fix 'NoneType' object is not subscriptable (#160)

Fix for https://l.codecov.dev/hqZ1Ci (Sentry issue)

The error itself is `TypeError: 'NoneType' object is not subscriptable`.
This was happening because if we don't have static analysis for a file
the lines relevant for that file might be `None`, and we we're not checking
this condition prior to starting to access the dict items.

The fix itself is very simple, but I wanted to add type hints and better
tests too, so they're in the change as well.

tasks/label_analysis.py

@@ -1,5 +1,5 @@
 import logging
-from typing import List, Optional, Set, Tuple
+from typing import Dict, List, Optional, Set, Tuple, TypedDict
 
 import sentry_sdk
 from shared.celery_config import label_analysis_task_name
@@ -30,6 +30,16 @@
 )
 
 
+class LinesRelevantToChangeInFile(TypedDict):
+    all: bool
+    lines: Set[int]
+
+
+class LinesRelevantToChange(TypedDict):
+    all: bool
+    files: Dict[str, Optional[LinesRelevantToChangeInFile]]
+
+
 class LabelAnalysisRequestProcessingTask(
     BaseCodecovTask, name=label_analysis_task_name
 ):
@@ -75,9 +85,9 @@ async def run_async(self, db_session, request_id, *args, **kwargs):
             return self._handle_larq_already_calculated(label_analysis_request)
 
         try:
-            lines_relevant_to_diff = await self._get_lines_relevant_to_diff(
-                label_analysis_request
-            )
+            lines_relevant_to_diff: Optional[
+                LinesRelevantToChange
+            ] = await self._get_lines_relevant_to_diff(label_analysis_request)
             base_report = self._get_base_report(label_analysis_request)
 
             if lines_relevant_to_diff and base_report:
@@ -217,7 +227,7 @@ def _get_requested_labels(self, label_analysis_request: LabelAnalysisRequest):
 
     @sentry_sdk.trace
     def _get_existing_labels(
-        self, report: Report, lines_relevant_to_diff
+        self, report: Report, lines_relevant_to_diff: LinesRelevantToChange
     ) -> Tuple[Set[str], Set[str], Set[str]]:
         all_report_labels = self.get_all_report_labels(report)
         executable_lines_labels, global_level_labels = self.get_executable_lines_labels(
@@ -403,7 +413,9 @@ def get_relevant_executable_lines(
         return static_analysis_comparison_service.get_base_lines_relevant_to_change()
 
     @sentry_sdk.trace
-    def get_executable_lines_labels(self, report: Report, executable_lines) -> set:
+    def get_executable_lines_labels(
+        self, report: Report, executable_lines: LinesRelevantToChange
+    ) -> set:
         if executable_lines["all"]:
             return (self.get_all_report_labels(report), set())
         full_sessions = set()
@@ -412,7 +424,7 @@ def get_executable_lines_labels(self, report: Report, executable_lines) -> set:
         # Prime piece of code to be rust-ifyied
         for name, file_executable_lines in executable_lines["files"].items():
             rf = report.get(name)
-            if rf:
+            if rf and file_executable_lines:
                 if file_executable_lines["all"]:
                     for line_number, line in rf.lines:
                         if line and line.datapoints:

tasks/tests/unit/test_label_analysis.py

@@ -400,8 +400,21 @@ def sample_report_with_labels():
             complexity=None,
         ),
     )
+    random_rf = ReportFile("path/from/randomfile_no_static_analysis.html")
+    random_rf.append(
+        1,
+        ReportLine.create(
+            coverage=1,
+            type=None,
+            sessions=[(LineSession(id=1, coverage=1))],
+            datapoints=None,
+            complexity=None,
+        ),
+    )
     r.append(first_rf)
     r.append(second_rf)
+    r.append(random_rf)
+
     return r
 
 
@@ -665,6 +678,55 @@ def test_get_executable_lines_labels_all_labels_in_one_file(sample_report_with_l
     )
 
 
+def test_get_executable_lines_labels_some_labels_in_one_file(sample_report_with_labels):
+    executable_lines = {
+        "all": False,
+        "files": {"source.py": {"all": False, "lines": set([5, 6])}},
+    }
+    task = LabelAnalysisRequestProcessingTask()
+    assert task.get_executable_lines_labels(
+        sample_report_with_labels, executable_lines
+    ) == (
+        {"apple", "label_one", "pineapple", "banana"},
+        set(),
+    )
+
+
+def test_get_executable_lines_labels_some_labels_in_one_file_with_globals(
+    sample_report_with_labels,
+):
+    executable_lines = {
+        "all": False,
+        "files": {"source.py": {"all": False, "lines": set([6, 8])}},
+    }
+    task = LabelAnalysisRequestProcessingTask()
+    assert task.get_executable_lines_labels(
+        sample_report_with_labels, executable_lines
+    ) == (
+        {"label_one", "pineapple", "banana", "orangejuice", "applejuice"},
+        {"applejuice", "justjuice", "orangejuice"},
+    )
+
+
+def test_get_executable_lines_labels_some_labels_in_one_file_other_null(
+    sample_report_with_labels,
+):
+    executable_lines = {
+        "all": False,
+        "files": {
+            "source.py": {"all": False, "lines": set([5, 6])},
+            "path/from/randomfile_no_static_analysis.html": None,
+        },
+    }
+    task = LabelAnalysisRequestProcessingTask()
+    assert task.get_executable_lines_labels(
+        sample_report_with_labels, executable_lines
+    ) == (
+        {"apple", "label_one", "pineapple", "banana"},
+        set(),
+    )
+
+
 def test_get_all_labels_one_session(sample_report_with_labels):
     task = LabelAnalysisRequestProcessingTask()
     assert task.get_labels_per_session(sample_report_with_labels, 1) == {