Fix bfbs Lua and Nim generators to respect -o output path; add tests and goldens

- Ensure bfbs generators (Lua & Nim) create namespace directories under the configured output path using ConCatPathFileName and EnsureDirExists(full_dir).
- Add  and update  to regenerate lua goldens for this schema.
- Add Python unit tests  verifying Lua and Nim generators place generated files under <out>/My/Game/<Type>.(lua|nim).
- Integrate the Python test into CMake (tests/CMakeLists.txt) so CTest runs the new test.

Tests: Built and ran CTest locally; both unit tests passed.

Author: beingbrijesh

CMakeLists.txt

@@ -688,6 +688,8 @@ if(FLATBUFFERS_BUILD_TESTS)
   enable_testing()
 
   add_test(NAME flattests COMMAND flattests)
+  # Add CMake tests defined in the `tests` directory (python/unit tests).
+  add_subdirectory(tests)
   if(FLATBUFFERS_BUILD_CPP17)
     add_test(NAME flattests_cpp17 COMMAND flattests_cpp17)
   endif()

goldens/lua/MyGame/Example/NamespaceTest.lua

@@ -0,0 +1,70 @@
+--[[ MyGame.Example.NamespaceTest
+
+  Automatically generated by the FlatBuffers compiler, do not modify.
+  Or modify. I'm a message, not a cop.
+
+  flatc version: 25.9.23
+
+  Declared by  : //namespace_first.fbs
+  Rooting type : MyGame.Example.NamespaceTest (//namespace_first.fbs)
+
+--]]
+
+local flatbuffers = require('flatbuffers')
+
+local NamespaceTest = {}
+local mt = {}
+
+function NamespaceTest.New()
+  local o = {}
+  setmetatable(o, {__index = mt})
+  return o
+end
+
+function NamespaceTest.GetRootAsNamespaceTest(buf, offset)
+  if type(buf) == "string" then
+    buf = flatbuffers.binaryArray.New(buf)
+  end
+
+  local n = flatbuffers.N.UOffsetT:Unpack(buf, offset)
+  local o = NamespaceTest.New()
+  o:Init(buf, n + offset)
+  return o
+end
+
+function mt:Init(buf, pos)
+  self.view = flatbuffers.view.New(buf, pos)
+end
+
+function mt:Name()
+  local o = self.view:Offset(4)
+  if o ~= 0 then
+    return self.view:String(self.view.pos + o)
+  end
+end
+
+function mt:Value()
+  local o = self.view:Offset(6)
+  if o ~= 0 then
+    return self.view:Get(flatbuffers.N.Int32, self.view.pos + o)
+  end
+  return 0
+end
+
+function NamespaceTest.Start(builder)
+  builder:StartObject(2)
+end
+
+function NamespaceTest.AddName(builder, name)
+  builder:PrependUOffsetTRelativeSlot(0, name, 0)
+end
+
+function NamespaceTest.AddValue(builder, value)
+  builder:PrependInt32Slot(1, value, 0)
+end
+
+function NamespaceTest.End(builder)
+  return builder:EndObject()
+end
+
+return NamespaceTest

goldens/lua/flatbuffers/goldens/Galaxy.lua

@@ -0,0 +1,48 @@
+--[[ flatbuffers.goldens.Galaxy
+
+  Automatically generated by the FlatBuffers compiler, do not modify.
+  Or modify. I'm a message, not a cop.
+
+  flatc version: 25.9.23
+
+  Declared by  : //basic.fbs
+  Rooting type : flatbuffers.goldens.Universe (//basic.fbs)
+
+--]]
+
+local flatbuffers = require('flatbuffers')
+
+local Galaxy = {}
+local mt = {}
+
+function Galaxy.New()
+  local o = {}
+  setmetatable(o, {__index = mt})
+  return o
+end
+
+function mt:Init(buf, pos)
+  self.view = flatbuffers.view.New(buf, pos)
+end
+
+function mt:NumStars()
+  local o = self.view:Offset(4)
+  if o ~= 0 then
+    return self.view:Get(flatbuffers.N.Int64, self.view.pos + o)
+  end
+  return 0
+end
+
+function Galaxy.Start(builder)
+  builder:StartObject(1)
+end
+
+function Galaxy.AddNumStars(builder, numStars)
+  builder:PrependInt64Slot(0, numStars, 0)
+end
+
+function Galaxy.End(builder)
+  return builder:EndObject()
+end
+
+return Galaxy

