fix: 'always true' is clearer than 'never false'

CHANGES.rst

@@ -27,6 +27,9 @@ Unreleased
   hashes added to their names to ensure updated files are used instead of stale
   cached copies.
 
+- Missing branch coverage explanations that said "the condition was never
+  false" now read "was always true" because it's easier to understand.
+
 
 .. scriv-start-here
 

coverage/parser.py

@@ -1093,7 +1093,7 @@ def _handle__If(self, node: ast.If) -> set[ArcStart]:
         start = self.line_for_node(node.test)
         from_start = ArcStart(start, cause="the condition on line {lineno} was never true")
         exits = self.add_body_arcs(node.body, from_start=from_start)
-        from_start = ArcStart(start, cause="the condition on line {lineno} was never false")
+        from_start = ArcStart(start, cause="the condition on line {lineno} was always true")
         exits |= self.add_body_arcs(node.orelse, from_start=from_start)
         return exits
 
@@ -1287,7 +1287,7 @@ def _handle__While(self, node: ast.While) -> set[ArcStart]:
         my_block = self.block_stack.pop()
         assert isinstance(my_block, LoopBlock)
         exits.update(my_block.break_exits)
-        from_start = ArcStart(start, cause="the condition on line {lineno} was never false")
+        from_start = ArcStart(start, cause="the condition on line {lineno} was always true")
         if node.orelse:
             else_exits = self.add_body_arcs(node.orelse, from_start=from_start)
             exits |= else_exits

