Fix section filtering to make sense

Specifically, this commit makes the `-c`/`--section` parameter
strictly ordered and hierarchical, unlike how it behaved before,
which was a huge mess -- see #3038 for details.

Closes #3038

docs/generators.md

@@ -252,9 +252,23 @@ struct IGenerator : GeneratorUntypedBase {
     // Returns user-friendly string showing the current generator element
     // Does not have to be overridden, IGenerator provides default implementation
     virtual std::string stringifyImpl() const;
+
+    /**
+     * Customization point for `skipToNthElement`
+     *
+     * Does not have to be overridden, there is a default implementation.
+     * Can be overridden for better performance.
+     *
+     * If there are not enough elements, shall throw an error.
+     *
+     * Going backwards is not supported.
+     */
+    virtual void skipToNthElementImpl( std::size_t n );
 };
 ```
 
+> `skipToNthElementImpl` was added in Catch2 vX.Y.Z
+
 However, to be able to use your custom generator inside `GENERATE`, it
 will need to be wrapped inside a `GeneratorWrapper<T>`.
 `GeneratorWrapper<T>` is a value wrapper around a

examples/300-Gen-OwnGenerator.cpp

@@ -39,6 +39,22 @@ public:
         current_number = m_dist(m_rand);
         return true;
     }
+
+    // Note: this improves the performance only a bit, but it is here
+    //       to show how you can override the skip functionality.
+    void skipToNthElementImpl( std::size_t n ) override {
+        auto current_index = currentElementIndex();
+        assert(current_index <= n);
+        // We cannot jump forward the underlying generator directly,
+        // because we do not know how many bits each distributed number
+        // would consume to be generated.
+        for (; current_index < n; ++current_index) {
+            (void)m_dist(m_rand);
+        }
+
+        // We do not have to touch the current element index; it is handled
+        // by the base class.
+    }
 };
 
 // Avoids -Wweak-vtables

src/catch2/interfaces/catch_interfaces_generatortracker.cpp

@@ -7,6 +7,8 @@
 // SPDX-License-Identifier: BSL-1.0
 
 #include <catch2/interfaces/catch_interfaces_generatortracker.hpp>
+#include <catch2/generators/catch_generators.hpp>
+
 #include <string>
 
 namespace Catch {
@@ -21,6 +23,30 @@ namespace Catch {
             return ret;
         }
 
+        void GeneratorUntypedBase::skipToNthElementImpl( std::size_t n ) {
+            for ( size_t i = m_currentElementIndex; i < n; ++i ) {
+                bool isValid = next();
+                if ( !isValid ) {
+                    Detail::throw_generator_exception(
+                        "Coud not jump to Nth element: not enough elements" );
+                }
+            }
+        }
+
+        void GeneratorUntypedBase::skipToNthElement( std::size_t n ) {
+            if ( n < m_currentElementIndex ) {
+                Detail::throw_generator_exception(
+                    "Tried to jump generator backwards" );
+            }
+            skipToNthElementImpl(n);
+
+            // Fixup tracking after moving the generator forward
+            //  * Ensure that the correct element index is set after skipping
+            //  * Invalidate cache
+            m_currentElementIndex = n;
+            m_stringReprCache.clear();
+        }
+
         StringRef GeneratorUntypedBase::currentElementAsString() const {
             if ( m_stringReprCache.empty() ) {
                 m_stringReprCache = stringifyImpl();

src/catch2/interfaces/catch_interfaces_generatortracker.hpp

@@ -35,6 +35,15 @@ namespace Catch {
             //! Customization point for `currentElementAsString`
             virtual std::string stringifyImpl() const = 0;
 
+            /**
+             * Customization point for skipping to the n-th element
+             *
+             * Defaults to successively calling `countedNext`. If there
+             * are not enough elements to reach the nth one, will throw
+             * an error.
+             */
+            virtual void skipToNthElementImpl( std::size_t n );
+
         public:
             GeneratorUntypedBase() = default;
             // Generation of copy ops is deprecated (and Clang will complain)
@@ -58,6 +67,13 @@ namespace Catch {
 
             std::size_t currentElementIndex() const { return m_currentElementIndex; }
 
+            /**
+             * Moves the generator forward **to** the n-th element
+             *
+             * Cannot move backwards.
+             */
+            void skipToNthElement( std::size_t n );
+
             /**
              * Returns generator's current element as user-friendly string.
