ParamValue UINT8+bytes path; expand python-paramlist tests

Signed-off-by: Aleksandr Motsjonov <soswow@gmail.com>

Author: soswow

src/python-nanobind/MIGRATION_STATUS.md

@@ -9,13 +9,13 @@ Generated from the binding sources. The nanobind extension is `PyOpenImageIONano
 | `py_roi.cpp` | <code>ROI</code><br>Free functions:<br><ul><li><code>union</code></li><li><code>intersection</code></li><li><code>get_roi</code></li><li><code>get_roi_full</code></li><li><code>set_roi</code></li><li><code>set_roi_full</code></li></ul> |
 | `py_typedesc.cpp` | <code>TypeDesc</code><br>Enums: <code>BASETYPE</code>, <code>AGGREGATE</code>, <code>VECSEMANTICS</code><br>Module <code>Type*</code> constants |
 | `py_imagespec.cpp` | <code>ImageSpec</code> (bound methods/properties, typed <code>attribute</code> / buffer paths via shared helpers). |
+| `py_paramvalue.cpp` | <code>ParamValue</code>, <code>ParamValueList</code><br>Enum: <code>Interp</code> |
 
 ## Migrated — partial (gaps or intentional deltas vs pybind)
 
 | Source file | Migrated (vs pybind) | Missing or divergent (vs pybind) |
 | --- | --- | --- |
 | `py_oiio.cpp` (`_OpenImageIO` module) | <ul><li><code>attribute</code> (one-arg and typed)</li><li><code>get_int_attribute</code></li><li><code>get_float_attribute</code></li><li><code>get_string_attribute</code></li><li><code>getattribute</code></li><li><code>__version__</code></li></ul> | <ul><li><code>geterror</code></li><li><code>get_bytes_attribute</code></li><li>Module <code>set_colorspace</code> (helper taking <code>ImageSpec</code> — the instance method is on <code>ImageSpec</code> in nanobind)</li><li><code>set_colorspace_rec709_gamma</code></li><li><code>equivalent_colorspace</code></li><li><code>is_imageio_format_name</code></li><li><code>AutoStride</code></li><li><code>openimageio_version</code>, <code>VERSION</code>, <code>VERSION_STRING</code>, <code>VERSION_MAJOR</code>, <code>VERSION_MINOR</code>, <code>VERSION_PATCH</code>, <code>INTRO_STRING</code></li><li>Optional: stack traces when <code>OPENIMAGEIO_DEBUG_PYTHON</code> is set (<code>Sysutil</code>)</li><li><code>make_pyobject</code>: no pybind-style <code>debugfmt</code> when the type is unhandled (returns default quietly)</li></ul> |
-| `py_paramvalue.cpp` | Types: <code>ParamValue</code>, <code>ParamValueList</code><br>Enum: <code>Interp</code><br>Rest of the bound surface matches pybind. | <code>paramvalue_from_pyobject</code>: no pybind-style path for <code>UINT8</code> + <code>bytes</code> with <code>type.arraylen</code> (incl. inferred length from <code>bytes</code> size). |
 | `__init__.py` (package) | Env / DLL path setup, <code>from ._OpenImageIO import *</code>, version docstring. | <strong>TODO:</strong> Python CLI entry-point trampolines when the install layout matches the full wheel. |
 
 ---

src/python-nanobind/py_paramvalue.cpp

@@ -96,6 +96,19 @@ paramvalue_from_pyobject(string_view name, TypeDesc type, int nvalues,
                 converted.emplace_back(val);
             pv.init(name, type, nvalues, interp, converted.data());
         }
+    } else if (type.basetype == TypeDesc::UINT8 && type.arraylen
+               && nb::isinstance<nb::bytes>(obj)) {
+        TypeDesc t     = type;
+        nb::bytes b    = nb::cast<nb::bytes>(obj);
+        const std::string s(b.c_str(), b.size());
+        if (t.arraylen < 0)
+            t.arraylen = static_cast<int>(s.size()) / nvalues;
+        if (t.arraylen * nvalues == static_cast<int>(s.size())) {
+            std::vector<uint8_t> vals(
+                reinterpret_cast<const uint8_t*>(s.data()),
+                reinterpret_cast<const uint8_t*>(s.data()) + s.size());
+            pv.init(name, t, nvalues, interp, vals.data());
+        }
     } else if (type.basetype == TypeDesc::UINT8) {
         std::vector<uint8_t> vals;
         if (PyOpenImageIO::py_to_stdvector(vals, obj)

testsuite/python-paramlist/ref/out.txt

@@ -8,6 +8,9 @@ Testing individual ParamValue:
   item g color (0.25, 0.5, 0.75)
   item ucarr uint8[10] [49 50 51  0  0 97 98 99  1 88]
   item bts uint8[10] [49 50 51  0  0 97 98 99  1 88]
+  item u8unsized uint8[10] [49 50 51 52 53 54 55 56 57 48]
+  item u8fix_n2 uint8[2] [ 97  98  99 100 101 102]
+  item u8var_n2 uint8[4] [49 50 51 52 53 54 55 56]
 
 Testing ParamValueList:
 pl length is 9

testsuite/python-paramlist/src/test_paramlist.py

@@ -50,8 +50,41 @@ def print_param_list(pl: oiio.ParamValueList) :
     # Construct from numpy byte array
     pv = oiio.ParamValue("ucarr", "uint8[10]", numpy.array([49, 50, 51, 0, 0, 97, 98, 99, 1, 88], dtype='B'))
     print_param_value(pv)
-    # Construct from bytes
+
+    # C++: paramvalue_from_pyobject UINT8 + Python bytes (pybind parity). Copy raw
+    # bytes when type.arraylen is set, len(bytes) == arraylen*nvalues, and if
+    # arraylen<0 (uint8[]), set arraylen = len(bytes)//nvalues first.
+
+    # Setup: fixed width uint8[10], single value — exercises bytes special case without inference.
     pv = oiio.ParamValue("bts", "uint8[10]", b'123\x00\x00abc\x01X')
+    # Check: name/type/value match ref; bytes land as uint8[10] (10*1==10).
+    print_param_value(pv)
+
+    # Setup: unsized uint8[], nvalues 1 — must infer arraylen 10 from len(bytes).
+    pv = oiio.ParamValue("u8unsized", oiio.TypeDesc("uint8[]"), b"1234567890")
+    # Check: type prints as uint8[10] (inferred) and payload matches the string bytes.
+    print_param_value(pv)
+
+    # Setup: uint8[2] with nvalues=3, 6 bytes — fixed arraylen, multiple ParamValue "values".
+    pv = oiio.ParamValue(
+        "u8fix_n2",
+        oiio.TypeDesc("uint8[2]"),
+        3,
+        oiio.Interp.CONSTANT,
+        b"abcdef",
+    )
+    # Check: 2*3==6; same special-case path, no arraylen<0 branch.
+    print_param_value(pv)
+
+    # Setup: unsized uint8[], nvalues=2, 8 bytes — infer arraylen=4, then 4*2==8.
+    pv = oiio.ParamValue(
+        "u8var_n2",
+        oiio.TypeDesc("uint8[]"),
+        2,
+        oiio.Interp.CONSTANT,
+        b"12345678",
+    )
+    # Check: type uint8[4] with 2 nvalues; exercises inference with nvalues>1.
     print_param_value(pv)
 
     print ("")