Fix significant bug with storing composed matchers

Given that in the 2 or so years that matchers are thing nobody complained,
it seems that people do not actually write this sort of code, and the
possibility will be removed in v3. However, to avoid correctness bugs,
we will have to support this weird code in v2.

docs/deprecations.md

@@ -9,6 +9,35 @@ either of these is a breaking change, and thus will not happen until
 at least the next major release.
 
 
+### Composing lvalues of already composed matchers
+
+Because a significant bug in this use case has persisted for 2+ years
+without a bug report, and to simplify the implementation, code that
+composes lvalues of composed matchers will not compile. That is,
+this code will no longer work:
+
+```cpp
+            auto m1 = Contains("string");
+            auto m2 = Contains("random");
+            auto composed1 = m1 || m2;
+            auto m3 = Contains("different");
+            auto composed2 = composed1 || m3;
+            REQUIRE_THAT(foo(), !composed1);
+            REQUIRE_THAT(foo(), composed2);
+```
+
+Instead you will have to write this:
+
+```cpp
+            auto m1 = Contains("string");
+            auto m2 = Contains("random");
+            auto m3 = Contains("different");
+            REQUIRE_THAT(foo(), !(m1 || m2));
+            REQUIRE_THAT(foo(), m1 || m2 || m3);
+```
+
+
+
 ## Planned changes
 
 ### `CHECKED_IF` and `CHECKED_ELSE`

src/catch2/catch_matchers.h

@@ -91,9 +91,10 @@ namespace Matchers {
                 return description;
             }
 
-            MatchAllOf<ArgT>& operator && ( MatcherBase<ArgT> const& other ) {
+            MatchAllOf<ArgT> operator && ( MatcherBase<ArgT> const& other ) {
-                m_matchers.push_back( &other );
+                auto copy(*this);
-                return *this;
+                copy.m_matchers.push_back( &other );
+                return copy;
             }
 
             std::vector<MatcherBase<ArgT> const*> m_matchers;
@@ -124,9 +125,10 @@ namespace Matchers {
                 return description;
             }
 
-            MatchAnyOf<ArgT>& operator || ( MatcherBase<ArgT> const& other ) {
+            MatchAnyOf<ArgT> operator || ( MatcherBase<ArgT> const& other ) {
-                m_matchers.push_back( &other );
+                auto copy(*this);
-                return *this;
+                copy.m_matchers.push_back( &other );
+                return copy;
             }
 
             std::vector<MatcherBase<ArgT> const*> m_matchers;

tests/SelfTest/Baselines/automake.sw.approved.txt

@@ -99,6 +99,7 @@ Nor would this
 :test-result: PASS Comparisons between ints where one side is computed
 :test-result: PASS Comparisons between unsigned ints and negative signed ints match c++ standard behaviour
 :test-result: PASS Comparisons with int literals don't warn when mixing signed/ unsigned
+:test-result: PASS Composed matchers are distinct
 :test-result: FAIL Contains string matcher
 :test-result: PASS Copy and then generate a range
 :test-result: FAIL Custom exceptions can be translated when testing for nothrow

tests/SelfTest/Baselines/compact.sw.approved.txt

@@ -344,6 +344,8 @@ Condition.tests.cpp:<line number>: passed: 4 == ul for: 4 == 4
 Condition.tests.cpp:<line number>: passed: 5 == c for: 5 == 5
 Condition.tests.cpp:<line number>: passed: 6 == uc for: 6 == 6
 Condition.tests.cpp:<line number>: passed: (std::numeric_limits<uint32_t>::max)() > ul for: 4294967295 (0x<hex digits>) > 4
+Matchers.tests.cpp:<line number>: passed: testStringForMatching2(), !composed1 for: "some completely different text that contains one common word" not ( contains: "string" or contains: "random" )
+Matchers.tests.cpp:<line number>: passed: testStringForMatching2(), composed2 for: "some completely different text that contains one common word" ( contains: "string" or contains: "random" or contains: "different" )
 Matchers.tests.cpp:<line number>: failed: testStringForMatching(), Contains("not there", Catch::CaseSensitive::No) for: "this string contains 'abc' as a substring" contains: "not there" (case insensitive)
 Matchers.tests.cpp:<line number>: failed: testStringForMatching(), Contains("STRING") for: "this string contains 'abc' as a substring" contains: "STRING"
 Generators.tests.cpp:<line number>: passed: elem % 2 == 1 for: 1 == 1

tests/SelfTest/Baselines/console.std.approved.txt

@@ -1380,6 +1380,6 @@ due to unexpected exception with message:
   Why would you throw a std::string?
 
