Bug 1329726 - part 2 - ensure {,HOST_}RUST_PROGRAMS are hooked into root-deps.mk; r=chmanchester

If we don't do this, a directory with only
RUST_PROGRAMS (resp. HOST_RUST_PROGRAMS) won't get traversed properly.

python/mozbuild/mozbuild/backend/recursivemake.py

@@ -539,13 +539,16 @@ class RecursiveMakeBackend(CommonBackend):
             backend_file.write('JAR_MANIFEST := %s\n' % obj.path.full_path)
 
         elif isinstance(obj, RustProgram):
-            # Note that for these and host Rust programs, we don't need to
-            # bother with linked libraries, because Cargo will take care of
-            # all of that for us.
             self._process_rust_program(obj, backend_file)
+            # Hook the program into the compile graph.
+            build_target = self._build_target_for_obj(obj)
+            self._compile_graph[build_target]
 
         elif isinstance(obj, HostRustProgram):
             self._process_host_rust_program(obj, backend_file)
+            # Hook the program into the compile graph.
+            build_target = self._build_target_for_obj(obj)
+            self._compile_graph[build_target]
 
         elif isinstance(obj, Program):
             self._process_program(obj.program, backend_file)

python/mozbuild/mozbuild/test/backend/data/rust-programs/code/moz.build

@@ -0,0 +1,6 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# Any copyright is dedicated to the Public Domain.
+# http://creativecommons.org/publicdomain/zero/1.0/
+
+RUST_PROGRAMS += ['target']
+HOST_RUST_PROGRAMS += ['host']

python/mozbuild/mozbuild/test/backend/data/rust-programs/moz.build

@@ -2,5 +2,4 @@
 # Any copyright is dedicated to the Public Domain.
 # http://creativecommons.org/publicdomain/zero/1.0/
 
-RUST_PROGRAMS += ['target']
-HOST_RUST_PROGRAMS += ['host']
+DIRS += ['code']

python/mozbuild/mozbuild/test/backend/test_recursivemake.py

@@ -768,11 +768,11 @@ class TestRecursiveMakeBackend(BackendTester):
         """Test that {HOST_,}RUST_PROGRAMS are written to backend.mk correctly."""
         env = self._consume('rust-programs', RecursiveMakeBackend)
 
-        backend_path = mozpath.join(env.topobjdir, 'backend.mk')
+        backend_path = mozpath.join(env.topobjdir, 'code/backend.mk')
         lines = [l.strip() for l in open(backend_path, 'rt').readlines()[2:]]
 
         expected = [
-            'CARGO_FILE := %s/Cargo.toml' % env.topsrcdir,
+            'CARGO_FILE := %s/code/Cargo.toml' % env.topsrcdir,
             'RUST_PROGRAMS += i686-pc-windows-msvc/release/target.exe',
             'RUST_CARGO_PROGRAMS += target',
             'HOST_RUST_PROGRAMS += i686-pc-windows-msvc/release/host.exe',
@@ -781,6 +781,11 @@ class TestRecursiveMakeBackend(BackendTester):
 
         self.assertEqual(lines, expected)
 
+        root_deps_path = mozpath.join(env.topobjdir, 'root-deps.mk')
+        lines = [l.strip() for l in open(root_deps_path, 'rt').readlines()]
+
+        self.assertTrue(any(l == 'recurse_compile: code/host code/target' for l in lines))
+
     def test_final_target(self):
         """Test that FINAL_TARGET is written to backend.mk correctly."""
         env = self._consume('final_target', RecursiveMakeBackend)