This commit significantly improves the developer experience for the Python Object-Based API by overhauling the generated `__init__` method for `T`-suffixed classes.
Previously, `T` objects had to be instantiated with an empty constructor, and their fields had to be populated manually one by one. This was verbose and not idiomatic Python.
This change modifies the Python code generator (`GenInitialize`) to produce `__init__` methods that are:
1. **Keyword-Argument-Friendly**: The constructor now accepts all table/struct fields as keyword arguments, allowing for concise, single-line object creation.
2. **Fully Typed**: The signature of the `__init__` method is now annotated with Python type hints. This provides immediate benefits for static analysis tools (like Mypy) and IDEs, enabling better autocompletion and type checking.
3. **Correctly Optional**: The generator now correctly wraps types in `Optional[...]` if their default value is `None`. This applies to strings, vectors, and other nullable fields, ensuring strict type safety.
The new approach remains **fully backward-compatible**, as all arguments have default values. Existing code that uses the empty constructor will continue to work without modification.
#### Example of a Generated `__init__`
**Before:**
```python
class KeyValueT(object):
def __init__(self):
self.key = None # type: str
self.value = None # type: str
```
**After:**
```python
class KeyValueT(object):
def __init__(self, key: Optional[str] = None, value: Optional[str] = None):
self.key = key
self.value = value
```
#### Example of User Code
**Before:**
```python
# Old, verbose way
kv = KeyValueT()
kv.key = "instrument"
kv.value = "EUR/USD"
```
**After:**
```python
# New, Pythonic way
kv = KeyValueT(key="instrument", value="EUR/USD")
```
Using the : syntax leads to non member attributes.
> If an attribute is defined in the class body with a type annotation
> but with no assigned value, a type checker should assume this is a non-member attribute
```
class Pet(Enum):
genus: str # Non-member attribute
species: str # Non-member attribute
CAT = 1 # Member attribute
DOG = 2 # Member attribute
```
https://typing.python.org/en/latest/spec/enums.html#defining-members
This prevents the include of the type defined in the pyi,
otherwise this leads to error message like this:
error: Name XYZ already defined (possibly by an import) [no-redef]
* [Python] Use correct type for str with None
Otherwise mypy will correctly flag code like this
def __init__(self):
self.fooBar = None # type: Optional[str]
error: Incompatible types in assignment (expression has type "None", variable has type "str")
* [Python] Make list type optional as they can contain None
This allows enums to be type check with mypy.
They will still behave like ints ->
> IntEnum is the same as Enum,
> but its members are also integers and can be used anywhere
> that an integer can be used.
> If any integer operation is performed with an IntEnum member,
> the resulting value loses its enumeration status.
https://docs.python.org/3/library/enum.html#enum.IntEnum
Only if the --python-typing flag is set.
* [Python] Generate `.pyi` stub files when `--python-typing` is on.
To support this change, the following modifications were made:
- added a new option to disable `numpy` helpers generation;
- added a new flag to control the target Python version:
`--python-version` can be one of the following:
- `0.x.x` – compatible with any Python version;
- `2.x.x` – compatible with Python 2;
- `3.x.x` – compatible with Python 3.
- added codegen utilities for Python;
- added a note that the generated .py file is empty.
* [Python] Update Bazel build rules.
* [Python] Update Bazel build rules.
* [Python] Run buildifier on BUILD.bazel files.
