fix(model): Round namespace versions

Fixes #417.

capellambse/_namespaces.py

@@ -35,6 +35,20 @@ class Plugin:
     version: str | tuple[str, str] | None = None
     viewpoint: str | None = None
 
+    version_precision: int = 1
+    """Number of significant parts in the version number for namespaces.
+
+    When generating a versioned namespace URL from a Plugin, only this
+    many digits will be taken from the activated viewpoint. This allows
+    reusing the same namespace across subsequent minor plugin releases.
+
+    Example: A version of "1.2.3" with precision set to 2 will result in
+    the namespace version "1.2.0" being used.
+
+    Note that the used version number will always be padded with zeroes
+    to as many parts as there are in the original version number.
+    """
+
     def __post_init__(self) -> None:
         if self.version is not None and self.viewpoint is None:
             raise TypeError("Versioned plugins require a viewpoint")

capellambse/loader/core.py

@@ -134,6 +134,34 @@ def _unquote_ref(ref: str) -> str:
     return ref
 
 
+def _round_version(v: str, prec: int) -> str:
+    """Round a version number.
+
+    Parameters
+    ----------
+    v
+        The version number.
+    prec
+        Precision to round to, i.e. the number of leading non-zero
+        parts. Remaining parts will be set to zero.
+
+    Returns
+    -------
+    str
+        The rounded version number.
+    """
+    assert prec > 0
+    pos = dots = 0
+    while pos < len(v) and dots < prec:
+        try:
+            pos = v.index(".", pos) + 1
+        except ValueError:
+            return v
+        else:
+            dots += 1
+    return v[:pos] + re.sub(r"[^.]+", "0", v[pos:])
+
+
 class FragmentType(enum.Enum):
     """The type of an XML fragment."""
 
@@ -319,6 +347,9 @@ def update_namespaces(self, viewpoints: cabc.Mapping[str, str]) -> None:
                     raise CorruptModelError(
                         f"Viewpoint not activated: {plugin.viewpoint}"
                     )
+                vp_version = _round_version(
+                    vp_version, plugin.version_precision
+                )
                 uri += f"/{vp_version}"
 
             assert new_nsmap.get(ns) in (None, uri)

tests/test_model_loading.py

@@ -595,3 +595,15 @@ def test_model_diagram_visible_nodes_can_be_accessed_when_a_cache_was_specified(
     model = capellambse.MelodyModel(TEST_MODEL_5_0, diagram_cache=tmp_path)
 
     assert model.diagrams[0].nodes
+
+
+def test_updated_namespaces_use_rounded_versions(
+    model_5_2: capellambse.MelodyModel,
+):
+    model_5_2._loader.update_namespaces()
+
+    assert model_5_2.info.capella_version == "5.2.0"
+    nsver = model_5_2._element.nsmap[
+        "org.polarsys.capella.core.data.capellacommon"
+    ].rsplit("/", 1)[-1]
+    assert nsver == "5.0.0"