Reworked keep prefix (#7456)

* reworked keep prefix

* checking in missing schema

* fix flatc path for build scripts

.github/workflows/build.yml

@@ -80,6 +80,8 @@ jobs:
       run: msbuild.exe FlatBuffers.sln /p:Configuration=Release /p:Platform=x64
     - name: test
       run: Release\flattests.exe
+    - name: flatc tests
+      run: python3 tests/flatc/main.py --flatc Release\flatc.exe
     - name: upload build artifacts
       uses: actions/upload-artifact@v1
       with:
@@ -181,6 +183,8 @@ jobs:
       run: |
         chmod +x _build/Release/flatc
         ./_build/Release/flatc --version
+    - name: flatc tests
+      run: python3 tests/flatc/main.py --flatc ./_build/Release/flatc
     - name: upload build artifacts
       uses: actions/upload-artifact@v1
       with:

src/idl_gen_cpp.cpp

@@ -239,22 +239,34 @@ class CppGenerator : public BaseGenerator {
     // interdependence between them.
     std::stable_sort(included_files.begin(), included_files.end());
 
-    // Get any prefix of the file being parsed, so that included filed can be
-    // properly stripped.
-    auto prefix = flatbuffers::StripFileName(parser_.file_being_parsed_) +
-                  flatbuffers::kPathSeparator;
+    // The absolute path of the file being parsed.
+    const std::string parsed_path =
+        flatbuffers::StripFileName(AbsolutePath(parser_.file_being_parsed_));
 
     for (const std::string &included_file : included_files) {
-      auto file_without_extension = flatbuffers::StripExtension(included_file);
-      code_ +=
-          "#include \"" +
-          GeneratedFileName(
-              opts_.include_prefix,
-              opts_.keep_prefix
-                  ? flatbuffers::StripPrefix(file_without_extension, prefix)
-                  : flatbuffers::StripPath(file_without_extension),
-              opts_) +
-          "\"";
+      // The base name of the file, without path or extensions.
+      std::string basename =
+          flatbuffers::StripPath(flatbuffers::StripExtension(included_file));
+
+      // If we are keeping the prefix
+      if (opts_.keep_prefix) {
+        // The absolute path of the included file.
+        const std::string included_path =
+            flatbuffers::StripFileName(AbsolutePath(included_file));
+
+        // The relative path of the parsed file to the included file.
+        const std::string relative_path =
+            RelativeToRootPath(parsed_path, included_path).substr(2);
+
+        // Only consider cases where the included path is a subdirectory of the
+        // parsed path.
+        if (strncmp("..", relative_path.c_str(), 2) != 0) {
+          basename = relative_path + kPathSeparator + basename;
+        }
+      }
+
+      code_ += "#include \"" +
+               GeneratedFileName(opts_.include_prefix, basename, opts_) + "\"";
     }
 
     if (!parser_.native_included_files_.empty() || !included_files.empty()) {

tests/flatc/bar/bar_with_foo.fbs

@@ -0,0 +1,6 @@
+include "foo.fbs";
+include "baz/baz.fbs";
+
+table BarWithFoo {
+  foo:Foo;
+}