22734550158

Committed 05 Mar 2026 08:06PM UTC coverage: 89.491%. Remained the same

Build # 22734550158

Build Type

push

github

Committed by

Giorgi

Commit Message

Add NULL handling support for scalar functions

Replace `isPureFunction` bool with `ScalarFunctionOptions`
record that supports `IsPureFunction` and `HandlesNulls`.

- Add `ScalarFunctionOptions` with `IsPureFunction` and
  `HandlesNulls` properties
- Bind `duckdb_scalar_function_set_special_handling` native
  method to enable NULL passthrough
- Update simplified scalar function extensions to validate
  nullable parameter types when `HandlesNulls` is true
- Propagate NULL correctly: nullable types get default,
  non-nullable types throw with a clear error message
- Update existing tests to use new options API

Coverage Stats

1287 of 1499 branches covered (85.86%)

Branch coverage included in aggregate %.

41 of 49 new or added lines in 3 files covered. (83.67%)

2 existing lines in 2 files now uncovered.

2630 of 2878 relevant lines covered (91.38%)

446353.59 hits per line

Source File
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88.37

/DuckDB.NET.Data/DuckDBConnection.ScalarFunction.cs

﻿using DuckDB.NET.Data.Connection;
using DuckDB.NET.Data.DataChunk.Reader;
using DuckDB.NET.Data.DataChunk.Writer;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

namespace DuckDB.NET.Data;

partial class DuckDBConnection
{
    public void RegisterScalarFunction<TResult>(string name, Action<IDuckDBDataWriter, ulong> action, ScalarFunctionOptions? options = null)
    {
        RegisterScalarMethod(name, (_, w, index) => action(w, index), TypeExtensions.GetLogicalType<TResult>(), varargs: false, options);
    }

    public void RegisterScalarFunction<T, TResult>(string name, Action<IReadOnlyList<IDuckDBDataReader>, IDuckDBDataWriter, ulong> action, ScalarFunctionOptions? options = null, bool @params = false)
    {
        RegisterScalarMethod(name, action, TypeExtensions.GetLogicalType<TResult>(), @params, options, TypeExtensions.GetLogicalType<T>());
    }

    public void RegisterScalarFunction<T1, T2, TResult>(string name, Action<IReadOnlyList<IDuckDBDataReader>, IDuckDBDataWriter, ulong> action, ScalarFunctionOptions? options = null)
    {
        RegisterScalarMethod(name, action, TypeExtensions.GetLogicalType<TResult>(), varargs: false, options,
            TypeExtensions.GetLogicalType<T1>(), TypeExtensions.GetLogicalType<T2>());
    }

    public void RegisterScalarFunction<T1, T2, T3, TResult>(string name, Action<IReadOnlyList<IDuckDBDataReader>, IDuckDBDataWriter, ulong> action, ScalarFunctionOptions? options = null)
    {
        RegisterScalarMethod(name, action, TypeExtensions.GetLogicalType<TResult>(), varargs: false, options,
            TypeExtensions.GetLogicalType<T1>(), TypeExtensions.GetLogicalType<T2>(), TypeExtensions.GetLogicalType<T3>());
    }

    public void RegisterScalarFunction<T1, T2, T3, T4, TResult>(string name, Action<IReadOnlyList<IDuckDBDataReader>, IDuckDBDataWriter, ulong> action, ScalarFunctionOptions? options = null)
    {
        RegisterScalarMethod(name, action, TypeExtensions.GetLogicalType<TResult>(), varargs: false, options,
            TypeExtensions.GetLogicalType<T1>(), TypeExtensions.GetLogicalType<T2>(),
            TypeExtensions.GetLogicalType<T3>(), TypeExtensions.GetLogicalType<T4>());
    }

    private unsafe void RegisterScalarMethod(string name, Action<IReadOnlyList<IDuckDBDataReader>, IDuckDBDataWriter, ulong> action, DuckDBLogicalType returnType,
                                             bool varargs, ScalarFunctionOptions? options, params DuckDBLogicalType[] parameterTypes)
    {
        var function = NativeMethods.ScalarFunction.DuckDBCreateScalarFunction();
        NativeMethods.ScalarFunction.DuckDBScalarFunctionSetName(function, name);

        if (varargs)
        {
            if (parameterTypes.Length != 1)
            {
                throw new InvalidOperationException("Cannot use params with multiple parameters");
            }

