Fix absolute/relative path handling in --affected

The conditional was incorrectly reversed due to my misreading of
`std::error_code` so we never attempted to look up the absolute or
relative path for paths passed in to `--affected`.

It was a bit tricky to do unit test for absolute paths as they need to
be generated beforehand.  This commit is less lazy and includes unit
tests for absolute and relative path handling by generating files in the
CMake generation step.

CMakeLists.txt

@@ -49,6 +49,17 @@ set(CPACK_NSIS_MODIFY_PATH ON)
 set(CPACK_NSIS_IGNORE_LICENSE_PAGE ON)
 include(CPack)
 
+# Generate test files for the absolute/relative unit test
+get_filename_component(ABSOLUTE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/tests/absolute/relative" ABSOLUTE)
+string(REPLACE ":" "$:" ABSOLUTE_PATH_ESCAPED "${ABSOLUTE_PATH}")
+file(WRITE "${CMAKE_CURRENT_SOURCE_DIR}/tests/absolute/changed.txt" "${ABSOLUTE_PATH}\nabsolute")
+string(APPEND NINJA_CONTENTS "rule copy\n")
+string(APPEND NINJA_CONTENTS "  command = ninja --version \$in -> \$out\n")
+string(APPEND NINJA_CONTENTS "build out_relative: copy absolute\n")
+string(APPEND NINJA_CONTENTS "build out_absolute: copy ${ABSOLUTE_PATH_ESCAPED}\n")
+file(WRITE "${CMAKE_CURRENT_SOURCE_DIR}/tests/absolute/build.ninja" "${NINJA_CONTENTS}")
+file(COPY_FILE "${CMAKE_CURRENT_SOURCE_DIR}/tests/absolute/build.ninja" "${CMAKE_CURRENT_SOURCE_DIR}/tests/absolute/expected.ninja")
+
 file(
     GLOB TRIMJA_TESTS
     LIST_DIRECTORIES true

src/trimutil.cpp

@@ -668,10 +668,10 @@ void TrimUtil::trim(std::ostream& output,
     // If that does not indicate a path, try the absolute path
     std::filesystem::path p(line);
     if (!p.is_absolute()) {
-      std::error_code okay;
+      std::error_code error;
       const std::filesystem::path& absolute =
-          attempted.emplace_back(std::filesystem::absolute(p, okay));
-      if (okay) {
+          attempted.emplace_back(std::filesystem::absolute(p, error));
+      if (!error) {
         std::string absoluteStr = absolute.string();
         const std::optional<std::size_t> index = graph.findPath(absoluteStr);
         if (index.has_value()) {
@@ -689,10 +689,10 @@ void TrimUtil::trim(std::ostream& output,
     // If neither indicates a path, then try the path relative to the ninja
     // file
     if (!p.is_relative()) {
-      std::error_code okay;
+      std::error_code error;
       const std::filesystem::path& relative =
-          attempted.emplace_back(std::filesystem::relative(p, okay));
-      if (okay) {
+          attempted.emplace_back(std::filesystem::relative(p, error));
+      if (!error) {
         std::string relativeStr = relative.string();
         const std::optional<std::size_t> index = graph.findPath(relativeStr);
         if (index.has_value()) {

tests/absolute/.gitignore

@@ -0,0 +1,4 @@
+# These files are generated at configure time
+changed.txt
+build.ninja
+expected.ninja

tests/absolute/bootstrap.ninja

@@ -0,0 +1 @@
+include build.ninja