---------
Co-authored-by: Derek Bailey <derekbailey@google.com>
* First working hack of adding 64-bit. Don't judge :)
* Made vector_downward work on 64 bit types
* vector_downward uses size_t, added offset64 to reflection
* cleaned up adding offset64 in parser
* Add C++ testing skeleton for 64-bit
* working test for CreateVector64
* working >2 GiB buffers
* support for large strings
* simplified CreateString<> to just provide the offset type
* generalize CreateVector template
* update test_64.afb due to upstream format change
* Added Vector64 type, which is just an alias for vector ATM
* Switch to Offset64 for Vector64
* Update for reflection bfbs output change
* Starting to add support for vector64 type in C++
* made a generic CreateVector that can handle different offsets and vector types
* Support for 32-vector with 64-addressing
* Vector64 basic builder + tests working
* basic support for json vector64 support
* renamed fields in test_64bit.fbs to better reflect their use
* working C++ vector64 builder
* Apply --annotate-sparse-vector to 64-bit tests
* Enable Vector64 for --annotate-sparse-vectors
* Merged from upstream
* Add `near_string` field for testing 32-bit offsets alongside
* keep track of where the 32-bit and 64-bit regions are for flatbufferbuilder
* move template<> outside class body for GCC
* update run.sh to build and run tests
* basic assertion for adding 64-bit offset at the wrong time
* started to separate `FlatBufferBuilder` into two classes, 1 64-bit aware, the other not
* add test for nested flatbuffer vector64, fix bug in alignment of big vectors
* fixed CreateDirect method by iterating by Offset64 first
* internal refactoring of flatbufferbuilder
* block not supported languages in the parser from using 64-bit
* evolution tests for adding a vector64 field
* conformity tests for adding/removing offset64 attributes
* ensure test is for a big buffer
* add parser error tests for `offset64` and `vector64` attributes
* add missing static that GCC only complains about
* remove stdint-uintn.h header that gets automatically added
* move 64-bit CalculateOffset internal
* fixed return size of EndVector
* various fixes on windows
* add SizeT to vector_downward
* minimze range of size changes in vector and builder
* reworked how tracking if 64-offsets are added
* Add ReturnT to EndVector
* small cleanups
* remove need for second Array definition
* combine IndirectHelpers into one definition
* started support for vector of struct
* Support for 32/64-vectors of structs + Offset64
* small cleanups
* add verification for vector64
* add sized prefix for 64-bit buffers
* add fuzzer for 64-bit
* add example of adding many vectors using a wrapper table
* run the new -bfbs-gen-embed logic on the 64-bit tests
* remove run.sh and fix cmakelist issue
* fixed bazel rules
* fixed some PR comments
* add 64-bit tests to cmakelist
* optionally generate type prefixes and suffixes for python code
* fix codegen error when qualified name is empty
* WIP: Python typing
* more progress towards python typing
* Further iterate on Python generated code typing
* clang-format
* Regenerate code
* add documentation for Python type annotations option
* generate code with Python type annotations
* handle forward references
* clang-format
* Fix C/C++ Create<Type>Direct with sorted vectors
If a struct has a key the vector has to be sorted. To sort the vector
you can't use "const".
* Changes due to code review
* Improve code readability
* Add generate of JSON schema to string to lib
* option indent_step is supported
* Remove unused variables
* Fix break in test
* Fix style to be consistent with rest of the code
* [TS] Fix reserved words as arguments (#6955)
* [TS] Fix generation of reserved words in object api (#7106)
* [TS] Fix generation of object api
* [TS] Fix MakeCamel -> ConvertCase
* [C#] Fix collision of field name and type name
* [TS] Add test for struct of struct of struct
* Update generated files
* Add missing files
* [TS] Fix query of null/undefined fields in object api
* Add .Net verfier
* Add some fuzz tests for .Net
* Remove additional files
* Fix .net test
* Changes due to PR
* Fix generated files
---------
Co-authored-by: Derek Bailey <derekbailey@google.com>
ToCamelCase(input, true) converts first char to upper case, but
ToCamelCase(input, false) keeps the case of the first char. We are
changing its behavior to force a lower case.
Co-authored-by: Derek Bailey <derekbailey@google.com>
* [Kotlin] Control the generation of reflection with --reflect-names.
Tested:
```
$ cmake -G "Unix Makefiles" && make && ./tests/flatc/main.py
...
KotlinTests.EnumValAttributes
[PASSED]
KotlinTests.EnumValAttributes_ReflectNames
[PASSED]
KotlinTests: 2 of 2 passsed
...
35 of 35 tests passed
```
* [Kotlin] Fix SampleBinary by converting Byte to UByte for ubyte fields.
* [Kotlin] Annotate all generated classes with kotlin.ExperimentalUnsignedTypes.
* [Kotlin] Only generate nullable return types if the field is not required
* [Kotlin] Fix generated code formatting according to kotlin style guide
Co-authored-by: Derek Bailey <derekbailey@google.com>
Co-authored-by: Paulo Pinheiro <paulovictor.pinheiro@gmail.com>
* Add support for key lookup for tables in Go
* Run clang format
* Run go fmt on tests
* Remove TODO in tests
* Update LookupByKey API
* Update LookupByKey API
* Don't use resolvePointer in expectEq
* Use generated getters instead of reading values directly from buffer
* Fix typo
Co-authored-by: Derek Bailey <derekbailey@google.com>
+/-inf were not being handled, and so invalid typescript was being
generated when a float/double had an infinite default value. NaN was
being handled correctly.
Co-authored-by: Derek Bailey <derekbailey@google.com>
Co-authored-by: Casper <casperneo@uchicago.edu>
* feat: Fixed the issue with nested unions relying on InitFromBuf.
Problem: Issue #7569
Nested Unions were broken with the introduction of parsing buffers with an initial encoding offset.
Fix:
Revert the InitFromBuf method to the previous version and introduction of InitFromPackedBuf that allows
users to read types from packed buffers applying the offset automatically.
Test:
Added in TestNestedUnionTables to test the encoding and decoding ability using a nested table with a
union field.
* fix: Uncommented generate code command