              *

src/catch2/internal/catch_run_context.cpp

@@ -129,12 +129,8 @@ namespace Catch {
 
                         for ( auto const& child : m_children ) {
                             if ( child->isSectionTracker() &&
-                                 std::find( filters.begin(),
-                                            filters.end(),
-                                            static_cast<SectionTracker const&>(
-                                                *child )
-                                                .trimmedName() ) !=
-                                     filters.end() ) {
+                                 static_cast<SectionTracker const&>( *child )
+                                         .trimmedName() == filters[0] ) {
                                 return true;
                             }
                         }

src/catch2/internal/catch_test_case_tracker.cpp

@@ -172,9 +172,9 @@ namespace TestCaseTracking {
     bool SectionTracker::isComplete() const {
         bool complete = true;
 
-        if (m_filters.empty()
+        if ( m_filters.empty()
             || m_filters[0].empty()
-            || std::find(m_filters.begin(), m_filters.end(), m_trimmed_name) != m_filters.end()) {
+            || m_filters[0] == m_trimmed_name ) {
             complete = TrackerBase::isComplete();
         }
         return complete;

tests/CMakeLists.txt

@@ -310,38 +310,23 @@ set_tests_properties(UnmatchedOutputFilter
     PASS_REGULAR_EXPRESSION "No test cases matched '\\[this-tag-does-not-exist\\]'"
 )
 
-add_test(NAME FilteredSection-1 COMMAND $<TARGET_FILE:SelfTest> \#1394 -c RunSection)
-set_tests_properties(FilteredSection-1 PROPERTIES FAIL_REGULAR_EXPRESSION "No tests ran")
-add_test(NAME FilteredSection-2 COMMAND $<TARGET_FILE:SelfTest> \#1394\ nested -c NestedRunSection -c s1)
-set_tests_properties(FilteredSection-2 PROPERTIES FAIL_REGULAR_EXPRESSION "No tests ran")
+add_test(NAME FilteredSections::SimpleExample::1 COMMAND $<TARGET_FILE:SelfTest> \#1394 -c RunSection)
+set_tests_properties(FilteredSections::SimpleExample::1 PROPERTIES FAIL_REGULAR_EXPRESSION "No tests ran")
+add_test(NAME FilteredSections::SimpleExample::2 COMMAND $<TARGET_FILE:SelfTest> \#1394\ nested -c NestedRunSection -c s1)
+set_tests_properties(FilteredSections::SimpleExample::2 PROPERTIES FAIL_REGULAR_EXPRESSION "No tests ran")
 
 add_test(
   NAME
-    FilteredSection::GeneratorsDontCauseInfiniteLoop-1
+    FilteredSections::GeneratorsDontCauseInfiniteLoop
   COMMAND
     $<TARGET_FILE:SelfTest> "#2025: original repro" -c "fov_0"
 )
-set_tests_properties(FilteredSection::GeneratorsDontCauseInfiniteLoop-1
+set_tests_properties(FilteredSections::GeneratorsDontCauseInfiniteLoop
   PROPERTIES
     PASS_REGULAR_EXPRESSION "inside with fov: 0" # This should happen
     FAIL_REGULAR_EXPRESSION "inside with fov: 1" # This would mean there was no filtering
 )
 
-# GENERATE between filtered sections (both are selected)
-add_test(
-  NAME
-    FilteredSection::GeneratorsDontCauseInfiniteLoop-2
-  COMMAND
-    $<TARGET_FILE:SelfTest> "#2025: same-level sections"
-    -c "A"
-    -c "B"
-    --colour-mode none
-)
-set_tests_properties(FilteredSection::GeneratorsDontCauseInfiniteLoop-2
-  PROPERTIES
-    PASS_REGULAR_EXPRESSION "All tests passed \\(4 assertions in 1 test case\\)"
-)
-
 add_test(NAME ApprovalTests
   COMMAND
     Python3::Interpreter
@@ -694,6 +679,14 @@ set_tests_properties("Bazel::RngSeedEnvVar::MalformedValueIsIgnored"
     PASS_REGULAR_EXPRESSION "Randomness seeded to: 17171717"
 )
 
+add_test(NAME "FilteredSections::DifferentSimpleFilters"
+  COMMAND
+      Python3::Interpreter "${CMAKE_CURRENT_LIST_DIR}/TestScripts/testSectionFiltering.py" $<TARGET_FILE:SelfTest>
+)
+set_tests_properties("FilteredSections::DifferentSimpleFilters"
+  PROPERTIES
+    LABELS "uses-python"
+)
 
 list(APPEND CATCH_TEST_TARGETS SelfTest)
 set(CATCH_TEST_TARGETS ${CATCH_TEST_TARGETS} PARENT_SCOPE)

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

@@ -168,6 +168,7 @@ Nor would this
 :test-result: PASS GENERATE can combine literals and generators
 :test-result: PASS Generators -- adapters
 :test-result: PASS Generators -- simple
+:test-result: PASS Generators can be skipped forward
 :test-result: PASS Generators internals
 :test-result: PASS Greater-than inequalities with different epsilons
 :test-result: PASS Hashers with different seed produce different hash with same test case

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

@@ -166,6 +166,7 @@
 :test-result: PASS GENERATE can combine literals and generators
 :test-result: PASS Generators -- adapters