            NativeMethods.ScalarFunction.DuckDBScalarFunctionSetVarargs(function, parameterTypes[0]);
            parameterTypes[0].Dispose();
        }
        else
        {
            foreach (var type in parameterTypes)
            {
                NativeMethods.ScalarFunction.DuckDBScalarFunctionAddParameter(function, type);
                type.Dispose();
            }
        }

        // Functions with parameters default to pure; parameterless functions (e.g. random()) default to volatile
        var defaultPure = parameterTypes.Length > 0;
        if (!(options?.IsPureFunction ?? defaultPure))
        {
            NativeMethods.ScalarFunction.DuckDBScalarFunctionSetVolatile(function);
        }

        if (options?.HandlesNulls == true)
        {
            NativeMethods.ScalarFunction.DuckDBScalarFunctionSetSpecialHandling(function);
        }

        NativeMethods.ScalarFunction.DuckDBScalarFunctionSetReturnType(function, returnType);
        NativeMethods.ScalarFunction.DuckDBScalarFunctionSetFunction(function, &ScalarFunctionCallback);

        var info = new ScalarFunctionInfo(returnType, action);

        NativeMethods.ScalarFunction.DuckDBScalarFunctionSetExtraInfo(function, info.ToHandle(), &DestroyExtraInfo);

        var state = NativeMethods.ScalarFunction.DuckDBRegisterScalarFunction(NativeConnection, function);

        NativeMethods.ScalarFunction.DuckDBDestroyScalarFunction(ref function);

        if (!state.IsSuccess())
        {
            throw new InvalidOperationException($"Error registering user defined scalar function: {name}");
        }
    }

    [UnmanagedCallersOnly(CallConvs = [typeof(CallConvCdecl)])]
    private static void ScalarFunctionCallback(IntPtr info, IntPtr chunk, IntPtr outputVector)
    {
        VectorDataReaderBase[] readers = [];
        VectorDataWriterBase? writer = null;

        try
        {
            var dataChunk = new DuckDBDataChunk(chunk);

            var chunkSize = NativeMethods.DataChunks.DuckDBDataChunkGetSize(dataChunk);
            var handle = GCHandle.FromIntPtr(NativeMethods.ScalarFunction.DuckDBScalarFunctionGetExtraInfo(info));

            if (handle.Target is not ScalarFunctionInfo functionInfo)
            {
                throw new InvalidOperationException("User defined scalar function execution failed. Function extra info is null");
            }

            readers = new VectorDataReaderBase[NativeMethods.DataChunks.DuckDBDataChunkGetColumnCount(dataChunk)];

            for (var index = 0; index < readers.Length; index++)
            {
                var vector = NativeMethods.DataChunks.DuckDBDataChunkGetVector(dataChunk, index);
                using var logicalType = NativeMethods.Vectors.DuckDBVectorGetColumnType(vector);
                readers[index] = VectorDataReaderFactory.CreateReader(vector, logicalType);
            }

            writer = VectorDataWriterFactory.CreateWriter(outputVector, functionInfo.ReturnType);

            functionInfo.Action(readers, writer, chunkSize);
        }
        catch (Exception ex)
        {
            NativeMethods.ScalarFunction.DuckDBScalarFunctionSetError(info, ex.Message);
        }
        finally
        {
            foreach (var reader in readers)
            {
                reader.Dispose();
            }

            writer?.Dispose();
        }
    }

    [UnmanagedCallersOnly(CallConvs = [typeof(CallConvCdecl)])]
    private static void DestroyExtraInfo(IntPtr pointer) => pointer.FreeHandle();
}

