config: complete virtual tree editor contract

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

@@ -1,9 +1,102 @@
 use config_source::{
-    ConfigTreeSnapshot, EvaluationResult, SnapshotEnvironment, ToolchainContract, VirtualPath,
+    ConfigTreeChange, ConfigTreeSnapshot, EvaluationResult, SnapshotEnvironment, ToolchainContract,
+    VirtualPath,
 };
 use serde_wasm_bindgen::{Serializer, from_value};
+use std::cell::RefCell;
 use wasm_bindgen::prelude::*;
 
+thread_local! {
+    static SESSION: RefCell<Option<ConfigTreeSnapshot>> = const { RefCell::new(None) };
+}
+
+#[wasm_bindgen]
+pub fn set_snapshot(snapshot: JsValue) -> Result<(), JsValue> {
+    let snapshot: ConfigTreeSnapshot = decode(snapshot)?;
+    SESSION.with(|session| session.replace(Some(snapshot)));
+    Ok(())
+}
+
+#[wasm_bindgen]
+pub fn apply_changes(changes: JsValue) -> Result<JsValue, JsValue> {
+    let changes: Vec<ConfigTreeChange> = decode(changes)?;
+    SESSION.with(|session| {
+        let mut session = session.borrow_mut();
+        let snapshot = session
+            .as_ref()
+            .ok_or_else(|| JsValue::from_str("config source snapshot is not initialized"))?
+            .apply(&changes)
+            .map_err(js_error)?;
+        *session = Some(snapshot.clone());
+        encode(snapshot)
+    })
+}
+
+#[wasm_bindgen]
+pub fn evaluate_current(contract: JsValue) -> Result<JsValue, JsValue> {
+    let contract: ToolchainContract = decode(contract)?;
+    SESSION.with(|session| {
+        let session = session.borrow();
+        let snapshot = session
+            .as_ref()
+            .ok_or_else(|| JsValue::from_str("config source snapshot is not initialized"))?;
+        encode(
+            SnapshotEnvironment::new(snapshot.clone())
+                .evaluate_contract(&contract)
+                .map_err(|diagnostics| {
+                    encode(&diagnostics).unwrap_or_else(|_| JsValue::from_str("evaluation failed"))
+                })?,
+        )
+    })
+}
+
+#[derive(serde::Serialize)]
+struct WasmCompletionResult {
+    from: usize,
+    items: Vec<WasmCompletionItem>,
+}
+
+#[derive(serde::Serialize)]
+struct WasmCompletionItem {
+    label: String,
+    kind: String,
+    detail: Option<String>,
+    priority: i32,
+}
+
+#[wasm_bindgen]
+pub fn complete_current(
+    entrypoint: String,
+    source: String,
+    utf8_byte_offset: usize,
+    explicit: bool,
+) -> Result<JsValue, JsValue> {
+    let entrypoint = VirtualPath::parse(entrypoint).map_err(js_error)?;
+    SESSION.with(|session| {
+        let session = session.borrow();
+        let snapshot = session
+            .as_ref()
+            .ok_or_else(|| JsValue::from_str("config source snapshot is not initialized"))?;
+        let result = SnapshotEnvironment::new(snapshot.clone())
+            .complete(&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(),
+            });
+        encode(result)
+    })
+}
+
 #[wasm_bindgen]
 pub fn evaluate_snapshot(snapshot: JsValue, contract: JsValue) -> Result<JsValue, JsValue> {
     let snapshot: ConfigTreeSnapshot = decode(snapshot)?;

crates/workspace-server/src/config_source.rs

@@ -33,6 +33,7 @@ pub struct ConfigCommitRequest {
     pub base_digest: String,
     pub changes: Vec<ConfigTreeChange>,
     pub entrypoints: Vec<VirtualPath>,
+    pub toolchain_fingerprint: String,
 }
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
@@ -65,6 +66,17 @@ impl SqliteWorkspaceStore {
                 current.snapshot.revision
             )));
         }
+        let expected_contract = ToolchainContract::new(
+            DEFAULT_SCHEMA_VERSION,
+            request.entrypoints.clone(),
+            DEFAULT_IMPORT_POLICY_VERSION,
+        );
+        if expected_contract.fingerprint != request.toolchain_fingerprint {
+            return Err(config_conflict(format!(
+                "toolchain fingerprint mismatch; current fingerprint is {}",
+                expected_contract.fingerprint
+            )));
+        }
         evaluate_candidate(current, &request.changes, request.entrypoints.clone())
     }
 
