refactor: use sets to collect data

Coverage.py predates sets as a built-in data structure, so the file data
collection has long been dicts with None as the values.  Sets are
available to us now (since Python 2.4 in 2004, which coverage.py dropped
support for in 2014!), we use sets.

1 files changed, 15 insertions, 15 deletions

diff --git a/coverage/pytracer.py b/coverage/pytracer.py
index 540df68c..d4a0b748 100644
--- a/coverage/pytracer.py
+++ b/coverage/pytracer.py
@@ -48,7 +48,7 @@ class PyTracer:
         # The threading module to use, if any.
         self.threading = None
 
-        self.cur_file_dict = None
+        self.cur_file_data = None
         self.last_line = 0          # int, but uninitialized.
         self.cur_file_name = None
         self.context = None
@@ -113,7 +113,7 @@ class PyTracer:
                     self.log(">", f.f_code.co_filename, f.f_lineno, f.f_code.co_name, f.f_trace)
                     f = f.f_back
             sys.settrace(None)
-            self.cur_file_dict, self.cur_file_name, self.last_line, self.started_context = (
+            self.cur_file_data, self.cur_file_name, self.last_line, self.started_context = (
                 self.data_stack.pop()
             )
             return None
@@ -121,10 +121,10 @@ class PyTracer:
         if self.last_exc_back:
             if frame == self.last_exc_back:
                 # Someone forgot a return event.
-                if self.trace_arcs and self.cur_file_dict:
+                if self.trace_arcs and self.cur_file_data:
                     pair = (self.last_line, -self.last_exc_firstlineno)
-                    self.cur_file_dict[pair] = None
-                self.cur_file_dict, self.cur_file_name, self.last_line, self.started_context = (
+                    self.cur_file_data.add(pair)
+                self.cur_file_data, self.cur_file_name, self.last_line, self.started_context = (
                     self.data_stack.pop()
                 )
             self.last_exc_back = None
@@ -150,7 +150,7 @@ class PyTracer:
             self._activity = True
             self.data_stack.append(
                 (
-                    self.cur_file_dict,
+                    self.cur_file_data,
                     self.cur_file_name,
                     self.last_line,
                     self.started_context,
@@ -163,12 +163,12 @@ class PyTracer:
                 disp = self.should_trace(filename, frame)
                 self.should_trace_cache[filename] = disp
 
-            self.cur_file_dict = None
+            self.cur_file_data = None
             if disp.trace:
                 tracename = disp.source_filename
                 if tracename not in self.data:
-                    self.data[tracename] = {}
-                self.cur_file_dict = self.data[tracename]
+                    self.data[tracename] = set()
+                self.cur_file_data = self.data[tracename]
             # The call event is really a "start frame" event, and happens for
             # function calls and re-entering generators.  The f_lasti field is
             # -1 for calls, and a real offset for generators.  Use <0 as the
@@ -179,25 +179,25 @@ class PyTracer:
                 self.last_line = frame.f_lineno
         elif event == 'line':
             # Record an executed line.
-            if self.cur_file_dict is not None:
+            if self.cur_file_data is not None:
                 lineno = frame.f_lineno
 
                 if self.trace_arcs:
-                    self.cur_file_dict[(self.last_line, lineno)] = None
+                    self.cur_file_data.add((self.last_line, lineno))
                 else:
-                    self.cur_file_dict[lineno] = None
+                    self.cur_file_data.add(lineno)
                 self.last_line = lineno
         elif event == 'return':
-            if self.trace_arcs and self.cur_file_dict:
+            if self.trace_arcs and self.cur_file_data:
                 # Record an arc leaving the function, but beware that a
                 # "return" event might just mean yielding from a generator.
                 # Jython seems to have an empty co_code, so just assume return.
                 code = frame.f_code.co_code
                 if (not code) or code[frame.f_lasti] != YIELD_VALUE:
                     first = frame.f_code.co_firstlineno
-                    self.cur_file_dict[(self.last_line, -first)] = None
+                    self.cur_file_data.add((self.last_line, -first))
             # Leaving this function, pop the filename stack.
-            self.cur_file_dict, self.cur_file_name, self.last_line, self.started_context = (
+            self.cur_file_data, self.cur_file_name, self.last_line, self.started_context = (
                 self.data_stack.pop()
             )
             # Leaving a context?