 :test-result: PASS Generators -- simple
+:test-result: PASS Generators can be skipped forward
 :test-result: PASS Generators internals
 :test-result: PASS Greater-than inequalities with different epsilons
 :test-result: PASS Hashers with different seed produce different hash with same test case

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

@@ -787,6 +787,13 @@ Generators.tests.cpp:<line number>: passed: j < i for: -1 < 3
 Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 12 > 1
 Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 12 > 2
 Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 12 > 3
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.currentElementIndex() == 0 for: 0 == 0
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.currentElementIndex() == 3 for: 3 == 3
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.get() == 3 for: 3 == 3
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.currentElementIndex() == 5 for: 5 == 5
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.get() == 5 for: 5 == 5
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.skipToNthElement( 3 )
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.skipToNthElement( 6 )
 GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 123 for: 123 == 123
 GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
 GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
@@ -2888,7 +2895,7 @@ InternalBenchmark.tests.cpp:<line number>: passed: med == 18. for: 18.0 == 18.0
 InternalBenchmark.tests.cpp:<line number>: passed: q3 == 23. for: 23.0 == 23.0
 Misc.tests.cpp:<line number>: passed:
 Misc.tests.cpp:<line number>: passed:
-test cases:  435 |  317 passed |  95 failed | 6 skipped | 17 failed as expected
-assertions: 2303 | 2105 passed | 157 failed | 41 failed as expected
+test cases:  436 |  318 passed |  95 failed | 6 skipped | 17 failed as expected
+assertions: 2310 | 2112 passed | 157 failed | 41 failed as expected
 
 

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

@@ -785,6 +785,13 @@ Generators.tests.cpp:<line number>: passed: j < i for: -1 < 3
 Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 12 > 1
 Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 12 > 2
 Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 12 > 3
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.currentElementIndex() == 0 for: 0 == 0
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.currentElementIndex() == 3 for: 3 == 3
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.get() == 3 for: 3 == 3
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.currentElementIndex() == 5 for: 5 == 5
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.get() == 5 for: 5 == 5
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.skipToNthElement( 3 )
+GeneratorsImpl.tests.cpp:<line number>: passed: generator.skipToNthElement( 6 )
 GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 123 for: 123 == 123
 GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
 GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
@@ -2877,7 +2884,7 @@ InternalBenchmark.tests.cpp:<line number>: passed: med == 18. for: 18.0 == 18.0
 InternalBenchmark.tests.cpp:<line number>: passed: q3 == 23. for: 23.0 == 23.0
 Misc.tests.cpp:<line number>: passed:
 Misc.tests.cpp:<line number>: passed:
-test cases:  435 |  317 passed |  95 failed | 6 skipped | 17 failed as expected
-assertions: 2303 | 2105 passed | 157 failed | 41 failed as expected
+test cases:  436 |  318 passed |  95 failed | 6 skipped | 17 failed as expected
+assertions: 2310 | 2112 passed | 157 failed | 41 failed as expected
 
 

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

@@ -1719,6 +1719,6 @@ due to unexpected exception with message:
   Why would you throw a std::string?
 
 ===============================================================================
-test cases:  435 |  335 passed |  76 failed | 7 skipped | 17 failed as expected
-assertions: 2282 | 2105 passed | 136 failed | 41 failed as expected
+test cases:  436 |  336 passed |  76 failed | 7 skipped | 17 failed as expected
+assertions: 2289 | 2112 passed | 136 failed | 41 failed as expected
 

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

@@ -5831,6 +5831,43 @@ Generators.tests.cpp:<line number>: PASSED:
 with expansion:
   12 > 3
 
+-------------------------------------------------------------------------------
+Generators can be skipped forward
+-------------------------------------------------------------------------------
+GeneratorsImpl.tests.cpp:<line number>
+...............................................................................