@@ -378,6 +390,12 @@ mod tests {
                         content: "{ broken = ; }".into(),
                     }],
                     entrypoints: vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                    toolchain_fingerprint: ToolchainContract::new(
+                        DEFAULT_SCHEMA_VERSION,
+                        vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                        DEFAULT_IMPORT_POLICY_VERSION,
+                    )
+                    .fingerprint,
                 },
             )
             .unwrap_err();
@@ -402,6 +420,12 @@ mod tests {
                         content: "{ answer = 42; }".into(),
                     }],
                     entrypoints: vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                    toolchain_fingerprint: ToolchainContract::new(
+                        DEFAULT_SCHEMA_VERSION,
+                        vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                        DEFAULT_IMPORT_POLICY_VERSION,
+                    )
+                    .fingerprint,
                 },
             )
             .unwrap();
@@ -426,6 +450,12 @@ mod tests {
                 content: "{ answer = 42; }".into(),
             }],
             entrypoints: vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+            toolchain_fingerprint: ToolchainContract::new(
+                DEFAULT_SCHEMA_VERSION,
+                vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                DEFAULT_IMPORT_POLICY_VERSION,
+            )
+            .fingerprint,
         };
         let candidate = store
             .evaluate_workspace_config_candidate("w-config", &request)
@@ -439,6 +469,31 @@ mod tests {
         assert!(matches!(error, Error::WorkspaceConfigConflict(_)));
     }
 
+    #[tokio::test]
+    async fn commit_rejects_mismatched_toolchain_fingerprint() {
+        let store = SqliteWorkspaceStore::in_memory().unwrap();
+        store.upsert_workspace(&workspace()).await.unwrap();
+        let empty = ConfigTreeSnapshot::empty();
+        let error = store
+            .evaluate_and_commit_workspace_config(
+                "w-config",
+                &ConfigCommitRequest {
+                    base_revision: 0,
+                    base_digest: empty.digest,
+                    changes: vec![ConfigTreeChange::Create {
+                        path: path(DEFAULT_CONFIG_ENTRYPOINT),
+                        content_type: ConfigContentType::Decodal,
+                        content: "{ answer = 42; }".into(),
+                    }],
+                    entrypoints: vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                    toolchain_fingerprint: "sha256:stale-toolchain".into(),
+                },
+            )
+            .unwrap_err();
+        assert!(matches!(error, Error::WorkspaceConfigConflict(_)));
+        assert!(store.load_workspace_config("w-config").unwrap().is_none());
+    }
+
     #[test]
     fn migration_creates_config_authority_without_changing_applied_migrations() {
         let store = SqliteWorkspaceStore::in_memory().unwrap();

web/workspace/deno.json

@@ -15,6 +15,7 @@
     "@sveltejs/adapter-static": "npm:@sveltejs/adapter-static@3.0.9",
     "@sveltejs/kit": "npm:@sveltejs/kit@2.49.4",
     "@sveltejs/vite-plugin-svelte": "npm:@sveltejs/vite-plugin-svelte@6.2.1",
+    "@codemirror/autocomplete": "npm:@codemirror/autocomplete@6.20.0",
     "@codemirror/state": "npm:@codemirror/state@6.7.1",
     "@codemirror/view": "npm:@codemirror/view@6.43.8",
     "decodal-codemirror": "npm:decodal-codemirror@0.1.6",

web/workspace/deno.lock

@@ -3,6 +3,7 @@
   "specifiers": {
     "jsr:@std/assert@*": "1.0.19",
     "jsr:@std/internal@^1.0.12": "1.0.14",
+    "npm:@codemirror/autocomplete@6.20.0": "6.20.0",
     "npm:@codemirror/state@6.7.1": "6.7.1",
     "npm:@codemirror/view@6.43.8": "6.43.8",
     "npm:@fontsource/ibm-plex-mono@5.3.0": "5.3.0",
@@ -34,9 +35,19 @@
     }
   },
   "npm": {
+    "@codemirror/autocomplete@6.20.0": {
+      "integrity": "sha512-bOwvTOIJcG5FVo5gUUupiwYh8MioPLQ4UcqbcRf7UQ98X90tCa9E1kZ3Z7tqwpZxYyOvh1YTYbmZE9RTfTp5hg==",
+      "dependencies": [
+        "@codemirror/language",
+        "@codemirror/state",
+        "@codemirror/view",
+        "@lezer/common"
+      ]
+    },
     "@codemirror/language@6.12.4": {
       "integrity": "sha512-1q4PaT+o6PbgpkJt4Q8Fv5XJxTy4FUZ4MWETtyiDw3J0Pyr9E2vqcKL+k9wcvjNTIsauxvE7OfmWj3FRPHQ76A==",
       "dependencies": [
+        "@codemirror/state",
         "@codemirror/view",
         "@lezer/common",
         "@lezer/highlight",
@@ -988,6 +999,7 @@
   },
   "workspace": {
     "dependencies": [
+      "npm:@codemirror/autocomplete@6.20.0",
       "npm:@codemirror/state@6.7.1",
       "npm:@codemirror/view@6.43.8",
       "npm:@sveltejs/adapter-static@3.0.9",

