fix: preserve configuration completion context

crates/config-source-wasm/src/lib.rs

@@ -101,20 +101,24 @@ pub fn complete_current(
         let utf8_byte_offset = utf16_to_utf8_offset(&source, utf16_offset)?;
         let result = session_environment(snapshot.clone())
             .complete_config(&entrypoint, &source, utf8_byte_offset, explicit)
-            .map_err(|error| JsValue::from_str(&format!("{error:?}")))?
-            .map(|result| WasmCompletionResult {
-                from: result.from,
-                items: result
-                    .items
-                    .into_iter()
-                    .map(|item| WasmCompletionItem {
-                        label: item.label,
-                        kind: format!("{:?}", item.kind).to_lowercase(),
-                        detail: item.detail,
-                        priority: item.priority,
-                    })
-                    .collect(),
-            });
+            .map_err(|error| JsValue::from_str(&format!("{error:?}")))?;
+        let result = result
+            .map(|result| {
+                Ok::<WasmCompletionResult, JsValue>(WasmCompletionResult {
+                    from: utf8_to_utf16_offset(&source, result.from)?,
+                    items: result
+                        .items
+                        .into_iter()
+                        .map(|item| WasmCompletionItem {
+                            label: item.label,
+                            kind: format!("{:?}", item.kind).to_lowercase(),
+                            detail: item.detail,
+                            priority: item.priority,
+                        })
+                        .collect(),
+                })
+            })
+            .transpose()?;
         encode(result)
     })
 }
@@ -177,6 +181,16 @@ fn utf16_to_utf8_offset(source: &str, utf16_offset: usize) -> Result<usize, JsVa
     }
 }
 
+fn utf8_to_utf16_offset(source: &str, utf8_offset: usize) -> Result<usize, JsValue> {
+    if utf8_offset > source.len() {
+        return Err(JsValue::from_str("UTF-8 offset is outside the source"));
+    }
+    if !source.is_char_boundary(utf8_offset) {
+        return Err(JsValue::from_str("UTF-8 offset splits a character"));
+    }
+    Ok(source[..utf8_offset].encode_utf16().count())
+}
+
 fn decode<T: serde::de::DeserializeOwned>(value: JsValue) -> Result<T, JsValue> {
     from_value(value).map_err(|error| JsValue::from_str(&error.to_string()))
 }

crates/config-source/src/lib.rs

@@ -1203,6 +1203,9 @@ impl SnapshotEnvironment {
         {
             let mut member_source = format!("{WORKSPACE_CONFIG_SCHEMA_GLOBAL}.");
             member_source.push_str(&context.schema_path.join("."));
+            if !context.schema_path.is_empty() && context.from == utf8_byte_offset {
+                member_source.push('.');
+            }
             let mut completion = LanguageService::new(self).complete(
                 entrypoint.as_str(),
                 &member_source,
@@ -1961,6 +1964,31 @@ mod tests {
                 .iter()
                 .any(|item| item.label == "default_profile")
         );
+
+        let blank_nested_source = "{ profile = {  } } as WorkspaceConfigSchema";
+        let blank_nested_cursor = blank_nested_source.find("{  }").unwrap() + 2;
+        let blank_nested = environment
+            .complete_config(
+                &path("main.dcdl"),
+                blank_nested_source,
+                blank_nested_cursor,
+                true,
+            )
+            .unwrap()
+            .unwrap();
+        assert_eq!(blank_nested.from, blank_nested_cursor);
+        assert!(
+            blank_nested
+                .items
+                .iter()
+                .any(|item| item.label == "default_profile")
+        );
+        assert!(
+            !blank_nested
+                .items
+                .iter()
+                .any(|item| item.label == "profile")
+        );
     }
 
     #[test]