Use simplified upsert from yamltrip 0.6.0

nathanjmcdougall · nathanjmcdougall · commit 5424968300de · 2026-06-02T16:50:38.000+12:00
diff --git a/pyproject.toml b/pyproject.toml
@@ -61,7 +61,7 @@ dependencies = [
   "tomlkit>=0.13.3",
   "typer>=0.12.4",
   "typing-extensions>=3.10.0.0",
-  "yamltrip>=0.5.0",
+  "yamltrip>=0.6.0",
 ]
 scripts.usethis = "usethis.__main__:app"
 
diff --git a/src/usethis/_file/yaml/io_.py b/src/usethis/_file/yaml/io_.py
@@ -301,49 +301,30 @@ def _upsert_safe(
     *,
     exists_ok: bool = False,
 ) -> yamltrip.Document:
-    """Upsert a value into a yamltrip Document, handling empty documents."""
-    # For complex values (list/dict) where the key doesn't exist yet, add a
-    # null placeholder first then replace — this forces block-style output.
-    if isinstance(value, (list, dict)) and tuple(keys) not in doc:
-        try:
-            doc = doc.upsert(*keys, value=None)
-        except yamltrip.PatchError:
-            pass
-        else:
-            return doc.upsert(*keys, value=value)
+    """Upsert a value into a yamltrip Document.
 
+    A RoutingError means a key in the path passes through a non-mapping node. When
+    overwriting is allowed we prune the conflicting prefix and retry; otherwise we
+    translate it into a friendly YAMLValueAlreadySetError.
+    """
     try:
+        # Seed the leaf as null first, then write the value. Seeding forces
+        # complex values to render in block style (rather than flow style) and
+        # fully replaces any existing value at the path.
+        doc = doc.upsert(*keys, value=None)
         return doc.upsert(*keys, value=value)
-    except yamltrip.PatchError as err:
-        if not doc.source.strip():
-            # Empty document: bootstrap with a block-style seed then upsert.
-            # yamlpatch's Add operation requires an existing mapping node at the
-            # target route, so it cannot add keys to a truly empty document.
-            # We work around this by seeding with a throwaway sentinel key ("_")
-            # to create a root mapping, inserting the real content, then removing
-            # the sentinel.  The sentinel is safe because the document is empty
-            # (no user data to collide with).
-            # Tracking issue to remove this workaround:
-            # https://github.com/usethis-python/yamltrip/issues/34
-            doc = yamltrip.loads("_: null\n")
-            doc = doc.upsert(*keys, value=None)
-            doc = doc.upsert(*keys, value=value)
-            return doc.remove("_")
-        err_msg = str(err)
-        if (
-            "non-mapping route" in err_msg
-            or "expected mapping containing key" in err_msg
-        ):
-            if exists_ok:
-                # Remove the conflicting prefix and retry.
-                for i in range(len(keys) - 1, 0, -1):
-                    if tuple(keys[:i]) in doc:
-                        doc = doc.prune_remove(*keys[:i])
-                        return _upsert_safe(doc, keys, value, exists_ok=exists_ok)
-            # Trying to add a key under a non-mapping node.
-            # Find the longest existing prefix to report.
-            for i in range(len(keys) - 1, 0, -1):
-                if tuple(keys[:i]) in doc:
-                    msg = f"Configuration value '{print_keys(list(keys[:i]))}' is already set."
-                    raise YAMLValueAlreadySetError(msg) from err
-        raise
+    except yamltrip.RoutingError as err:
+        # A key along the path maps to a non-mapping node. Find the longest
+        # existing prefix: the node we collided with.
+        for i in range(len(keys) - 1, 0, -1):
+            if tuple(keys[:i]) in doc:
+                if exists_ok:
+                    # Overwrite: remove the conflicting prefix and retry.
+                    doc = doc.prune_remove(*keys[:i])
+                    return _upsert_safe(doc, keys, value, exists_ok=exists_ok)
+                msg = f"Configuration value '{print_keys(list(keys[:i]))}' is already set."
+                raise YAMLValueAlreadySetError(msg) from err
+        # A RoutingError always collides with an existing non-mapping prefix, so
+        # the loop above must have returned or raised.
+        msg = "RoutingError did not pass through an existing prefix."
+        raise AssertionError(msg) from err
diff --git a/tests/usethis/_file/yaml/test_yaml_io_.py b/tests/usethis/_file/yaml/test_yaml_io_.py
@@ -796,6 +796,54 @@ def relative_path(self) -> Path:
                 assert isinstance(manager._content, YAMLDocument)
                 assert manager._content.doc.root == {"items": ["a", "b"]}
 
+        def test_complex_value_clash_with_non_mapping(self, tmp_path: Path):
+            # Arrange
+            class MyYAMLFileManager(YAMLFileManager):
+                @property
+                @override
+                def relative_path(self) -> Path:
+                    return Path("my_yaml_file.yaml")
+
+            (tmp_path / "my_yaml_file.yaml").write_text("outer: value\n")
+
+            with change_cwd(tmp_path), MyYAMLFileManager() as manager:
+                manager.read_file()
+
+                # Act, Assert
+                with pytest.raises(
+                    YAMLValueAlreadySetError,
+                    match=r"Configuration value 'outer' is already set.",
+                ):
+                    manager.set_value(
+                        keys=["outer", "inner"],
+                        value=["a", "b"],
+                        exists_ok=False,
+                    )
+
+        def test_complex_value_clash_overwrite(self, tmp_path: Path):
+            # Arrange
+            class MyYAMLFileManager(YAMLFileManager):
+                @property
+                @override
+                def relative_path(self) -> Path:
+                    return Path("my_yaml_file.yaml")
+
+            (tmp_path / "my_yaml_file.yaml").write_text("outer: value\n")
+
+            with change_cwd(tmp_path), MyYAMLFileManager() as manager:
+                manager.read_file()
+
+                # Act
+                manager.set_value(
+                    keys=["outer", "inner"],
+                    value=["a", "b"],
+                    exists_ok=True,
+                )
+
+                # Assert
+                assert isinstance(manager._content, YAMLDocument)
+                assert manager._content.doc.root == {"outer": {"inner": ["a", "b"]}}
+
     class TestDelItem:
         def test_delete_single_item(self, tmp_path: Path):
             # Arrange
diff --git a/uv.lock b/uv.lock

Original file line number	Diff line number	Diff line change
`@@ -61,7 +61,7 @@ dependencies = [`
`61`	`61`	`"tomlkit>=0.13.3",`
`62`	`62`	`"typer>=0.12.4",`
`63`	`63`	`"typing-extensions>=3.10.0.0",`
`64`		`- "yamltrip>=0.5.0",`
	`64`	`+ "yamltrip>=0.6.0",`
`65`	`65`	`]`
`66`	`66`	`scripts.usethis = "usethis.__main__:app"`
`67`	`67`