Fix static_analysis: off interpreted as boolean false (#12015)

YAML interprets unquoted `on`/`off` as booleans. Add `static_analysis`
as a typed field to config dataclasses with __post_init__ coercion so
the manifest serializes the string value, not a boolean.

Author: b-per

.changes/unreleased/Fixes-20260219-120000.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: 'Fix `static_analysis: off` being interpreted as boolean `false` instead of string `"off"` in manifest.json'
+time: 2026-02-19T12:00:00.000000-05:00
+custom:
+    Author: b-per
+    Issue: "12015"

core/dbt/artifacts/resources/v1/config.py

@@ -72,6 +72,13 @@ class NodeAndTestConfig(BaseConfig):
         default=None,
         metadata=CompareBehavior.Exclude.meta(),
     )
+    static_analysis: Optional[str] = None
+
+    def __post_init__(self):
+        # YAML interprets unquoted `on`/`off` as booleans; coerce back to strings
+        # so that `static_analysis: off` serializes as "off", not false.
+        if isinstance(self.static_analysis, bool):
+            self.static_analysis = "on" if self.static_analysis else "off"
 
 
 @dataclass
@@ -129,6 +136,7 @@ class NodeConfig(NodeAndTestConfig):
     concurrent_batches: Any = None
 
     def __post_init__(self):
+        super().__post_init__()
         # we validate that node_color has a suitable value to prevent dbt-docs from crashing
         if self.docs.node_color:
             node_color = self.docs.node_color

core/dbt/artifacts/resources/v1/source_definition.py

@@ -25,6 +25,11 @@ class SourceConfig(BaseConfig):
     loaded_at_query: Optional[str] = None
     meta: Dict[str, Any] = field(default_factory=dict, metadata=MergeBehavior.Update.meta())
     tags: List[str] = field(default_factory=list)
+    static_analysis: Optional[str] = None
+
+    def __post_init__(self):
+        if isinstance(self.static_analysis, bool):
+            self.static_analysis = "on" if self.static_analysis else "off"
 
 
 @dataclass

core/dbt/artifacts/resources/v1/unit_test_definition.py

@@ -21,6 +21,11 @@ class UnitTestConfig(BaseConfig):
         metadata=MergeBehavior.Update.meta(),
     )
     enabled: bool = True
+    static_analysis: Optional[str] = None
+
+    def __post_init__(self):
+        if isinstance(self.static_analysis, bool):
+            self.static_analysis = "on" if self.static_analysis else "off"
 
 
 class UnitTestFormat(StrEnum):

tests/unit/contracts/graph/test_nodes_parsed.py

@@ -152,6 +152,47 @@ def test_config_same(unrendered_node_config_dict, func):
     assert ModelConfig.same_contents(unrendered_node_config_dict, value)
 
 
+class TestStaticAnalysisBoolCoercion:
+    """YAML interprets unquoted on/off as booleans. Ensure static_analysis
+    is always coerced to a string so manifest.json contains "off"/"on"
+    rather than false/true. See: https://github.com/dbt-labs/dbt-core/issues/12015"""
+
+    def test_false_coerced_to_off(self):
+        cfg = ModelConfig(static_analysis=False)
+        assert cfg.static_analysis == "off"
+
+    def test_true_coerced_to_on(self):
+        cfg = ModelConfig(static_analysis=True)
+        assert cfg.static_analysis == "on"
+
+    def test_string_off_unchanged(self):
+        cfg = ModelConfig(static_analysis="off")
+        assert cfg.static_analysis == "off"
+
+    def test_string_on_unchanged(self):
+        cfg = ModelConfig(static_analysis="on")
+        assert cfg.static_analysis == "on"
+
+    def test_string_unsafe_unchanged(self):
+        cfg = ModelConfig(static_analysis="unsafe")
+        assert cfg.static_analysis == "unsafe"
+
+    def test_none_default(self):
+        cfg = ModelConfig()
+        assert cfg.static_analysis is None
+
+    def test_serializes_as_string(self):
+        cfg = ModelConfig(static_analysis=False)
+        d = cfg.to_dict(omit_none=True)
+        assert d["static_analysis"] == "off"
+
+    def test_source_config_coercion(self):
+        cfg = SourceConfig(static_analysis=False)
+        assert cfg.static_analysis == "off"
+        cfg2 = SourceConfig(static_analysis=True)
+        assert cfg2.static_analysis == "on"
+
+
 @pytest.fixture
 def base_parsed_model_dict():
     return {