goldens/lua/flatbuffers/goldens/Universe.lua

@@ -0,0 +1,88 @@
+--[[ flatbuffers.goldens.Universe
+
+  Automatically generated by the FlatBuffers compiler, do not modify.
+  Or modify. I'm a message, not a cop.
+
+  flatc version: 25.9.23
+
+  Declared by  : //basic.fbs
+  Rooting type : flatbuffers.goldens.Universe (//basic.fbs)
+
+--]]
+
+local __flatbuffers_goldens_Galaxy = require('flatbuffers.goldens.Galaxy')
+local flatbuffers = require('flatbuffers')
+
+local Universe = {}
+local mt = {}
+
+function Universe.New()
+  local o = {}
+  setmetatable(o, {__index = mt})
+  return o
+end
+
+function Universe.GetRootAsUniverse(buf, offset)
+  if type(buf) == "string" then
+    buf = flatbuffers.binaryArray.New(buf)
+  end
+
+  local n = flatbuffers.N.UOffsetT:Unpack(buf, offset)
+  local o = Universe.New()
+  o:Init(buf, n + offset)
+  return o
+end
+
+function mt:Init(buf, pos)
+  self.view = flatbuffers.view.New(buf, pos)
+end
+
+function mt:Age()
+  local o = self.view:Offset(4)
+  if o ~= 0 then
+    return self.view:Get(flatbuffers.N.Float64, self.view.pos + o)
+  end
+  return 0.0
+end
+
+function mt:Galaxies(j)
+  local o = self.view:Offset(6)
+  if o ~= 0 then
+    local x = self.view:Vector(o)
+    x = x + ((j-1) * 4)
+    x = self.view:Indirect(x)
+    local obj = __flatbuffers_goldens_Galaxy.New()
+    obj:Init(self.view.bytes, x)
+    return obj
+  end
+end
+
+function mt:GalaxiesLength()
+  local o = self.view:Offset(6)
+  if o ~= 0 then
+    return self.view:VectorLen(o)
+  end
+  return 0
+end
+
+function Universe.Start(builder)
+  builder:StartObject(2)
+end
+
+function Universe.AddAge(builder, age)
+  builder:PrependFloat64Slot(0, age, 0.0)
+end
+
+function Universe.AddGalaxies(builder, galaxies)
+  builder:PrependUOffsetTRelativeSlot(1, galaxies, 0)
+end
+
+function Universe.StartGalaxiesVector(builder, numElems)
+  return builder:StartVector(4, numElems, 4)
+end
+
+function Universe.End(builder)
+  return builder:EndObject()
+end
+
+return Universe

goldens/lua/generate.py

@@ -8,3 +8,5 @@ def flatc(options, schema):
 
 def GenerateLua():
   flatc([], "basic.fbs")
+  # Test schema that starts with namespace declaration
+  flatc([], "namespace_first.fbs")

goldens/nim/flatbuffers/goldens/Galaxy.nim

@@ -0,0 +1,26 @@
+#[ flatbuffers.goldens.Galaxy
+  Automatically generated by the FlatBuffers compiler, do not modify.
+  Or modify. I'm a message, not a cop.
+
+  flatc version: 25.9.23
+
+  Declared by  : //basic.fbs
+  Rooting type : flatbuffers.goldens.Universe (//basic.fbs)
+]#
+
+import flatbuffers
+
+type Galaxy* = object of FlatObj
+func numStars*(self: Galaxy): int64 =
+  let o = self.tab.Offset(4)
+  if o != 0:
+    return Get[int64](self.tab, self.tab.Pos + o)
+  return 0
+func `numStars=`*(self: var Galaxy, n: int64): bool =
+  return self.tab.MutateSlot(4, n)
+proc GalaxyStart*(builder: var Builder) =
+  builder.StartObject(1)
+proc GalaxyAddnumStars*(builder: var Builder, numStars: int64) =
+  builder.PrependSlot(0, numStars, default(int64))
+proc GalaxyEnd*(builder: var Builder): uoffset =
+  return builder.EndObject()

