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")
```
* 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
* feat: Added support for fixed sized arrays to python
Problem:
We encountered that using fixed arrays from C++ to python that python would
not read those arrays correctly due to no size information being encoded in the byte
array itself.
Fix:
Encode the sizes within the generated python file during code generation.
Specfically we add GetArrayAsNumpy to the python version of table, which takes as input
the length of the vector. When generating the python message files we include this length
from the VectorType().fixed_length.
* fix: added digit support for camel case to snake case conversion
Problem:
When including a number in the message name we would encounter cases where SnakeCase would
not add the appropirate breaks. e.g. Int32Stamped -> int_32stamped rather than int_32_stamped.
Fix:
To fix this we can add the condition that we check if the current character is not lower and
not a digit, that we check if the previous character was a lower or digit. If it was a lower
or digit then we add the break.
* fix: Array support for structures
Problem:
The python generated code for handling non-struct and struct vectors
and arrays was inconsistent. The calls to populate the obj api was
creating incorrect code.
Solution:
To fix this the VectorOfStruct and VectorOfNonStruct was rewritten
to handle array cases and bring the two methods in line which each
other.
Testing:
PythonTesting.sh now correctly runs and generates the code for
array_test.fbs.
Minor modifications were done on the test to use the new index
accessor for struct arrays and the script correctly sources the
location of the python code.
* chore: clang format changes
* Added code generated by scripts/generate_code. Modified GetArrayOfNonStruct slightly
to allow for function overloading allowing the user to get a single element of an array
or the whole array.
* Added new_line parameter to OffsetPrefix to allow optional new lines to be added.
This allows us to use the GenIndents method that automatically adds new lines instead.
* Reupload of generated code from the scripts/generate_code.py
* Removed new line in GetVectorAsNumpy.
* Updated Array lengths to use Length methods where possible. Added fallthrough for GenTypePointer. Added digit check to CamelToSnake method. Added and modified tests for ToSnakeCase and CamelToSnake.
* Added range check on the getter methods for vector and array types. Renamed == as is for python
