Support filtering on both sections and generators (#3069)

Not being able to filter generators to specific element has been regularly
causing problems. It was possible to use a dynamic section to run tests
for specific element in a generator, at least if the element had a nice
string representation, but the test case would still run once per element
in the generator.

With this change, it is possible to have the generator return only one
specific element, and do so based on the index, rather than the string
representation of the element. This enables simple debugging of tests
that fail for specific generator element.

1 files changed, 44 insertions, 1 deletions

diff --git a/src/catch2/internal/catch_commandline.cpp b/src/catch2/internal/catch_commandline.cpp
index 34bda5e2..4ce42397 100644
--- a/src/catch2/internal/catch_commandline.cpp
+++ b/src/catch2/internal/catch_commandline.cpp
@@ -216,6 +216,43 @@ namespace Catch {
             return ParserResult::ok( ParseResultType::Matched );
         };
 
+        auto const setSectionFilter = [&]( std::string const& sectionFilter ) {
+            config.pathFilters.emplace_back( PathFilter::For::Section, trim(sectionFilter) );
+            return ParserResult::ok( ParseResultType::Matched );
+        };
+        auto const setGeneratorFilter = [&]( std::string const& generatorFilter ) {
+            if (generatorFilter != "*") {
+                // TODO: avoid re-parsing the index?
+                auto parsedIndex = parseUInt( generatorFilter );
+                if ( !parsedIndex ) {
+                    return ParserResult::runtimeError( "Could not parse '" +
+                                                       generatorFilter +
+                                                       "' as generator index" );
+                }
+            }
+            config.useNewPathFilteringBehaviour = true;
+            config.pathFilters.emplace_back( PathFilter::For::Generator, trim(generatorFilter) );
+            return ParserResult::ok( ParseResultType::Matched );
+        };
+        // Copy-capturing other `setFoo` functions enables calling them later,
+        // as the config ref remains valid, but the local lambda vars won't.
+        auto const setPathFilter = [=, &config]( std::string const& pathFilter ) {
+            config.useNewPathFilteringBehaviour = true;
+            if ( pathFilter.size() < 3 ) {
+                return ParserResult::runtimeError(
+                    "Path filter '" + pathFilter + "' is too short" );
+            }
+            if ( startsWith( pathFilter, "g:" ) ) {
+                return setGeneratorFilter( pathFilter.substr( 2 ) );
+            }
+            if ( startsWith( pathFilter, "c:" ) ) {
+                return setSectionFilter( pathFilter.substr( 2 ) );
+            }
+            return ParserResult::runtimeError( "Path filter '" + pathFilter +
+                                               "' has unknown type prefix" );
+        };
+
+
         auto cli
             = ExeName( config.processName )
             | Help( config.showHelp )
@@ -261,9 +298,15 @@ namespace Catch {
             | Opt( config.filenamesAsTags )
                 ["-#"]["--filenames-as-tags"]
                 ( "adds a tag for the filename" )
-            | Opt( config.sectionsToRun, "section name" )
+            | Opt( accept_many, setSectionFilter, "section name" )
                 ["-c"]["--section"]
                 ( "specify section to run" )
+            | Opt( accept_many, setGeneratorFilter, "index spec" )
+                ["-g"]["--generator-index"]
+                ( "specify generator elements to try" )
+            | Opt( accept_many, setPathFilter, "path filter spec" )
+                ["-p"]["--path-filter"]
+                ( "qualified path filter" )
             | Opt( setVerbosity, "quiet|normal|high" )
                 ["-v"]["--verbosity"]
                 ( "set output verbosity" )