 ===============================================================================
-test cases:  328 |  254 passed |  70 failed |  4 failed as expected
+test cases:  329 |  255 passed |  70 failed |  4 failed as expected
-assertions: 1829 | 1677 passed | 131 failed | 21 failed as expected
+assertions: 1831 | 1679 passed | 131 failed | 21 failed as expected
 

tests/SelfTest/Baselines/console.sw.approved.txt

@@ -2610,6 +2610,24 @@ Condition.tests.cpp:<line number>: PASSED:
 with expansion:
   4294967295 (0x<hex digits>) > 4
 
+-------------------------------------------------------------------------------
+Composed matchers are distinct
+-------------------------------------------------------------------------------
+Matchers.tests.cpp:<line number>
+...............................................................................
+
+Matchers.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( testStringForMatching2(), !composed1 )
+with expansion:
+  "some completely different text that contains one common word" not (
+  contains: "string" or contains: "random" )
+
+Matchers.tests.cpp:<line number>: PASSED:
+  REQUIRE_THAT( testStringForMatching2(), composed2 )
+with expansion:
+  "some completely different text that contains one common word" ( contains:
+  "string" or contains: "random" or contains: "different" )
+
 -------------------------------------------------------------------------------
 Contains string matcher
 -------------------------------------------------------------------------------
@@ -14300,6 +14318,6 @@ Misc.tests.cpp:<line number>
 Misc.tests.cpp:<line number>: PASSED:
 
 ===============================================================================
-test cases:  328 |  238 passed |  86 failed |  4 failed as expected
+test cases:  329 |  239 passed |  86 failed |  4 failed as expected
-assertions: 1846 | 1677 passed | 148 failed | 21 failed as expected
+assertions: 1848 | 1679 passed | 148 failed | 21 failed as expected
 

tests/SelfTest/Baselines/junit.sw.approved.txt

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <testsuitesloose text artifact
 >
-  <testsuite name="<exe-name>" errors="17" failures="132" tests="1847" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
+  <testsuite name="<exe-name>" errors="17" failures="132" tests="1849" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
     <properties>
       <property name="filters" value="~[!nonportable]~[!benchmark]~[approvals] *"/>
       <property name="random-seed" value="1"/>
@@ -364,6 +364,7 @@ Exception.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="Comparisons between ints where one side is computed" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="Comparisons between unsigned ints and negative signed ints match c++ standard behaviour" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="Comparisons with int literals don't warn when mixing signed/ unsigned" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Composed matchers are distinct" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="Contains string matcher" time="{duration}">
       <failure message="testStringForMatching(), Contains(&quot;not there&quot;, Catch::CaseSensitive::No)" type="CHECK_THAT">
 FAILED:

tests/SelfTest/Baselines/sonarqube.sw.approved.txt

@@ -923,6 +923,7 @@ Exception.tests.cpp:<line number>
     <testCase name="Combining only templated matchers" duration="{duration}"/>
     <testCase name="Combining templated and concrete matchers" duration="{duration}"/>
     <testCase name="Combining templated matchers" duration="{duration}"/>
+    <testCase name="Composed matchers are distinct" duration="{duration}"/>
     <testCase name="Contains string matcher" duration="{duration}">
       <failure message="CHECK_THAT(testStringForMatching(), Contains(&quot;not there&quot;, Catch::CaseSensitive::No))">
 FAILED:

tests/SelfTest/Baselines/tap.sw.approved.txt

@@ -686,6 +686,10 @@ ok {test-number} - 5 == c for: 5 == 5
 ok {test-number} - 6 == uc for: 6 == 6
 # Comparisons with int literals don't warn when mixing signed/ unsigned
 ok {test-number} - (std::numeric_limits<uint32_t>::max)() > ul for: 4294967295 (0x<hex digits>) > 4
+# Composed matchers are distinct
+ok {test-number} - testStringForMatching2(), !composed1 for: "some completely different text that contains one common word" not ( contains: "string" or contains: "random" )
+# Composed matchers are distinct
+ok {test-number} - testStringForMatching2(), composed2 for: "some completely different text that contains one common word" ( contains: "string" or contains: "random" or contains: "different" )
 # Contains string matcher
 not ok {test-number} - testStringForMatching(), Contains("not there", Catch::CaseSensitive::No) for: "this string contains 'abc' as a substring" contains: "not there" (case insensitive)
 # Contains string matcher
@@ -3684,5 +3688,5 @@ ok {test-number} - q3 == 23. for: 23.0 == 23.0
 ok {test-number} -
 # xmlentitycheck
 ok {test-number} -
-1..1838
+1..1840
 