1	using DuckDB.NET.Data.Connection;
2	using DuckDB.NET.Data.DataChunk.Reader;
3	using DuckDB.NET.Data.DataChunk.Writer;
4	using System.Runtime.CompilerServices;
5	using System.Runtime.InteropServices;
6
7	namespace DuckDB.NET.Data;
8
9	partial class DuckDBConnection
10	{
11	public void RegisterScalarFunction<TResult>(string name, Action<IDuckDBDataWriter, ulong> action, ScalarFunctionOptions? options = null)
12	{
13	RegisterScalarMethod(name, (_, w, index) => action(w, index), TypeExtensions.GetLogicalType<TResult>(), varargs: false, options);	12✔
14	}	6✔
15
16	public void RegisterScalarFunction<T, TResult>(string name, Action<IReadOnlyList<IDuckDBDataReader>, IDuckDBDataWriter, ulong> action, ScalarFunctionOptions? options = null, bool @params = false)
17	{
18	RegisterScalarMethod(name, action, TypeExtensions.GetLogicalType<TResult>(), @params, options, TypeExtensions.GetLogicalType<T>());	57✔
19	}	57✔
20
21	public void RegisterScalarFunction<T1, T2, TResult>(string name, Action<IReadOnlyList<IDuckDBDataReader>, IDuckDBDataWriter, ulong> action, ScalarFunctionOptions? options = null)
22	{
23	RegisterScalarMethod(name, action, TypeExtensions.GetLogicalType<TResult>(), varargs: false, options,	21✔
24	TypeExtensions.GetLogicalType<T1>(), TypeExtensions.GetLogicalType<T2>());	21✔
25	}	21✔
26
27	public void RegisterScalarFunction<T1, T2, T3, TResult>(string name, Action<IReadOnlyList<IDuckDBDataReader>, IDuckDBDataWriter, ulong> action, ScalarFunctionOptions? options = null)
28	{
29	RegisterScalarMethod(name, action, TypeExtensions.GetLogicalType<TResult>(), varargs: false, options,	6✔
30	TypeExtensions.GetLogicalType<T1>(), TypeExtensions.GetLogicalType<T2>(), TypeExtensions.GetLogicalType<T3>());	6✔
31	}	6✔
32
33	public void RegisterScalarFunction<T1, T2, T3, T4, TResult>(string name, Action<IReadOnlyList<IDuckDBDataReader>, IDuckDBDataWriter, ulong> action, ScalarFunctionOptions? options = null)
34	{
NEW 35	RegisterScalarMethod(name, action, TypeExtensions.GetLogicalType<TResult>(), varargs: false, options,	×
NEW 36	TypeExtensions.GetLogicalType<T1>(), TypeExtensions.GetLogicalType<T2>(),	×
NEW 37	TypeExtensions.GetLogicalType<T3>(), TypeExtensions.GetLogicalType<T4>());	×
UNCOV 38	}	×
39
40	private unsafe void RegisterScalarMethod(string name, Action<IReadOnlyList<IDuckDBDataReader>, IDuckDBDataWriter, ulong> action, DuckDBLogicalType returnType,
41	bool varargs, ScalarFunctionOptions? options, params DuckDBLogicalType[] parameterTypes)
42	{
43	var function = NativeMethods.ScalarFunction.DuckDBCreateScalarFunction();	90✔
44	NativeMethods.ScalarFunction.DuckDBScalarFunctionSetName(function, name);	90✔
45
46	if (varargs)	90✔
47	{
48	if (parameterTypes.Length != 1)	24!
49	{
50	throw new InvalidOperationException("Cannot use params with multiple parameters");	×
51	}
52
53	NativeMethods.ScalarFunction.DuckDBScalarFunctionSetVarargs(function, parameterTypes[0]);	24✔
54	parameterTypes[0].Dispose();	24✔
55	}
56	else
57	{
58	foreach (var type in parameterTypes)	318✔
59	{
60	NativeMethods.ScalarFunction.DuckDBScalarFunctionAddParameter(function, type);	93✔
