feat(gen-shacl): add --message-template for sh:message on property shapes

packages/linkml/src/linkml/generators/shaclgen.py

@@ -84,6 +84,25 @@ class ShaclGenerator(Generator):
     Conforms to :rfc:`5646` (BCP 47).
     """
 
+    message_template: str | None = None
+    """Template for ``sh:message`` on property shapes.
+
+    When set, each property shape receives an ``sh:message`` literal built from
+    this template.  The following placeholders are expanded:
+
+    * ``{name}`` — the slot name (underscore-separated LinkML name)
+    * ``{title}`` — the slot title (human-readable), falls back to *name*
+    * ``{description}`` — the slot description, falls back to empty string
+    * ``{comments}`` — the slot comments joined with ``; ``, falls back to empty string
+    * ``{class}`` — the enclosing class name
+    * ``{path}``  — the property IRI (compact or full)
+
+    Example: ``"Validation of {name} failed!"`` →
+    ``sh:message "Validation of has_speed failed!"``
+
+    If ``default_language`` is also set the literal is language-tagged.
+    """
+
     generatorname = os.path.basename(__file__)
     generatorversion = "0.0.1"
     valid_formats = ["ttl"]
@@ -136,6 +155,7 @@ def _resolve_language(self, element=None) -> str | None:
 
     def __post_init__(self) -> None:
         super().__post_init__()
+        self.message_template = (self.message_template or "").strip() or None
         self.generate_header()
 
     def generate_header(self) -> str:
@@ -235,6 +255,25 @@ def prop_pv_text(p, v):
                 order += 1
                 prop_pv_text(SH.name, s.title)
                 prop_pv_text(SH.description, s.description)
+
+                # sh:message from template
+                if self.message_template is not None:
+                    try:
+                        msg_text = self.message_template.format(
+                            name=s.name,
+                            title=s.title or s.name,
+                            description=s.description or "",
+                            comments="; ".join(s.comments) if s.comments else "",
+                            **{"class": c.name},
+                            path=str(slot_uri),
+                        ).strip()
+                    except (KeyError, IndexError, ValueError) as exc:
+                        raise ValueError(
+                            f"Invalid placeholder {exc} in --message-template. "
+                            f"Allowed: {{name}}, {{title}}, {{description}}, {{comments}}, {{class}}, {{path}}"
+                        ) from None
+                    if msg_text:
+                        prop_pv_text(SH.message, msg_text)
                 # minCount
                 if s.minimum_cardinality:
                     prop_pv_literal(SH.minCount, s.minimum_cardinality)
@@ -612,6 +651,18 @@ def add_simple_data_type(func: Callable, r: ElementName) -> None:
         "language tag."
     ),
 )
+@click.option(
+    "--message-template",
+    default=None,
+    show_default=True,
+    help=(
+        "Template string for sh:message on each property shape. "
+        "Placeholders: {name} (slot name), {title} (slot title or name), "
+        "{description} (slot description), {comments} (slot comments joined with '; '), "
+        "{class} (class name), {path} (property IRI). "
+        'Example: "{name} ({class}): {description} [{comments}]"'
+    ),
+)
 @click.version_option(__version__, "-V", "--version")
 def cli(yamlfile, **args):
     """Generate SHACL turtle from a LinkML model"""