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( generator.currentElementIndex() == 0 )
+with expansion:
+  0 == 0
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( generator.currentElementIndex() == 3 )
+with expansion:
+  3 == 3
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( generator.get() == 3 )
+with expansion:
+  3 == 3
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( generator.currentElementIndex() == 5 )
+with expansion:
+  5 == 5
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( generator.get() == 5 )
+with expansion:
+  5 == 5
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_THROWS( generator.skipToNthElement( 3 ) )
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_THROWS( generator.skipToNthElement( 6 ) )
+
 -------------------------------------------------------------------------------
 Generators internals
   Single value
@@ -19295,6 +19332,6 @@ Misc.tests.cpp:<line number>
 Misc.tests.cpp:<line number>: PASSED:
 
 ===============================================================================
-test cases:  435 |  317 passed |  95 failed | 6 skipped | 17 failed as expected
-assertions: 2303 | 2105 passed | 157 failed | 41 failed as expected
+test cases:  436 |  318 passed |  95 failed | 6 skipped | 17 failed as expected
+assertions: 2310 | 2112 passed | 157 failed | 41 failed as expected
 

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

@@ -5829,6 +5829,43 @@ Generators.tests.cpp:<line number>: PASSED:
 with expansion:
   12 > 3
 
+-------------------------------------------------------------------------------
+Generators can be skipped forward
+-------------------------------------------------------------------------------
+GeneratorsImpl.tests.cpp:<line number>
+...............................................................................
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( generator.currentElementIndex() == 0 )
+with expansion:
+  0 == 0
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( generator.currentElementIndex() == 3 )
+with expansion:
+  3 == 3
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( generator.get() == 3 )
+with expansion:
+  3 == 3
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( generator.currentElementIndex() == 5 )
+with expansion:
+  5 == 5
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( generator.get() == 5 )
+with expansion:
+  5 == 5
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_THROWS( generator.skipToNthElement( 3 ) )
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_THROWS( generator.skipToNthElement( 6 ) )
+
 -------------------------------------------------------------------------------
 Generators internals
   Single value
@@ -19284,6 +19321,6 @@ Misc.tests.cpp:<line number>
 Misc.tests.cpp:<line number>: PASSED:
 
 ===============================================================================
-test cases:  435 |  317 passed |  95 failed | 6 skipped | 17 failed as expected
-assertions: 2303 | 2105 passed | 157 failed | 41 failed as expected
+test cases:  436 |  318 passed |  95 failed | 6 skipped | 17 failed as expected
+assertions: 2310 | 2112 passed | 157 failed | 41 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="140" skipped="12" tests="2315" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
+  <testsuite name="<exe-name>" errors="17" failures="140" skipped="12" tests="2322" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
     <properties>
       <property name="random-seed" value="1"/>
       <property name="filters" value="&quot;*&quot; ~[!nonportable] ~[!benchmark] ~[approvals]"/>
@@ -837,6 +837,7 @@ at Message.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="Generators -- simple" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators -- simple/one" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators -- simple/two" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Generators can be skipped forward" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals/Single value" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals/Preset values" time="{duration}" status="run"/>

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

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <testsuites>
-  <testsuite name="<exe-name>" errors="17" failures="140" skipped="12" tests="2315" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
+  <testsuite name="<exe-name>" errors="17" failures="140" skipped="12" tests="2322" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
     <properties>
       <property name="random-seed" value="1"/>
       <property name="filters" value="&quot;*&quot; ~[!nonportable] ~[!benchmark] ~[approvals]"/>