tests/gold/html/b_branch/b_py.html

@@ -67,7 +67,7 @@ <h2>
             <a id="nextFileLink" class="nav" href="index.html">&#xbb; next</a>
             &nbsp; &nbsp; &nbsp;
             <a class="nav" href="https://coverage.readthedocs.io/en/7.5.1a0.dev1">coverage.py v7.5.1a0.dev1</a>,
-            created at 2024-04-24 09:22 -0400
+            created at 2024-04-25 08:04 -0400
         </p>
         <aside class="hidden">
             <button type="button" class="button_next_chunk" data-shortcut="j"></button>
@@ -84,7 +84,7 @@ <h2>
 <main id="source">
     <p class="run"><span class="n"><a id="t1" href="#t1">1</a></span><span class="t"><span class="key">def</span> <span class="nam">one</span><span class="op">(</span><span class="nam">x</span><span class="op">)</span><span class="op">:</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t2" href="#t2">2</a></span><span class="t">    <span class="com"># This will be a branch that misses the else.</span>&nbsp;</span><span class="r"></span></p>
-    <p class="par run show_par"><span class="n"><a id="t3" href="#t3">3</a></span><span class="t">    <span class="key">if</span> <span class="nam">x</span> <span class="op">&lt;</span> <span class="num">2</span><span class="op">:</span>&nbsp;</span><span class="r"><span class="annotate short">3&#x202F;&#x219B;&#x202F;6</span><span class="annotate long">line 3 didn't jump to line 6, because the condition on line 3 was never false</span></span></p>
+    <p class="par run show_par"><span class="n"><a id="t3" href="#t3">3</a></span><span class="t">    <span class="key">if</span> <span class="nam">x</span> <span class="op">&lt;</span> <span class="num">2</span><span class="op">:</span>&nbsp;</span><span class="r"><span class="annotate short">3&#x202F;&#x219B;&#x202F;6</span><span class="annotate long">line 3 didn't jump to line 6, because the condition on line 3 was always true</span></span></p>
     <p class="run"><span class="n"><a id="t4" href="#t4">4</a></span><span class="t">        <span class="nam">a</span> <span class="op">=</span> <span class="num">3</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t5" href="#t5">5</a></span><span class="t">    <span class="key">else</span><span class="op">:</span>&nbsp;</span><span class="r"></span></p>
     <p class="mis show_mis"><span class="n"><a id="t6" href="#t6">6</a></span><span class="t">        <span class="nam">a</span> <span class="op">=</span> <span class="num">4</span>&nbsp;</span><span class="r"></span></p>
@@ -93,15 +93,15 @@ <h2>
     <p class="pln"><span class="n"><a id="t9" href="#t9">9</a></span><span class="t">&nbsp;</span><span class="r"></span></p>
     <p class="run"><span class="n"><a id="t10" href="#t10">10</a></span><span class="t"><span class="key">def</span> <span class="nam">two</span><span class="op">(</span><span class="nam">x</span><span class="op">)</span><span class="op">:</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t11" href="#t11">11</a></span><span class="t">    <span class="com"># A missed else that branches to "exit"</span>&nbsp;</span><span class="r"></span></p>
-    <p class="par run show_par"><span class="n"><a id="t12" href="#t12">12</a></span><span class="t">    <span class="key">if</span> <span class="nam">x</span><span class="op">:</span>&nbsp;</span><span class="r"><span class="annotate short">12&#x202F;&#x219B;&#x202F;exit</span><span class="annotate long">line 12 didn't return from function 'two', because the condition on line 12 was never false</span></span></p>
+    <p class="par run show_par"><span class="n"><a id="t12" href="#t12">12</a></span><span class="t">    <span class="key">if</span> <span class="nam">x</span><span class="op">:</span>&nbsp;</span><span class="r"><span class="annotate short">12&#x202F;&#x219B;&#x202F;exit</span><span class="annotate long">line 12 didn't return from function 'two', because the condition on line 12 was always true</span></span></p>
     <p class="run"><span class="n"><a id="t13" href="#t13">13</a></span><span class="t">        <span class="nam">a</span> <span class="op">=</span> <span class="num">5</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t14" href="#t14">14</a></span><span class="t">&nbsp;</span><span class="r"></span></p>
     <p class="run"><span class="n"><a id="t15" href="#t15">15</a></span><span class="t"><span class="nam">two</span><span class="op">(</span><span class="num">1</span><span class="op">)</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t16" href="#t16">16</a></span><span class="t">&nbsp;</span><span class="r"></span></p>
     <p class="run"><span class="n"><a id="t17" href="#t17">17</a></span><span class="t"><span class="key">def</span> <span class="nam">three</span><span class="op">(</span><span class="op">)</span><span class="op">:</span>&nbsp;</span><span class="r"></span></p>
     <p class="run"><span class="n"><a id="t18" href="#t18">18</a></span><span class="t">    <span class="key">try</span><span class="op">:</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t19" href="#t19">19</a></span><span class="t">        <span class="com"># This if has two branches, *neither* one taken.</span>&nbsp;</span><span class="r"></span></p>
-    <p class="par run show_par"><span class="n"><a id="t20" href="#t20">20</a></span><span class="t">        <span class="key">if</span> <span class="nam">name_error_this_variable_doesnt_exist</span><span class="op">:</span>&nbsp;</span><span class="r"><span class="annotate short">20&#x202F;&#x219B;&#x202F;21,&nbsp;&nbsp; 20&#x202F;&#x219B;&#x202F;23</span><span class="annotate long">2 missed branches: 1) line 20 didn't jump to line 21, because the condition on line 20 was never true, 2) line 20 didn't jump to line 23, because the condition on line 20 was never false</span></span></p>
+    <p class="par run show_par"><span class="n"><a id="t20" href="#t20">20</a></span><span class="t">        <span class="key">if</span> <span class="nam">name_error_this_variable_doesnt_exist</span><span class="op">:</span>&nbsp;</span><span class="r"><span class="annotate short">20&#x202F;&#x219B;&#x202F;21,&nbsp;&nbsp; 20&#x202F;&#x219B;&#x202F;23</span><span class="annotate long">2 missed branches: 1) line 20 didn't jump to line 21, because the condition on line 20 was never true, 2) line 20 didn't jump to line 23, because the condition on line 20 was always true</span></span></p>
     <p class="mis show_mis"><span class="n"><a id="t21" href="#t21">21</a></span><span class="t">            <span class="nam">a</span> <span class="op">=</span> <span class="num">1</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t22" href="#t22">22</a></span><span class="t">        <span class="key">else</span><span class="op">:</span>&nbsp;</span><span class="r"></span></p>
     <p class="mis show_mis"><span class="n"><a id="t23" href="#t23">23</a></span><span class="t">            <span class="nam">a</span> <span class="op">=</span> <span class="num">2</span>&nbsp;</span><span class="r"></span></p>
@@ -118,7 +118,7 @@ <h2>
             <a class="nav" href="index.html">&#xbb; next</a>
             &nbsp; &nbsp; &nbsp;
             <a class="nav" href="https://coverage.readthedocs.io/en/7.5.1a0.dev1">coverage.py v7.5.1a0.dev1</a>,
-            created at 2024-04-24 09:22 -0400
+            created at 2024-04-25 08:04 -0400
         </p>
     </div>
 </footer>

