# HG changeset patch
# User Chris Manchester <cmanchester@mozilla.com>
# Date 1525718954 25200
#      Mon May 07 11:49:14 2018 -0700
# Node ID 6af5cfa13600d062c48606496d8235d83ac62137
# Parent  cb9914ab3220d51b6f97538574eb8ac8ba1a96b7
Bug 1459074 - Do not fail when installing tests if the install manifest for test harness files is missing. r=mshal

MozReview-Commit-ID: 4zp0eANlO9G

diff --git a/python/mozbuild/mozbuild/testing.py b/python/mozbuild/mozbuild/testing.py
--- a/python/mozbuild/mozbuild/testing.py
+++ b/python/mozbuild/mozbuild/testing.py
@@ -250,21 +250,24 @@ def install_test_files(topsrcdir, topobj
         if dest in install_info.external_installs:
             continue
         manifest.add_link(source, dest)
     for base, pattern, dest in install_info.pattern_installs:
         manifest.add_pattern_link(base, pattern, dest)
 
     _resolve_installs(install_info.deferred_installs, topobjdir, manifest)
 
-    # Harness files are treated as a monolith and installed each time we run tests.
-    # Fortunately there are not very many.
-    manifest |= InstallManifest(mozpath.join(topobjdir,
-                                             '_build_manifests',
-                                             'install', tests_root))
+    harness_files_manifest = mozpath.join(topobjdir, '_build_manifests',
+                                          'install', tests_root)
+    if os.path.isfile(harness_files_manifest):
+        # If the backend has generated an install manifest for test harness
+        # files they are treated as a monolith and installed each time we
+        # run tests. Fortunately there are not very many.
+        manifest |= InstallManifest(harness_files_manifest)
+
     copier = FileCopier()
     manifest.populate_registry(copier)
     copier.copy(objdir_dest,
                 remove_unaccounted=False)
 
 
 # Convenience methods for test manifest reading.
 def read_manifestparser_manifest(context, manifest_path):