@@ -836,6 +836,7 @@ at Message.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="Generators -- simple" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators -- simple/one" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators -- simple/two" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="Generators can be skipped forward" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals/Single value" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="Generators internals/Preset values" time="{duration}" status="run"/>

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

@@ -144,6 +144,7 @@ at AssertionHandler.tests.cpp:<line number>
   </file>
   <file path="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp">
     <testCase name="Filter generator throws exception for empty generator" duration="{duration}"/>
+    <testCase name="Generators can be skipped forward" duration="{duration}"/>
     <testCase name="Generators internals" duration="{duration}"/>
     <testCase name="Generators internals/Single value" duration="{duration}"/>
     <testCase name="Generators internals/Preset values" duration="{duration}"/>

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

@@ -143,6 +143,7 @@ at AssertionHandler.tests.cpp:<line number>
   </file>
   <file path="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp">
     <testCase name="Filter generator throws exception for empty generator" duration="{duration}"/>
+    <testCase name="Generators can be skipped forward" duration="{duration}"/>
     <testCase name="Generators internals" duration="{duration}"/>
     <testCase name="Generators internals/Single value" duration="{duration}"/>
     <testCase name="Generators internals/Preset values" duration="{duration}"/>

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

@@ -1430,6 +1430,20 @@ ok {test-number} - 4u * i > str.size() for: 12 > 1
 ok {test-number} - 4u * i > str.size() for: 12 > 2
 # Generators -- simple
 ok {test-number} - 4u * i > str.size() for: 12 > 3
+# Generators can be skipped forward
+ok {test-number} - generator.currentElementIndex() == 0 for: 0 == 0
+# Generators can be skipped forward
+ok {test-number} - generator.currentElementIndex() == 3 for: 3 == 3
+# Generators can be skipped forward
+ok {test-number} - generator.get() == 3 for: 3 == 3
+# Generators can be skipped forward
+ok {test-number} - generator.currentElementIndex() == 5 for: 5 == 5
+# Generators can be skipped forward
+ok {test-number} - generator.get() == 5 for: 5 == 5
+# Generators can be skipped forward
+ok {test-number} - generator.skipToNthElement( 3 )
+# Generators can be skipped forward
+ok {test-number} - generator.skipToNthElement( 6 )
 # Generators internals
 ok {test-number} - gen.get() == 123 for: 123 == 123
 # Generators internals
@@ -4627,5 +4641,5 @@ ok {test-number} - q3 == 23. for: 23.0 == 23.0
 ok {test-number} -
 # xmlentitycheck
 ok {test-number} -
-1..2315
+1..2322
 

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

@@ -1428,6 +1428,20 @@ ok {test-number} - 4u * i > str.size() for: 12 > 1
 ok {test-number} - 4u * i > str.size() for: 12 > 2
 # Generators -- simple
 ok {test-number} - 4u * i > str.size() for: 12 > 3
+# Generators can be skipped forward
+ok {test-number} - generator.currentElementIndex() == 0 for: 0 == 0
+# Generators can be skipped forward
+ok {test-number} - generator.currentElementIndex() == 3 for: 3 == 3
+# Generators can be skipped forward
+ok {test-number} - generator.get() == 3 for: 3 == 3
+# Generators can be skipped forward
+ok {test-number} - generator.currentElementIndex() == 5 for: 5 == 5
+# Generators can be skipped forward
+ok {test-number} - generator.get() == 5 for: 5 == 5
+# Generators can be skipped forward
+ok {test-number} - generator.skipToNthElement( 3 )
+# Generators can be skipped forward
+ok {test-number} - generator.skipToNthElement( 6 )
 # Generators internals
 ok {test-number} - gen.get() == 123 for: 123 == 123
 # Generators internals
@@ -4616,5 +4630,5 @@ ok {test-number} - q3 == 23. for: 23.0 == 23.0
 ok {test-number} -
 # xmlentitycheck
 ok {test-number} -
-1..2315
+1..2322
 

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

@@ -414,6 +414,8 @@
 ##teamcity[testFinished name='Generators -- adapters' duration="{duration}"]
 ##teamcity[testStarted name='Generators -- simple']
 ##teamcity[testFinished name='Generators -- simple' duration="{duration}"]
+##teamcity[testStarted name='Generators can be skipped forward']
+##teamcity[testFinished name='Generators can be skipped forward' duration="{duration}"]
 ##teamcity[testStarted name='Generators internals']
 ##teamcity[testFinished name='Generators internals' duration="{duration}"]
 ##teamcity[testStarted name='Greater-than inequalities with different epsilons']