tests/gold/html/partial/partial_py.html

@@ -67,7 +67,7 @@ <h2>
             <a id="nextFileLink" class="nav" href="index.html">&#xbb; next</a>
             &nbsp; &nbsp; &nbsp;
             <a class="nav" href="https://coverage.readthedocs.io/en/7.5.1a0.dev1">coverage.py v7.5.1a0.dev1</a>,
-            created at 2024-04-24 10:14 -0400
+            created at 2024-04-25 08:07 -0400
         </p>
         <aside class="hidden">
             <button type="button" class="button_next_chunk" data-shortcut="j"></button>
@@ -85,7 +85,7 @@ <h2>
     <p class="pln"><span class="n"><a id="t1" href="#t1">1</a></span><span class="t"><span class="com"># partial branches and excluded lines</span>&nbsp;</span><span class="r"></span></p>
     <p class="run"><span class="n"><a id="t2" href="#t2">2</a></span><span class="t"><span class="nam">a</span> <span class="op">=</span> <span class="num">2</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t3" href="#t3">3</a></span><span class="t">&nbsp;</span><span class="r"></span></p>
-    <p class="par run show_par"><span class="n"><a id="t4" href="#t4">4</a></span><span class="t"><span class="key">while</span> <span class="str">"no peephole"</span><span class="op">.</span><span class="nam">upper</span><span class="op">(</span><span class="op">)</span><span class="op">:</span>        <span class="com"># t4</span>&nbsp;</span><span class="r"><span class="annotate short">4&#x202F;&#x219B;&#x202F;7</span><span class="annotate long">line 4 didn't jump to line 7, because the condition on line 4 was never false</span></span></p>
+    <p class="par run show_par"><span class="n"><a id="t4" href="#t4">4</a></span><span class="t"><span class="key">while</span> <span class="str">"no peephole"</span><span class="op">.</span><span class="nam">upper</span><span class="op">(</span><span class="op">)</span><span class="op">:</span>        <span class="com"># t4</span>&nbsp;</span><span class="r"><span class="annotate short">4&#x202F;&#x219B;&#x202F;7</span><span class="annotate long">line 4 didn't jump to line 7, because the condition on line 4 was always true</span></span></p>
     <p class="run"><span class="n"><a id="t5" href="#t5">5</a></span><span class="t">    <span class="key">break</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t6" href="#t6">6</a></span><span class="t">&nbsp;</span><span class="r"></span></p>
     <p class="run"><span class="n"><a id="t7" href="#t7">7</a></span><span class="t"><span class="key">while</span> <span class="nam">a</span><span class="op">:</span>        <span class="com"># pragma: no branch</span>&nbsp;</span><span class="r"></span></p>
@@ -108,7 +108,7 @@ <h2>
             <a class="nav" href="index.html">&#xbb; next</a>
             &nbsp; &nbsp; &nbsp;
             <a class="nav" href="https://coverage.readthedocs.io/en/7.5.1a0.dev1">coverage.py v7.5.1a0.dev1</a>,
-            created at 2024-04-24 10:14 -0400
+            created at 2024-04-25 08:07 -0400
         </p>
     </div>
 </footer>