tests/linkml/test_generators/test_shaclgen.py

@@ -1192,6 +1192,34 @@ def _build_shacl_lang_schema():
     return sb.schema
 
 
+def _build_message_test_schema():
+    """Build a schema for sh:message testing (includes a second slot without title)."""
+    sb = SchemaBuilder()
+    sb.add_slot(
+        SlotDefinition(
+            "vehicle_name",
+            range="string",
+            description="The vehicle name.",
+            title="Name",
+            required=True,
+        )
+    )
+    sb.add_slot(
+        SlotDefinition(
+            "speed",
+            range="integer",
+            description="Speed in km/h.",
+        )
+    )
+    sb.add_class(
+        "Vehicle",
+        slots=["vehicle_name", "speed"],
+        description="A road vehicle.",
+    )
+    sb.add_defaults()
+    return sb.schema
+
+
 def _parse_shacl(schema, **kwargs):
     shacl = ShaclGenerator(schema, mergeimports=False, **kwargs).serialize()
     g = rdflib.Graph()
@@ -1380,3 +1408,204 @@ def test_shacl_default_language_in_language_bcp47_warning(caplog):
     labels = list(g.objects(EX.Vehicle, RDFS.label))
     assert any(lit.language == "toolongtag" for lit in labels)
     assert any("in_language" in rec.message and "toolongtag" in rec.message for rec in caplog.records)
+
+
+# ---------------------------------------------------------------------------
+# --message-template tests
+# ---------------------------------------------------------------------------
+
+
+def test_message_template_basic():
+    """--message-template emits sh:message on every property shape."""
+    schema = _build_message_test_schema()
+    g = _parse_shacl(schema, message_template="Validation of {name} failed!")
+
+    vehicle_shape = EX.Vehicle
+
+    msgs = _get_prop_objects(g, vehicle_shape, EX.vehicle_name, SH.message)
+    assert Literal("Validation of vehicle_name failed!") in msgs
+
+    msgs = _get_prop_objects(g, vehicle_shape, EX.speed, SH.message)
+    assert Literal("Validation of speed failed!") in msgs
+
+
+def test_message_template_title_placeholder():
+    """{title} expands to slot title, falling back to slot name."""
+    schema = _build_message_test_schema()
+    g = _parse_shacl(schema, message_template="{title} is invalid")
+
+    vehicle_shape = EX.Vehicle
+
+    # vehicle_name has title="Name"
+    msgs = _get_prop_objects(g, vehicle_shape, EX.vehicle_name, SH.message)
+    assert Literal("Name is invalid") in msgs
+
+    # speed has no title → falls back to slot name
+    msgs = _get_prop_objects(g, vehicle_shape, EX.speed, SH.message)
+    assert Literal("speed is invalid") in msgs
+
+
+def test_message_template_class_placeholder():
+    """{class} expands to the enclosing class name."""
+    schema = _build_message_test_schema()
+    g = _parse_shacl(schema, message_template="{class}.{name} constraint violated")
+
+    vehicle_shape = EX.Vehicle
+
+    msgs = _get_prop_objects(g, vehicle_shape, EX.vehicle_name, SH.message)
+    assert Literal("Vehicle.vehicle_name constraint violated") in msgs
+
+
+def test_message_template_description_placeholder():
+    """{description} expands to the slot description, empty string when absent."""
+    schema = _build_message_test_schema()
+    g = _parse_shacl(schema, message_template="{name} ({class}): {description}")
+
+    vehicle_shape = EX.Vehicle
+
+    # vehicle_name has description="The vehicle name."
+    msgs = _get_prop_objects(g, vehicle_shape, EX.vehicle_name, SH.message)
+    assert Literal("vehicle_name (Vehicle): The vehicle name.") in msgs
+
+    # speed has description="Speed in km/h."
+    msgs = _get_prop_objects(g, vehicle_shape, EX.speed, SH.message)
+    assert Literal("speed (Vehicle): Speed in km/h.") in msgs
+
+
+def test_message_template_description_fallback_empty():
+    """{description} falls back to empty string when slot has no description."""
+    sb = SchemaBuilder()
+    sb.add_slot(SlotDefinition("bare_slot", range="string"))
+    sb.add_class("Thing", slots=["bare_slot"])
+    sb.add_defaults()
+    g = _parse_shacl(sb.schema, message_template="{name}: {description}")
+
+    msgs = _get_prop_objects(g, EX.Thing, EX.bare_slot, SH.message)
+    assert Literal("bare_slot: ") in msgs
+
+
+def test_message_template_comments_placeholder():
+    """{comments} expands to slot comments joined with '; '."""
+    sb = SchemaBuilder()
+    sb.add_slot(
+        SlotDefinition(
+            "wind_speed",