web/workspace/src/lib/workspace/config-source/ConfigSourceEditor.svelte

@@ -21,6 +21,10 @@
   let diagnostics = $state<ConfigDiagnostic[]>([]);
   let status = $state("Loading source tree…");
   let busy = $state(false);
+  let draftChanges = $state<ConfigTreeChange[]>([]);
+  let baseRevision = $state(0);
+  let baseDigest = $state("");
+  let renamePath = $state("");
   let toolchain: ConfigSourceToolchain | null = null;
 
   const paths = $derived(
@@ -29,7 +33,7 @@
   const selected = $derived(
     treeState && selectedPath ? treeState.snapshot.entries[selectedPath] : undefined,
   );
-  const dirty = $derived(selected ? source !== selected.content : source.length > 0);
+  const dirty = $derived(draftChanges.length > 0 || (selected ? source !== selected.content : source.length > 0));
 
   onMount(() => {
     toolchain = new ConfigSourceToolchain();
@@ -44,6 +48,11 @@
         selectedPath = Object.keys(treeState.snapshot.entries).toSorted()[0] ?? "";
       }
       source = selectedPath ? treeState.snapshot.entries[selectedPath].content : "";
+      baseRevision = treeState.snapshot.revision;
+      baseDigest = treeState.snapshot.digest;
+      await toolchain?.setSnapshot(treeState.snapshot);
+      draftChanges = [];
+      renamePath = selectedPath;
       diagnostics = [];
       status = treeState.snapshot.revision === 0
         ? "No committed sources yet. Create workspace.dcdl to begin."
@@ -53,9 +62,23 @@
     }
   }
 
-  function select(path: string) {
+  async function stageCurrent() {
+    const change = currentChange();
+    if (!change || !toolchain) return;
+    draftChanges = [...draftChanges.filter((item) => !changeTouches(item, selectedPath)), change];
+    const candidate = await toolchain.applyChanges([change]);
+    if (treeState) treeState = { ...treeState, snapshot: candidate };
+  }
+
+  function changeTouches(change: ConfigTreeChange, path: string): boolean {
+    return change.kind === "rename" ? change.from === path || change.to === path : change.path === path;
+  }
+
+  async function select(path: string) {
+    await stageCurrent();
     selectedPath = path;
     source = treeState?.snapshot.entries[path]?.content ?? "";
+    renamePath = path;
     diagnostics = [];
   }
 
@@ -81,7 +104,9 @@
 
   function entrypoints(): string[] {
     if (!treeState) return [];
-    if (treeState.contract.entrypoints.length > 0) return treeState.contract.entrypoints;
+    const known = new Set(Object.keys(treeState.snapshot.entries));
+    const configured = treeState.contract.entrypoints.filter((path) => known.has(path));
+    if (configured.length > 0) return configured;
     if (treeState.snapshot.entries["workspace.dcdl"] || selectedPath === "workspace.dcdl") {
       return ["workspace.dcdl"];
     }
@@ -90,7 +115,7 @@
 
   async function analyze() {
     if (!toolchain || !treeState || !selectedPath) return;
-    diagnostics = await toolchain.analyze(treeState.snapshot, selectedPath, source);
+    diagnostics = await toolchain.analyze(selectedPath, source);
     status = diagnostics.length === 0 ? "No diagnostics." : `${diagnostics.length} diagnostic(s).`;
   }
 
@@ -106,16 +131,17 @@
 
   async function preview() {
     if (!treeState) return;
-    const change = currentChange();
+    await stageCurrent();
-    if (!change) {
+    if (draftChanges.length === 0) {
       status = "No draft changes to preview.";
       return;
     }
     busy = true;
     try {
       const candidate = await previewConfigTree(workspaceId, {
-        changes: [change],
+        changes: draftChanges,
         entrypoints: entrypoints(),
+        toolchain_fingerprint: treeState.contract.fingerprint,
       });
       diagnostics = [];
       status = `Preview valid · projection ${candidate.evaluation.projection_digest.slice(0, 20)}…`;
@@ -128,19 +154,24 @@
 