tests/gold/html/partial_626/partial_py.html

@@ -67,7 +67,7 @@ <h2>
             <a id="nextFileLink" class="nav" href="index.html">&#xbb; next</a>
             &nbsp; &nbsp; &nbsp;
             <a class="nav" href="https://coverage.readthedocs.io/en/7.5.1a0.dev1">coverage.py v7.5.1a0.dev1</a>,
-            created at 2024-04-24 09:22 -0400
+            created at 2024-04-25 08:04 -0400
         </p>
         <aside class="hidden">
             <button type="button" class="button_next_chunk" data-shortcut="j"></button>
@@ -85,7 +85,7 @@ <h2>
     <p class="pln"><span class="n"><a id="t1" href="#t1">1</a></span><span class="t"><span class="com"># partial branches and excluded lines</span>&nbsp;</span><span class="r"></span></p>
     <p class="run"><span class="n"><a id="t2" href="#t2">2</a></span><span class="t"><span class="nam">a</span> <span class="op">=</span> <span class="num">2</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t3" href="#t3">3</a></span><span class="t">&nbsp;</span><span class="r"></span></p>
-    <p class="par run show_par"><span class="n"><a id="t4" href="#t4">4</a></span><span class="t"><span class="key">while</span> <span class="str">"no peephole"</span><span class="op">.</span><span class="nam">upper</span><span class="op">(</span><span class="op">)</span><span class="op">:</span>        <span class="com"># t4</span>&nbsp;</span><span class="r"><span class="annotate short">4&#x202F;&#x219B;&#x202F;7</span><span class="annotate long">line 4 didn't jump to line 7, because the condition on line 4 was never false</span></span></p>
+    <p class="par run show_par"><span class="n"><a id="t4" href="#t4">4</a></span><span class="t"><span class="key">while</span> <span class="str">"no peephole"</span><span class="op">.</span><span class="nam">upper</span><span class="op">(</span><span class="op">)</span><span class="op">:</span>        <span class="com"># t4</span>&nbsp;</span><span class="r"><span class="annotate short">4&#x202F;&#x219B;&#x202F;7</span><span class="annotate long">line 4 didn't jump to line 7, because the condition on line 4 was always true</span></span></p>
     <p class="run"><span class="n"><a id="t5" href="#t5">5</a></span><span class="t">    <span class="key">break</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t6" href="#t6">6</a></span><span class="t">&nbsp;</span><span class="r"></span></p>
     <p class="run"><span class="n"><a id="t7" href="#t7">7</a></span><span class="t"><span class="key">while</span> <span class="nam">a</span><span class="op">:</span>        <span class="com"># pragma: no branch</span>&nbsp;</span><span class="r"></span></p>
@@ -94,7 +94,7 @@ <h2>
     <p class="run"><span class="n"><a id="t10" href="#t10">10</a></span><span class="t"><span class="key">if</span> <span class="num">0</span><span class="op">:</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t11" href="#t11">11</a></span><span class="t">    <span class="nam">never_happen</span><span class="op">(</span><span class="op">)</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t12" href="#t12">12</a></span><span class="t">&nbsp;</span><span class="r"></span></p>
-    <p class="par run show_par"><span class="n"><a id="t13" href="#t13">13</a></span><span class="t"><span class="key">if</span> <span class="num">13</span><span class="op">:</span>&nbsp;</span><span class="r"><span class="annotate short">13&#x202F;&#x219B;&#x202F;16</span><span class="annotate long">line 13 didn't jump to line 16, because the condition on line 13 was never false</span></span></p>
+    <p class="par run show_par"><span class="n"><a id="t13" href="#t13">13</a></span><span class="t"><span class="key">if</span> <span class="num">13</span><span class="op">:</span>&nbsp;</span><span class="r"><span class="annotate short">13&#x202F;&#x219B;&#x202F;16</span><span class="annotate long">line 13 didn't jump to line 16, because the condition on line 13 was always true</span></span></p>
     <p class="run"><span class="n"><a id="t14" href="#t14">14</a></span><span class="t">    <span class="nam">a</span> <span class="op">=</span> <span class="num">14</span>&nbsp;</span><span class="r"></span></p>
     <p class="pln"><span class="n"><a id="t15" href="#t15">15</a></span><span class="t">&nbsp;</span><span class="r"></span></p>
     <p class="run"><span class="n"><a id="t16" href="#t16">16</a></span><span class="t"><span class="key">if</span> <span class="nam">a</span> <span class="op">==</span> <span class="num">16</span><span class="op">:</span>&nbsp;</span><span class="r"></span></p>
@@ -108,7 +108,7 @@ <h2>
             <a class="nav" href="index.html">&#xbb; next</a>
             &nbsp; &nbsp; &nbsp;
             <a class="nav" href="https://coverage.readthedocs.io/en/7.5.1a0.dev1">coverage.py v7.5.1a0.dev1</a>,
-            created at 2024-04-24 09:22 -0400
+            created at 2024-04-25 08:04 -0400
         </p>
     </div>
 </footer>

tests/test_html.py

@@ -813,17 +813,17 @@ def three():
 
             ('<span class="annotate short">3&#x202F;&#x219B;&#x202F;6</span>' +
              '<span class="annotate long">line 3 didn\'t jump to line 6, ' +
-                            'because the condition on line 3 was never false</span>'),
+                            'because the condition on line 3 was always true</span>'),
             ('<span class="annotate short">12&#x202F;&#x219B;&#x202F;exit</span>' +
              '<span class="annotate long">line 12 didn\'t return from function \'two\', ' +
-                            'because the condition on line 12 was never false</span>'),
+                            'because the condition on line 12 was always true</span>'),
             ('<span class="annotate short">20&#x202F;&#x219B;&#x202F;21,&nbsp;&nbsp; ' +
                             '20&#x202F;&#x219B;&#x202F;23</span>' +
              '<span class="annotate long">2 missed branches: ' +
                             '1) line 20 didn\'t jump to line 21, ' +
                                 'because the condition on line 20 was never true, ' +
                             '2) line 20 didn\'t jump to line 23, ' +
-                                'because the condition on line 20 was never false</span>'),
+                                'because the condition on line 20 was always true</span>'),
         )
         contains(
             "out/b_branch/index.html",

tests/test_parser.py

@@ -759,7 +759,7 @@ def func10():
             """)
         expected = "line 1 didn't jump to line 2, because the condition on line 1 was never true"
         assert expected == parser.missing_arc_description(1, 2)
-        expected = "line 1 didn't jump to line 3, because the condition on line 1 was never false"
+        expected = "line 1 didn't jump to line 3, because the condition on line 1 was always true"
         assert expected == parser.missing_arc_description(1, 3)
         expected = (
             "line 6 didn't return from function 'func5', " +
@@ -772,7 +772,7 @@ def func10():
         assert expected == parser.missing_arc_description(11, 12)
         expected = (
             "line 11 didn't jump to line 13, " +
-            "because the condition on line 11 was never false"
+            "because the condition on line 11 was always true"
         )
         assert expected == parser.missing_arc_description(11, 13)