Make sure check_include isn't called more than once per file.

3 files changed, 30 insertions, 1 deletions

diff --git a/coverage/control.py b/coverage/control.py
index cb614d56..7e338625 100644
--- a/coverage/control.py
+++ b/coverage/control.py
@@ -936,6 +936,8 @@ class FileDisposition(object):
         """Produce a debugging message explaining the outcome."""
         if self.trace:
             msg = "Tracing %r" % (self.original_filename,)
+            if self.file_tracer:
+                msg += ": will be traced by %r" % self.file_tracer
         else:
             msg = "Not tracing %r: %s" % (self.original_filename, self.reason)
         return msg
diff --git a/coverage/pytracer.py b/coverage/pytracer.py
index 98b52028..16a51c2b 100644
--- a/coverage/pytracer.py
+++ b/coverage/pytracer.py
@@ -87,7 +87,11 @@ class PyTracer(object):
                 if disp.file_tracer and disp.has_dynamic_filename:
                     tracename = disp.file_tracer.dynamic_source_filename(tracename, frame)
                     if tracename:
-                        if not self.check_include(tracename, frame):
+                        included = self.should_trace_cache.get(tracename)
+                        if included is None:
+                            included = self.check_include(tracename, frame)
+                            self.should_trace_cache[tracename] = included
+                        if not included:
                             tracename = None
             else:
                 tracename = None
diff --git a/tests/test_plugins.py b/tests/test_plugins.py
index b94d0776..874cf521 100644
--- a/tests/test_plugins.py
+++ b/tests/test_plugins.py
@@ -160,6 +160,7 @@ if not C_TRACER:
                 """)
 
             cov = coverage.Coverage()
+            snoop_on_callbacks(cov)
             cov.config["run:plugins"] = ["tests.plugin1"]
 
             # Import the python file, executing it.
@@ -192,12 +193,16 @@ if not C_TRACER:
                 from render import helper, render
 
                 assert render("foo_7.html", 4) == "[foo_7.html @ 4]"
+                # Render foo_7.html again to trigger the callback snoopers.
+                render("foo_7.html", 4)
+
                 assert helper(42) == 43
                 assert render("bar_4.html", 2) == "[bar_4.html @ 2]"
                 assert helper(76) == 77
                 """)
 
             cov = coverage.Coverage()
+            snoop_on_callbacks(cov)
             cov.config["run:plugins"] = ["tests.plugin2"]
 
             self.start_import_stop(cov, "caller")
@@ -211,3 +216,21 @@ if not C_TRACER:
             _, statements, missing, _ = cov.analysis("bar_4.html")
             self.assertEqual(statements, [1,2,3,4])
             self.assertEqual(missing, [1,4])
+
+
+def snoop_on_callbacks(cov):
+    cov_should_trace = cov._should_trace
+    should_trace_filenames = set()
+    def snoop_should_trace(filename, frame):
+        assert filename not in should_trace_filenames
+        should_trace_filenames.add(filename)
+        return cov_should_trace(filename, frame)
+    cov._should_trace = snoop_should_trace
+
+    cov_check_include = cov._check_include_omit_etc
+    check_include_filenames = set()
+    def snoop_check_include_filenames(filename, frame):
+        assert filename not in check_include_filenames
+        check_include_filenames.add(filename)
+        return cov_check_include(filename, frame)
+    cov._check_include_omit_etc = snoop_check_include_filenames