61	type.Dispose();	93✔
62	}
63	}
64
65	// Functions with parameters default to pure; parameterless functions (e.g. random()) default to volatile
66	var defaultPure = parameterTypes.Length > 0;	90✔
67	if (!(options?.IsPureFunction ?? defaultPure))	90✔
68	{
69	NativeMethods.ScalarFunction.DuckDBScalarFunctionSetVolatile(function);	15✔
70	}
71
72	if (options?.HandlesNulls == true)	90✔
73	{
74	NativeMethods.ScalarFunction.DuckDBScalarFunctionSetSpecialHandling(function);	18✔
75	}
76
77	NativeMethods.ScalarFunction.DuckDBScalarFunctionSetReturnType(function, returnType);	90✔
78	NativeMethods.ScalarFunction.DuckDBScalarFunctionSetFunction(function, &ScalarFunctionCallback);	90✔
79
80	var info = new ScalarFunctionInfo(returnType, action);	90✔
81
82	NativeMethods.ScalarFunction.DuckDBScalarFunctionSetExtraInfo(function, info.ToHandle(), &DestroyExtraInfo);	90✔
83
84	var state = NativeMethods.ScalarFunction.DuckDBRegisterScalarFunction(NativeConnection, function);	90✔
85
86	NativeMethods.ScalarFunction.DuckDBDestroyScalarFunction(ref function);	90✔
87
88	if (!state.IsSuccess())	90!
89	{
90	throw new InvalidOperationException($"Error registering user defined scalar function: {name}");	×
91	}
92	}	90✔
93
94	[UnmanagedCallersOnly(CallConvs = [typeof(CallConvCdecl)])]
95	private static void ScalarFunctionCallback(IntPtr info, IntPtr chunk, IntPtr outputVector)
96	{
97	VectorDataReaderBase[] readers = [];	246✔
98	VectorDataWriterBase? writer = null;	246✔
99
100	try
101	{
102	var dataChunk = new DuckDBDataChunk(chunk);	246✔
103
104	var chunkSize = NativeMethods.DataChunks.DuckDBDataChunkGetSize(dataChunk);	246✔
105	var handle = GCHandle.FromIntPtr(NativeMethods.ScalarFunction.DuckDBScalarFunctionGetExtraInfo(info));	246✔
106
107	if (handle.Target is not ScalarFunctionInfo functionInfo)	246!
108	{
109	throw new InvalidOperationException("User defined scalar function execution failed. Function extra info is null");	×
110	}
111
112	readers = new VectorDataReaderBase[NativeMethods.DataChunks.DuckDBDataChunkGetColumnCount(dataChunk)];	246✔
113
114	for (var index = 0; index < readers.Length; index++)	1,206✔
115	{
116	var vector = NativeMethods.DataChunks.DuckDBDataChunkGetVector(dataChunk, index);	357✔
117	using var logicalType = NativeMethods.Vectors.DuckDBVectorGetColumnType(vector);	357✔
118	readers[index] = VectorDataReaderFactory.CreateReader(vector, logicalType);	357✔
119	}
120
121	writer = VectorDataWriterFactory.CreateWriter(outputVector, functionInfo.ReturnType);	246✔
122
123	functionInfo.Action(readers, writer, chunkSize);	246✔
124	}	228✔
125	catch (Exception ex)	18✔
126	{
127	NativeMethods.ScalarFunction.DuckDBScalarFunctionSetError(info, ex.Message);	18✔
128	}	18✔
129	finally
130	{
131	foreach (var reader in readers)	1,206✔
132	{
133	reader.Dispose();	357✔
134	}
135
136	writer?.Dispose();	246✔
137	}	246✔
138	}	246✔
139
140	[UnmanagedCallersOnly(CallConvs = [typeof(CallConvCdecl)])]
141	private static void DestroyExtraInfo(IntPtr pointer) => pointer.FreeHandle();	285✔
142	}

Giorgi / DuckDB.NET / 22734550158

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