tests/SelfTest/Baselines/teamcity.sw.approved.txt

@@ -231,6 +231,8 @@ Exception.tests.cpp:<line number>|nunexpected exception with message:|n  "unexpe
 ##teamcity[testFinished name='Comparisons between unsigned ints and negative signed ints match c++ standard behaviour' duration="{duration}"]
 ##teamcity[testStarted name='Comparisons with int literals don|'t warn when mixing signed/ unsigned']
 ##teamcity[testFinished name='Comparisons with int literals don|'t warn when mixing signed/ unsigned' duration="{duration}"]
+##teamcity[testStarted name='Composed matchers are distinct']
+##teamcity[testFinished name='Composed matchers are distinct' duration="{duration}"]
 ##teamcity[testStarted name='Contains string matcher']
 Matchers.tests.cpp:<line number>|nexpression failed|n  CHECK_THAT( testStringForMatching(), Contains("not there", Catch::CaseSensitive::No) )|nwith expansion:|n  "this string contains |'abc|' as a substring" contains: "not there" (case insensitive)|n']
 Matchers.tests.cpp:<line number>|nexpression failed|n  CHECK_THAT( testStringForMatching(), Contains("STRING") )|nwith expansion:|n  "this string contains |'abc|' as a substring" contains: "STRING"|n']

tests/SelfTest/Baselines/xml.sw.approved.txt

@@ -3011,6 +3011,25 @@ Nor would this
       </Expression>
       <OverallResult success="true"/>
     </TestCase>
+    <TestCase name="Composed matchers are distinct" tags="[composed][matchers]" filename="tests/<exe-name>/UsageTests/Matchers.tests.cpp" >
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/UsageTests/Matchers.tests.cpp" >
+        <Original>
+          testStringForMatching2(), !composed1
+        </Original>
+        <Expanded>
+          "some completely different text that contains one common word" not ( contains: "string" or contains: "random" )
+        </Expanded>
+      </Expression>
+      <Expression success="true" type="REQUIRE_THAT" filename="tests/<exe-name>/UsageTests/Matchers.tests.cpp" >
+        <Original>
+          testStringForMatching2(), composed2
+        </Original>
+        <Expanded>
+          "some completely different text that contains one common word" ( contains: "string" or contains: "random" or contains: "different" )
+        </Expanded>
+      </Expression>
+      <OverallResult success="true"/>
+    </TestCase>
     <TestCase name="Contains string matcher" tags="[.][failing][matchers]" filename="tests/<exe-name>/UsageTests/Matchers.tests.cpp" >
       <Expression success="false" type="CHECK_THAT" filename="tests/<exe-name>/UsageTests/Matchers.tests.cpp" >
         <Original>
@@ -17139,7 +17158,7 @@ loose text artifact
       </Section>
       <OverallResult success="true"/>
     </TestCase>
-    <OverallResults successes="1677" failures="149" expectedFailures="21"/>
+    <OverallResults successes="1679" failures="149" expectedFailures="21"/>
   </Group>
-  <OverallResults successes="1677" failures="148" expectedFailures="21"/>
+  <OverallResults successes="1679" failures="148" expectedFailures="21"/>
 </Catch>

tests/SelfTest/UsageTests/Matchers.tests.cpp

@@ -556,6 +556,16 @@ namespace { namespace MatchersTests {
             REQUIRE_THROWS_MATCHES(throwsSpecialException(2), SpecialException,  Message("SpecialException::what"));
         }
 
+        TEST_CASE("Composed matchers are distinct", "[matchers][composed]") {
+            auto m1 = Contains("string");
+            auto m2 = Contains("random");
+            auto composed1 = m1 || m2;
+            auto m3 = Contains("different");
+            auto composed2 = composed1 || m3;
+            REQUIRE_THAT(testStringForMatching2(), !composed1);
+            REQUIRE_THAT(testStringForMatching2(), composed2);
+        }
+
 
     template<typename Range>
     struct EqualsRangeMatcher : Catch::MatcherGenericBase {