.mk",
+		in: `
+MY_VAR := foo
+.KATI_READONLY := MY_VAR
+`,
+		expected: `load("//build/make/core:product_config.rbc", "rblf")
+
+def init(g, handle):
+  cfg = rblf.cfg(handle)
+  g["MY_VAR"] = "foo"
 `,
 	},
 }