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

@@ -414,6 +414,8 @@
 ##teamcity[testFinished name='Generators -- adapters' duration="{duration}"]
 ##teamcity[testStarted name='Generators -- simple']
 ##teamcity[testFinished name='Generators -- simple' duration="{duration}"]
+##teamcity[testStarted name='Generators can be skipped forward']
+##teamcity[testFinished name='Generators can be skipped forward' duration="{duration}"]
 ##teamcity[testStarted name='Generators internals']
 ##teamcity[testFinished name='Generators internals' duration="{duration}"]
 ##teamcity[testStarted name='Greater-than inequalities with different epsilons']

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

@@ -6605,6 +6605,65 @@ Approx( 1.30000000000000004 )
     </Section>
     <OverallResult success="true" skips="0"/>
   </TestCase>
+  <TestCase name="Generators can be skipped forward" tags="[generators]" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+    <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.currentElementIndex() == 0
+      </Original>
+      <Expanded>
+        0 == 0
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.currentElementIndex() == 3
+      </Original>
+      <Expanded>
+        3 == 3
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.get() == 3
+      </Original>
+      <Expanded>
+        3 == 3
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.currentElementIndex() == 5
+      </Original>
+      <Expanded>
+        5 == 5
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.get() == 5
+      </Original>
+      <Expanded>
+        5 == 5
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE_THROWS" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.skipToNthElement( 3 )
+      </Original>
+      <Expanded>
+        generator.skipToNthElement( 3 )
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE_THROWS" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.skipToNthElement( 6 )
+      </Original>
+      <Expanded>
+        generator.skipToNthElement( 6 )
+      </Expanded>
+    </Expression>
+    <OverallResult success="true" skips="0"/>
+  </TestCase>
   <TestCase name="Generators internals" tags="[generators][internals]" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
     <Section name="Single value" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
       <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
@@ -22324,6 +22383,6 @@ Approx( -1.95996398454005449 )
     </Section>
     <OverallResult success="true" skips="0"/>
   </TestCase>
-  <OverallResults successes="2105" failures="157" expectedFailures="41" skips="12"/>
-  <OverallResultsCases successes="317" failures="95" expectedFailures="17" skips="6"/>
+  <OverallResults successes="2112" failures="157" expectedFailures="41" skips="12"/>
+  <OverallResultsCases successes="318" failures="95" expectedFailures="17" skips="6"/>
 </Catch2TestRun>

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

@@ -6605,6 +6605,65 @@ Approx( 1.30000000000000004 )
     </Section>
     <OverallResult success="true" skips="0"/>
   </TestCase>
+  <TestCase name="Generators can be skipped forward" tags="[generators]" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+    <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.currentElementIndex() == 0
+      </Original>
+      <Expanded>
+        0 == 0
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.currentElementIndex() == 3
+      </Original>
+      <Expanded>
+        3 == 3
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.get() == 3
+      </Original>
+      <Expanded>
+        3 == 3
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.currentElementIndex() == 5
+      </Original>
+      <Expanded>
+        5 == 5
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.get() == 5
+      </Original>
+      <Expanded>
+        5 == 5
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE_THROWS" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.skipToNthElement( 3 )
+      </Original>
+      <Expanded>
+        generator.skipToNthElement( 3 )
+      </Expanded>
+    </Expression>
+    <Expression success="true" type="REQUIRE_THROWS" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Original>
+        generator.skipToNthElement( 6 )
+      </Original>
+      <Expanded>
+        generator.skipToNthElement( 6 )
+      </Expanded>
+    </Expression>
+    <OverallResult success="true" skips="0"/>
+  </TestCase>
   <TestCase name="Generators internals" tags="[generators][internals]" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
     <Section name="Single value" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
       <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
