fix: don't report branches to missing lines. #1065

Fixes: #1065
Fixes: #955

CHANGES.rst

@@ -29,6 +29,12 @@ Unreleased
   they have been combined.  This was requested in `issue 1108`_ and implemented
   in `pull request 1110`_.  Thanks, Éric Larivière.
 
+- When reporting missing branches in ``coverage report``, branches aren't
+  reported that jump to missing lines.  This adds to the long-standing behavior
+  of not reporting branches from missing lines.  Now branches are only reported
+  if both the source and destination lines are executed.  Closes both `issue
+  1065`_ and `issue 955`_.
+
 - Minor improvements to the HTML report:
 
   - The state of the line visibility selector buttons is saved in local storage
@@ -41,6 +47,8 @@ Unreleased
   will be more likely to understand what's happening, closing `issue 803`_.
 
 .. _issue 803: https://github.com/nedbat/coveragepy/issues/803
+.. _issue 955: https://github.com/nedbat/coveragepy/issues/955
+.. _issue 1065: https://github.com/nedbat/coveragepy/issues/1065
 .. _issue 1108: https://github.com/nedbat/coveragepy/issues/1108
 .. _pull request 1110: https://github.com/nedbat/coveragepy/pull/1110
 .. _issue 1123: https://github.com/nedbat/coveragepy/issues/1123

coverage/results.py

@@ -312,7 +312,7 @@ def format_lines(statements, lines, arcs=None):
         line_exits = sorted(arcs)
         for line, exits in line_exits:
             for ex in sorted(exits):
-                if line not in lines:
+                if line not in lines and ex not in lines:
                     dest = (ex if ex > 0 else "exit")
                     line_items.append((line, "%d->%s" % (line, dest)))
 

tests/test_coverage.py

@@ -732,7 +732,7 @@ def test_elif(self):
                 z = 7
             assert x == 3
             """,
-            [1,2,3,4,5,7,8], "4-7", report="7 3 4 1 45% 2->4, 4-7",
+            [1,2,3,4,5,7,8], "4-7", report="7 3 4 1 45% 4-7",
         )
         self.check_coverage("""\
             a = 1; b = 2; c = 3;
@@ -744,7 +744,7 @@ def test_elif(self):
                 z = 7
             assert y == 5
             """,
-            [1,2,3,4,5,7,8], "3, 7", report="7 2 4 2 64% 2->3, 3, 4->7, 7",
+            [1,2,3,4,5,7,8], "3, 7", report="7 2 4 2 64% 3, 7",
         )
         self.check_coverage("""\
             a = 1; b = 2; c = 3;
@@ -756,7 +756,7 @@ def test_elif(self):
                 z = 7
             assert z == 7
             """,
-            [1,2,3,4,5,7,8], "3, 5", report="7 2 4 2 64% 2->3, 3, 4->5, 5",
+            [1,2,3,4,5,7,8], "3, 5", report="7 2 4 2 64% 3, 5",
         )
 
     def test_elif_no_else(self):
@@ -768,7 +768,7 @@ def test_elif_no_else(self):
                 y = 5
             assert x == 3
             """,
-            [1,2,3,4,5,6], "4-5", report="6 2 4 1 50% 2->4, 4-5",
+            [1,2,3,4,5,6], "4-5", report="6 2 4 1 50% 4-5",
         )
         self.check_coverage("""\
             a = 1; b = 2; c = 3;
@@ -778,7 +778,7 @@ def test_elif_no_else(self):
                 y = 5
             assert y == 5
             """,
-            [1,2,3,4,5,6], "3", report="6 1 4 2 70% 2->3, 3, 4->6",
+            [1,2,3,4,5,6], "3", report="6 1 4 2 70% 3, 4->6",
         )
 
     def test_elif_bizarre(self):

tests/test_summary.py

@@ -280,7 +280,7 @@ def branch(x, y, z):
             'Name          Stmts   Miss Branch BrPart  Cover   Missing',
             '---------------------------------------------------------',
             'main.py           1      0      0      0   100%',
-            'mybranch.py      10      2      8      3    61%   2->4, 4->6, 6->7, 7-8',
+            'mybranch.py      10      2      8      3    61%   2->4, 4->6, 7-8',
             '---------------------------------------------------------',
             'TOTAL            11      2      8      3    63%',
         ]