Print the active section/generator selection

When a section/generator selection (`-c`, `-g`, or `-p`) is in effect,
the console and compact reporters now print the active path filters next
to the existing `Filters:` line, e.g.

    Filters: "foo"
    Path filters: c:"A" g:0

Section filters are serialized as `c:"<filter>"` and generator filters as
`g:<filter>`, mirroring the `-p`/`--path-filter` syntax. This makes it
obvious what has actually been selected, which is especially helpful when
a filter combination ends up running no assertions.

Closes #3099

Author: ShivaPriyanShanmuga

docs/filtering-execution-path.md

@@ -19,6 +19,20 @@ behaviour, which does not affect generators at all. If you also use either
 `-g`/`--generator-index`, or `-p`/`--path-filter`, you will get the new
 behaviour, which can also filter generator elements.
 
+When path filters are in effect, the console and compact reporters print
+the active selection at the start of the run, next to the `Filters:` line,
+e.g.
+
+```
+Filters: "foo"
+Path filters: c:"A" g:0
+```
+
+Section filters are shown as `c:"<filter>"` and generator filters as
+`g:<filter>`, mirroring the `-p`/`--path-filter` syntax. This makes it
+easy to see exactly what has been selected when a filter combination ends
+up running no assertions.
+
 Both the new and old filter behaviours include some potentially surprising
 things:
   * Code outside of sections being skipped will still be executed. E.g.

src/catch2/reporters/catch_reporter_compact.cpp

@@ -215,6 +215,12 @@ class AssertionPrinter {
                          << m_config->testSpec()
                          << '\n';
             }
+            if ( !m_config->getPathFilters().empty() ) {
+                m_stream << m_colour->guardColour( Colour::BrightYellow )
+                         << "Path filters: "
+                         << serializePathFilters( m_config->getPathFilters() )
+                         << '\n';
+            }
             m_stream << "RNG seed: " << getSeed() << '\n'
                      << std::flush;
         }

src/catch2/reporters/catch_reporter_console.cpp

@@ -530,6 +530,11 @@ void ConsoleReporter::testRunStarting(TestRunInfo const& _testRunInfo) {
         m_stream << m_colour->guardColour( Colour::BrightYellow ) << "Filters: "
                  << m_config->testSpec() << '\n';
     }
+    if ( !m_config->getPathFilters().empty() ) {
+        m_stream << m_colour->guardColour( Colour::BrightYellow )
+                 << "Path filters: "
+                 << serializePathFilters( m_config->getPathFilters() ) << '\n';
+    }
     m_stream << "Randomness seeded to: " << getSeed() << '\n'
              << std::flush;
 }

src/catch2/reporters/catch_reporter_helpers.cpp

@@ -9,6 +9,7 @@
 #include <catch2/reporters/catch_reporter_helpers.hpp>
 #include <catch2/interfaces/catch_interfaces_config.hpp>
 #include <catch2/internal/catch_console_width.hpp>
+#include <catch2/internal/catch_path_filter.hpp>
 #include <catch2/internal/catch_errno_guard.hpp>
 #include <catch2/internal/catch_textflow.hpp>
 #include <catch2/internal/catch_reusable_string_stream.hpp>
@@ -101,6 +102,26 @@ namespace Catch {
         return serialized;
     }
 
+    std::string serializePathFilters( std::vector<PathFilter> const& filters ) {
+        ReusableStringStream rss;
+        bool first = true;
+        for ( auto const& filter : filters ) {
+            if ( !first ) {
+                rss << ' ';
+            }
+            first = false;
+            switch ( filter.type ) {
+            case PathFilter::For::Section:
+                rss << "c:\"" << filter.filter << '"';
+                break;
+            case PathFilter::For::Generator:
+                rss << "g:" << filter.filter;
+                break;
+            }
+        }
+        return rss.str();
+    }
+
     std::ostream& operator<<( std::ostream& out, lineOfChars value ) {
         for ( size_t idx = 0; idx < CATCH_CONFIG_CONSOLE_WIDTH - 1; ++idx ) {
             out.put( value.c );

src/catch2/reporters/catch_reporter_helpers.hpp

@@ -21,6 +21,7 @@ namespace Catch {
     class IConfig;
     class TestCaseHandle;
     class ColourImpl;
+    struct PathFilter;
 
     // Returns double formatted as %.3f (format expected on output)
     std::string getFormattedDuration( double duration );
@@ -30,6 +31,16 @@ namespace Catch {
 
     std::string serializeFilters( std::vector<std::string> const& filters );
 
+    /**
+     * Serializes the active section/generator path filters into a string
+     * that resembles the `-p`/`--path-filter` command line syntax.
+     *
+     * Section filters are serialized as `c:"<filter>"`, generator filters
+     * as `g:<filter>`. The filters are separated by a single space and kept
+     * in the order in which they were specified.
+     */
+    std::string serializePathFilters( std::vector<PathFilter> const& filters );
+
     struct lineOfChars {
         char c;
         constexpr lineOfChars( char c_ ): c( c_ ) {}

tests/CMakeLists.txt

@@ -666,6 +666,33 @@ foreach(reporterName # "Automake" - the simple .trs format does not support any
   )
 endforeach()
 
+# The console and compact reporters print the active section/generator
+# selection (path filters), so that it is obvious what has been selected.
+foreach(reporterName "compact"
+                     "console")
+  add_test(NAME "Reporters:PathFilters:Section:${reporterName}"
+    COMMAND
+      $<TARGET_FILE:SelfTest> "Tracker"
+        --reporter ${reporterName}
+        --section "section name"
+  )
+  set_tests_properties("Reporters:PathFilters:Section:${reporterName}"
+    PROPERTIES
+      PASS_REGULAR_EXPRESSION "Path filters: c:\"section name\""
+  )
+
+  add_test(NAME "Reporters:PathFilters:Generator:${reporterName}"
+    COMMAND
+      $<TARGET_FILE:SelfTest> "Generators internals"
+        --reporter ${reporterName}
+        --generator-index 0
+  )
+  set_tests_properties("Reporters:PathFilters:Generator:${reporterName}"
+    PROPERTIES
+      PASS_REGULAR_EXPRESSION "Path filters: g:0"
+  )
+endforeach()
+
 add_test(NAME "Bazel::RngSeedEnvVar::JustEnv"
   COMMAND
     $<TARGET_FILE:SelfTest> "Factorials are computed"