+            range="float",
+            description="Wind speed in metres per second.",
+            comments=["ISO 34503:2023, Section 10.2.3"],
+        )
+    )
+    sb.add_class("Weather", slots=["wind_speed"])
+    sb.add_defaults()
+    g = _parse_shacl(sb.schema, message_template="{name} ({class}): {description} [{comments}]")
+
+    msgs = _get_prop_objects(g, EX.Weather, EX.wind_speed, SH.message)
+    assert Literal("wind_speed (Weather): Wind speed in metres per second. [ISO 34503:2023, Section 10.2.3]") in msgs
+
+
+def test_message_template_comments_multiple():
+    """{comments} joins multiple comments with '; '."""
+    sb = SchemaBuilder()
+    sb.add_slot(
+        SlotDefinition(
+            "temperature",
+            range="float",
+            comments=["ISO 34503:2023, Section 10.2", "Unit: Celsius"],
+        )
+    )
+    sb.add_class("Weather", slots=["temperature"])
+    sb.add_defaults()
+    g = _parse_shacl(sb.schema, message_template="{comments}")
+
+    msgs = _get_prop_objects(g, EX.Weather, EX.temperature, SH.message)
+    assert Literal("ISO 34503:2023, Section 10.2; Unit: Celsius") in msgs
+
+
+def test_message_template_comments_fallback_empty():
+    """{comments} falls back to empty string when slot has no comments."""
+    sb = SchemaBuilder()
+    sb.add_slot(SlotDefinition("bare_slot", range="string"))
+    sb.add_class("Thing", slots=["bare_slot"])
+    sb.add_defaults()
+    g = _parse_shacl(sb.schema, message_template="{name}: {comments}")
+
+    msgs = _get_prop_objects(g, EX.Thing, EX.bare_slot, SH.message)
+    assert Literal("bare_slot: ") in msgs
+
+
+def test_no_message_template_no_sh_message():
+    """Without --message-template, no sh:message is emitted (backward-compat)."""
+    schema = _build_message_test_schema()
+    g = _parse_shacl(schema)
+
+    vehicle_shape = EX.Vehicle
+
+    msgs = _get_prop_objects(g, vehicle_shape, EX.vehicle_name, SH.message)
+    assert msgs == []
+
+    msgs = _get_prop_objects(g, vehicle_shape, EX.speed, SH.message)
+    assert msgs == []
+
+
+def test_message_template_invalid_placeholder_raises():
+    """An invalid placeholder in --message-template raises ValueError."""
+    import pytest
+
+    schema = _build_message_test_schema()
+    with pytest.raises(ValueError, match="Invalid placeholder"):
+        _parse_shacl(schema, message_template="Error: {invalid}")
+
+
+def test_message_template_positional_placeholder_raises():
+    """Positional placeholders like {0} raise ValueError."""
+    import pytest
+
+    schema = _build_message_test_schema()
+    with pytest.raises(ValueError, match="Invalid placeholder"):
+        _parse_shacl(schema, message_template="Error: {0}")
+
+
+def test_message_template_format_spec_raises():
+    """Format specs like {name:d} raise ValueError."""
+    import pytest
+
+    schema = _build_message_test_schema()
+    with pytest.raises(ValueError, match="Invalid placeholder"):
+        _parse_shacl(schema, message_template="Error: {name:d}")
+
+
+def test_message_template_empty_string_treated_as_none():
+    """An empty message_template is normalised to None (no sh:message)."""
+    schema = _build_message_test_schema()
+    g = _parse_shacl(schema, message_template="")
+
+    vehicle_shape = EX.Vehicle
+    msgs = _get_prop_objects(g, vehicle_shape, EX.vehicle_name, SH.message)
+    assert msgs == []
+
+
+def test_message_template_whitespace_only_treated_as_none():
+    """A whitespace-only message_template is normalised to None (no sh:message)."""
+    schema = _build_message_test_schema()
+    g = _parse_shacl(schema, message_template="   ")
+
+    vehicle_shape = EX.Vehicle
+    msgs = _get_prop_objects(g, vehicle_shape, EX.vehicle_name, SH.message)
+    assert msgs == []
+
+
+def test_message_template_with_default_language():
+    """sh:message is language-tagged when both --message-template and --default-language are set."""
+    schema = _build_message_test_schema()
+    g = _parse_shacl(
+        schema,
+        message_template="Validation of {name} failed!",
+        default_language="en",
+    )
+
+    vehicle_shape = EX.Vehicle
+    msgs = _get_prop_objects(g, vehicle_shape, EX.vehicle_name, SH.message)
+    assert Literal("Validation of vehicle_name failed!", lang="en") in msgs
+
+    # Verify the message is NOT a plain literal
+    assert Literal("Validation of vehicle_name failed!") not in msgs