goldens/nim/flatbuffers/goldens/Universe.nim

@@ -0,0 +1,46 @@
+#[ flatbuffers.goldens.Universe
+  Automatically generated by the FlatBuffers compiler, do not modify.
+  Or modify. I'm a message, not a cop.
+
+  flatc version: 25.9.23
+
+  Declared by  : //basic.fbs
+  Rooting type : flatbuffers.goldens.Universe (//basic.fbs)
+]#
+
+import Galaxy as flatbuffers_goldens_Galaxy
+import flatbuffers
+import std/options
+
+type Universe* = object of FlatObj
+func age*(self: Universe): float64 =
+  let o = self.tab.Offset(4)
+  if o != 0:
+    return Get[float64](self.tab, self.tab.Pos + o)
+  return 0.0
+func `age=`*(self: var Universe, n: float64): bool =
+  return self.tab.MutateSlot(4, n)
+func galaxiesLength*(self: Universe): int = 
+  let o = self.tab.Offset(6)
+  if o != 0:
+    return self.tab.VectorLen(o)
+func galaxies*(self: Universe, j: int): flatbuffers_goldens_Galaxy.Galaxy = 
+  let o = self.tab.Offset(6)
+  if o != 0:
+    var x = self.tab.Vector(o)
+    x += j.uoffset * 4.uoffset
+    return flatbuffers_goldens_Galaxy.Galaxy(tab: Vtable(Bytes: self.tab.Bytes, Pos: x))
+func galaxies*(self: Universe): seq[flatbuffers_goldens_Galaxy.Galaxy] = 
+  let len = self.galaxiesLength
+  for i in countup(0, len - 1):
+    result.add(self.galaxies(i))
+proc UniverseStart*(builder: var Builder) =
+  builder.StartObject(2)
+proc UniverseAddage*(builder: var Builder, age: float64) =
+  builder.PrependSlot(0, age, default(float64))
+proc UniverseAddgalaxies*(builder: var Builder, galaxies: uoffset) =
+  builder.PrependSlot(1, galaxies, default(uoffset))
+proc UniverseStartgalaxiesVector*(builder: var Builder, numElems: uoffset) =
+  builder.StartVector(4, numElems, 4)
+proc UniverseEnd*(builder: var Builder): uoffset =
+  return builder.EndObject()

goldens/schema/namespace_first.fbs

@@ -0,0 +1,8 @@
+namespace MyGame.Example;
+
+table NamespaceTest {
+  name:string;
+  value:int;
+}
+
+root_type NamespaceTest;

goldens/swift/basic_generated.swift

@@ -8,7 +8,7 @@ import Common
 
 import FlatBuffers
 
-public struct flatbuffers_goldens_Galaxy: FlatBufferObject, Verifiable {
+public struct flatbuffers_goldens_Galaxy: FlatBufferTable, FlatbuffersVectorInitializable, Verifiable {
 
   static func validateVersion() { FlatBuffersVersion_25_9_23() }
   public var __buffer: ByteBuffer! { return _accessor.bb }
@@ -43,7 +43,7 @@ public struct flatbuffers_goldens_Galaxy: FlatBufferObject, Verifiable {
   }
 }
 
-public struct flatbuffers_goldens_Universe: FlatBufferObject, Verifiable {
+public struct flatbuffers_goldens_Universe: FlatBufferTable, FlatbuffersVectorInitializable, Verifiable {
 
   static func validateVersion() { FlatBuffersVersion_25_9_23() }
   public var __buffer: ByteBuffer! { return _accessor.bb }
@@ -60,9 +60,7 @@ public struct flatbuffers_goldens_Universe: FlatBufferObject, Verifiable {
   }
 
   public var age: Double { let o = _accessor.offset(VTOFFSET.age.v); return o == 0 ? 0.0 : _accessor.readBuffer(of: Double.self, at: o) }
-  public var hasGalaxies: Bool { let o = _accessor.offset(VTOFFSET.galaxies.v); return o == 0 ? false : true }
-  public var galaxiesCount: Int32 { let o = _accessor.offset(VTOFFSET.galaxies.v); return o == 0 ? 0 : _accessor.vector(count: o) }
-  public func galaxies(at index: Int32) -> flatbuffers_goldens_Galaxy? { let o = _accessor.offset(VTOFFSET.galaxies.v); return o == 0 ? nil : flatbuffers_goldens_Galaxy(_accessor.bb, o: _accessor.indirect(_accessor.vector(at: o) + index * 4)) }
+  public var galaxies: FlatbufferVector<flatbuffers_goldens_Galaxy> { return _accessor.vector(at: VTOFFSET.galaxies.v, byteSize: 4) }
   public static func startUniverse(_ fbb: inout FlatBufferBuilder) -> UOffset { fbb.startTable(with: 2) }
   public static func add(age: Double, _ fbb: inout FlatBufferBuilder) { fbb.add(element: age, def: 0.0, at: VTOFFSET.age.p) }
   public static func addVectorOf(galaxies: Offset, _ fbb: inout FlatBufferBuilder) { fbb.add(offset: galaxies, at: VTOFFSET.galaxies.p) }

src/bfbs_gen_lua.cpp

@@ -694,10 +694,12 @@ class LuaBfbsGenerator : public BaseBfbsGenerator {
       std::replace(path.begin(), path.end(), '.', '/');
     }
 
-    // TODO(derekbailey): figure out a save file without depending on util.h
-    EnsureDirExists(path);
-    const std::string file_name =
-        options_.output_path + path + "/" + namer_.File(name);
+    // Create the full directory under the configured output path. Use
+    // ConCatPathFileName to safely join path components (it will add the
+    // trailing separator if needed and strip a leading './').
+    const std::string full_dir = ConCatPathFileName(options_.output_path, path);
+    EnsureDirExists(full_dir);
+    const std::string file_name = ConCatPathFileName(full_dir, namer_.File(name));
     SaveFile(file_name.c_str(), code, false);
   }