fix: made code more resilient to missing/broken references

pbxproj/XcodeProject.py

@@ -1,5 +1,6 @@
 import shutil
 import datetime
+import sys
 from pbxproj.pbxextensions import *
 
 
@@ -26,13 +27,21 @@ def __init__(self, tree=None, path=None):
         if 'objects' not in self:
             return
 
+        missing_references = False
         for section in self.objects.get_sections():
             for obj in self.objects.get_objects_in_section(section):
                 if 'files' in obj and obj['files'] is not None:
                     comment = obj._get_comment()
                     for file_id in obj['files']:
-                        # set the section into the objects
-                        self.objects[file_id]._section = comment
+                        if self.objects[file_id] is not None:
+                            # set the section into the objects
+                            self.objects[file_id]._section = comment
+                        else:
+                            missing_references = True
+
+        if missing_references:
+            print('[WARNING] The project contains missing/broken references that may cause other problems.'
+                  ' Open your project in Xcode and resolve all red-colored files.', file=sys.stderr)
 
     def save(self, path=None):
         if path is None:

pbxproj/pbxextensions/ProjectFiles.py

@@ -174,6 +174,9 @@ def _filter_targets_without_path(self, path, target_name):
                 build_phase = self.get_object(build_phase_id)
                 for build_file_id in build_phase.files:
                     build_file = self.get_object(build_file_id)
+                    if build_file is None:
+                        continue
+
                     file_ref = self.get_object(build_file.fileRef)
                     if 'path' in file_ref and ProjectFiles._path_leaf(path) == ProjectFiles._path_leaf(file_ref.path):
                         potential_targets.remove(target)
@@ -316,6 +319,9 @@ def remove_file_by_id(self, file_id, target_name=None):
                 build_phase = self.objects[build_phase_id]
 
                 for build_file_id in build_phase.files:
+                    if build_file_id not in self.objects:
+                        continue
+
                     build_file = self.objects[build_file_id]
 
                     if build_file.fileRef == file_ref.get_id():

tests/pbxcli/TestPBXCLI.py

@@ -65,3 +65,10 @@ def testCommandWithFailure(self):
         with self.assertRaisesRegex(SystemExit, '^1'):
             parser({u'<project>': u'whatever/project.pbxproj', u'--backup': False})
         self.assertEqual(sys.stdout.getvalue().strip(), u'Project file not found')
+
+    def testOpenFileWithBrokenReferences(self):
+        sys.stderr = StringIO()
+        project = open_project({'<project>': 'samplescli/broken-references.pbxproj'})
+        self.assertEqual(sys.stderr.getvalue().strip(), '[WARNING] The project contains missing/broken references that '
+                                                        'may cause other problems. Open your project in Xcode and '
+                                                        'resolve all red-colored files.')