@@ -22323,6 +22382,6 @@ Approx( -1.95996398454005449 )
     </Section>
     <OverallResult success="true" skips="0"/>
   </TestCase>
-  <OverallResults successes="2105" failures="157" expectedFailures="41" skips="12"/>
-  <OverallResultsCases successes="317" failures="95" expectedFailures="17" skips="6"/>
+  <OverallResults successes="2112" failures="157" expectedFailures="41" skips="12"/>
+  <OverallResultsCases successes="318" failures="95" expectedFailures="17" skips="6"/>
 </Catch2TestRun>

tests/SelfTest/IntrospectiveTests/Details.tests.cpp

@@ -7,6 +7,7 @@
 // SPDX-License-Identifier: BSL-1.0
 
 #include <catch2/catch_test_macros.hpp>
+#include <catch2/generators/catch_generators.hpp>
 #include <catch2/internal/catch_enforce.hpp>
 #include <catch2/internal/catch_case_insensitive_comparisons.hpp>
 #include <catch2/internal/catch_optional.hpp>
@@ -170,3 +171,64 @@ TEST_CASE( "Decomposer checks that the argument is 0 when handling "
 
     CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
 }
+
+
+TEST_CASE( "foo", "[approvals]" ) {
+    SECTION( "A" ) {
+        SECTION( "B1" ) { REQUIRE( true ); }
+        SECTION( "B2" ) { REQUIRE( true ); }
+        SECTION( "B3" ) { REQUIRE( true ); }
+    }
+}
+
+TEST_CASE( "bar", "[approvals]" ) {
+    REQUIRE( true );
+    SECTION( "A" ) {
+        SECTION( "B1" ) { REQUIRE( true ); }
+        SECTION( "B2" ) { REQUIRE( true ); }
+        SECTION( "B3" ) { REQUIRE( true ); }
+    }
+    REQUIRE( true );
+}
+
+TEST_CASE( "baz", "[approvals]" ) {
+    SECTION( "A" ) { REQUIRE( true ); }
+    auto _ = GENERATE( 1, 2, 3 );
+    (void)_;
+    SECTION( "B" ) { REQUIRE( true ); }
+}
+
+TEST_CASE( "qux", "[approvals]" ) {
+    REQUIRE( true );
+    SECTION( "A" ) { REQUIRE( true ); }
+    auto _ = GENERATE( 1, 2, 3 );
+    (void)_;
+    SECTION( "B" ) { REQUIRE( true ); }
+    REQUIRE( true );
+}
+
+TEST_CASE( "corge", "[approvals]" ) {
+    REQUIRE( true );
+    SECTION( "A" ) {
+        REQUIRE( true );
+    }
+    auto i = GENERATE( 1, 2, 3 );
+    DYNAMIC_SECTION( "i=" << i ) {
+        REQUIRE( true );
+    }
+    REQUIRE( true );
+}
+
+TEST_CASE("grault", "[approvals]") {
+    REQUIRE( true );
+    SECTION( "A" ) {
+        REQUIRE( true );
+    }
+    SECTION("B") {
+        auto i = GENERATE( 1, 2, 3 );
+        DYNAMIC_SECTION( "i=" << i ) {
+            REQUIRE( true );
+        }
+    }
+    REQUIRE( true );
+}

tests/SelfTest/IntrospectiveTests/GeneratorsImpl.tests.cpp

@@ -85,7 +85,7 @@ TEST_CASE("Generators internals", "[generators][internals]") {
                 filter([](int) { return false; }, values({ 1, 2, 3 })),
                 Catch::GeneratorException);
         }
-        
+
         // Non-trivial usage
         SECTION("Out-of-line predicates are copied into the generator") {
             auto evilNumber = Catch::Detail::make_unique<int>(2);
@@ -586,3 +586,21 @@ TEST_CASE("from_range(container) supports ADL begin/end and arrays", "[generator
     }
 
 }
+
+TEST_CASE( "Generators can be skipped forward", "[generators]" ) {
+    auto generator = Catch::Generators::FixedValuesGenerator<int>( { 0, 1, 2, 3, 4, 5 } );
+    REQUIRE( generator.currentElementIndex() == 0 );
+
+    generator.skipToNthElement( 3 );
+    REQUIRE( generator.currentElementIndex() == 3 );
+    REQUIRE( generator.get() == 3 );
+
+    generator.skipToNthElement( 5 );
+    REQUIRE( generator.currentElementIndex() == 5 );
+    REQUIRE( generator.get() == 5 );
+
+    // Backwards
+    REQUIRE_THROWS( generator.skipToNthElement( 3 ) );
+    // Past the end
+    REQUIRE_THROWS( generator.skipToNthElement( 6 ) );
+}

tests/SelfTest/UsageTests/Tricky.tests.cpp

@@ -354,27 +354,9 @@ TEST_CASE("#1514: stderr/stdout is not captured in tests aborted by an exception
     FAIL("1514");
 }
 
-
-TEST_CASE( "#2025: -c shouldn't cause infinite loop", "[sections][generators][regression][.approvals]" ) {
-    SECTION( "Check cursor from buffer offset" ) {
-        auto bufPos = GENERATE_REF( range( 0, 44 ) );
-        WHEN( "Buffer position is " << bufPos ) { REQUIRE( 1 == 1 ); }
-    }
-}
-
 TEST_CASE("#2025: original repro", "[sections][generators][regression][.approvals]") {
     auto fov = GENERATE(true, false);
     DYNAMIC_SECTION("fov_" << fov) {
         std::cout << "inside with fov: " << fov << '\n';
     }
 }
-
-TEST_CASE("#2025: same-level sections", "[sections][generators][regression][.approvals]") {
-    SECTION("A") {
-        SUCCEED();
-    }
-    auto i = GENERATE(1, 2, 3);
-    SECTION("B") {
-        REQUIRE(i < 4);
-    }
-}

tests/TestScripts/testSectionFiltering.py

@@ -0,0 +1,128 @@
+#!/usr/bin/env python3
+
+#              Copyright Catch2 Authors
+# Distributed under the Boost Software License, Version 1.0.
+#   (See accompanying file LICENSE.txt or copy at
+#        https://www.boost.org/LICENSE_1_0.txt)
+
+# SPDX-License-Identifier: BSL-1.0
+
+"""
+This test script verifies the behaviour of the legacy section filtering
+using `-c`, `--section` CLI parameters.
+
+This is done by having a hardcoded set of test filter + section filter
+combinations, together with the expected number of assertions that will
+be run inside the test for given filter combo.
+"""
+
+import os
+import subprocess
+import sys
+from typing import Tuple, List
+import xml.etree.ElementTree as ET
+
+def make_cli_filter(section_names: Tuple[str, ...]) -> List[str]:
+    final = []
+    for name in section_names:
+        final.append('--section')
+        final.append(name)
+    return final
+
+def run_one_test(binary_path: str, test_name: str, section_names: Tuple[str, ...], expected_assertions: int):
+    cmd = [
+      binary_path,
+      '--reporter', 'xml',
+      test_name
+    ]
+    cmd.extend(make_cli_filter(section_names))
+    try:
+        ret = subprocess.run(
+            cmd,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            check=True,
+            universal_newlines=True,
+        )
+        stdout = ret.stdout
+    except subprocess.SubprocessError as ex:
+        print('Could not run "{}"'.format(cmd))
+        print("Return code: {}".format(ex.returncode))
+        print("stdout: {}".format(ex.stdout))
+        print("stderr: {}".format(ex.stderr))
+        raise
+
+    try:
+        tree = ET.fromstring(stdout)
+    except ET.ParseError as ex:
+        print("Invalid XML: '{}'".format(ex))
+        raise
+
+    # Validate that we ran exactly 1 test case, and it passed
+    test_case_stats = tree.find('OverallResultsCases')
+    expected_testcases = {'successes' : '1', 'failures' : '0', 'expectedFailures': '0', 'skips': '0'}
+    assert test_case_stats.attrib == expected_testcases, f'We did not run single passing test case as expected. {test_name}: {test_case_stats.attrib}'
+
+    # Validate that we got exactly the expected number of passing assertions
+    expected_assertions = {'successes' : str(expected_assertions), 'failures' : '0', 'expectedFailures': '0', 'skips': '0'}
+    assertion_stats = tree.find('OverallResults')
+    assert assertion_stats.attrib == expected_assertions, f'"{test_name}": {assertion_stats.attrib} vs {expected_assertions}'
+
+
+# Inputs taken from issue #3038
+tests = {
+  'foo': (
+    ((), 3),
+    (('A',), 3),
+    (('A', 'B'), 0),
+    (('A', 'B1'), 1),
+    (('A', 'B2'), 1),
+    (('A', 'B1', 'B2'), 1),
+    (('A', 'B2', 'XXXX'), 1),
+  ),
+  'bar': (
+    ((), 9),
+    (('A',), 9),
+    (('A', 'B1'), 3),
+    (('XXXX',), 2),
+    (('B1',), 2),
+    (('A', 'B1', 'B2'), 3),
+  ),
+  'baz': (
+    ((), 4),
+    (('A',), 1),
+    (('A', 'B'), 1),
+    (('A', 'XXXX'), 1),
+    (('B',), 3),
+    (('XXXX',), 0),
+  ),
+  'qux': (
+    ((), 12),
+    (('A',), 7),
+    (('B',), 9),
+    (('B', 'XXXX'), 9),
+    (('XXXX',), 6),
+  ),
+  'corge': (
+    ((), 12),
+    (('i=2',), 7),
+    (('i=3',), 7),
+  ),
+  'grault': (
+    ((), 12),
+    (('A',), 3),
+    (('B',), 9),
+    (('B', 'i=1'), 7),
+    (('B', 'XXXX'), 6),
+  ),
+}
+
+if len(sys.argv) != 2:
+    print("Wrong number of arguments, expected just the path to Catch2 SelfTest binary")
+    exit(1)
+
+bin_path = os.path.abspath(sys.argv[1])
+
+for test_filter, specs in tests.items():
+    for section_path, expected_assertions in specs:
+        run_one_test(bin_path, test_filter, section_path, expected_assertions)