   async function commit() {
     if (!treeState) return;
-    const change = currentChange();
+    await stageCurrent();
-    if (!change) {
+    if (draftChanges.length === 0) {
       status = "No draft changes to commit.";
       return;
     }
     busy = true;
     try {
       treeState = await commitConfigTree(workspaceId, {
-        base_revision: treeState.snapshot.revision,
+        base_revision: baseRevision,
-        base_digest: treeState.snapshot.digest,
+        base_digest: baseDigest,
-        changes: [change],
+        changes: draftChanges,
         entrypoints: entrypoints(),
+        toolchain_fingerprint: treeState.contract.fingerprint,
       });
+      draftChanges = [];
+      baseRevision = treeState.snapshot.revision;
+      baseDigest = treeState.snapshot.digest;
+      await toolchain?.setSnapshot(treeState.snapshot);
       source = treeState.snapshot.entries[selectedPath]?.content ?? "";
       diagnostics = [];
       status = `Committed revision ${treeState.snapshot.revision}.`;
@@ -161,29 +192,38 @@
   }
 
   async function deleteEntry() {
-    if (!treeState || !selected) return;
+    if (!treeState || !selected || !toolchain) return;
-    busy = true;
+    const change: ConfigTreeChange = {
-    try {
-      const remainingEntrypoints = treeState.contract.entrypoints.filter((path) => path !== selectedPath);
-      treeState = await commitConfigTree(workspaceId, {
-        base_revision: treeState.snapshot.revision,
-        base_digest: treeState.snapshot.digest,
-        changes: [{
       kind: "delete",
       path: selectedPath,
       expected_digest: selected.content_digest,
-        }],
+    };
-        entrypoints: remainingEntrypoints,
+    draftChanges = [...draftChanges.filter((item) => !changeTouches(item, selectedPath)), change];
-      });
+    const candidate = await toolchain.applyChanges([change]);
-      selectedPath = Object.keys(treeState.snapshot.entries).toSorted()[0] ?? "";
+    treeState = { ...treeState, snapshot: candidate };
-      source = selectedPath ? treeState.snapshot.entries[selectedPath].content : "";
+    selectedPath = Object.keys(candidate.entries).toSorted()[0] ?? "";
-      diagnostics = [];
+    source = selectedPath ? candidate.entries[selectedPath].content : "";
-      status = `Committed revision ${treeState.snapshot.revision}.`;
+    renamePath = selectedPath;
-    } catch (error) {
+    status = "Delete staged. Preview and Commit to persist the candidate tree.";
-      status = String(error);
-    } finally {
-      busy = false;
   }
+
+  async function renameEntry() {
+    if (!treeState || !selected || !toolchain) return;
+    const to = renamePath.trim();
+    if (!to || to === selectedPath) return;
+    await stageCurrent();
+    const change: ConfigTreeChange = {
+      kind: "rename",
+      from: selectedPath,
+      to,
+      expected_digest: selected.content_digest,
+    };
+    draftChanges = [...draftChanges.filter((item) => !changeTouches(item, selectedPath)), change];
+    const candidate = await toolchain.applyChanges([change]);
+    treeState = { ...treeState, snapshot: candidate };
+    selectedPath = to;
+    source = candidate.entries[to]?.content ?? "";
+    status = `Rename to ${to} staged. Preview and Commit to persist.`;
   }
 </script>
 
@@ -216,6 +256,8 @@
         <strong>{selectedPath || "Select or create a source"}</strong>
       </div>
       <div class="config-source-actions">
+        <input aria-label="Rename path" bind:value={renamePath} disabled={!selected || busy} />
+        <button type="button" onclick={renameEntry} disabled={!selected || renamePath === selectedPath || busy}>Rename</button>
         <button type="button" onclick={format} disabled={!selectedPath || busy}>Format</button>
         <button type="button" onclick={analyze} disabled={!selectedPath || busy}>Analyze</button>
         <button type="button" onclick={preview} disabled={!dirty || busy}>Preview</button>
@@ -223,7 +265,12 @@
         <button class="danger" type="button" onclick={deleteEntry} disabled={!selected || busy}>Delete</button>
       </div>
     </header>
-    <DecodalSourceEditor value={source} readonly={!selectedPath || busy} onChange={(value) => source = value} />
+    <DecodalSourceEditor
+      value={source}
+      readonly={!selectedPath || busy}
+      onChange={(value) => source = value}
+      onComplete={(value, offset, explicit) => toolchain?.complete(selectedPath, value, offset, explicit) ?? Promise.resolve(null)}
+    />
     <p class="config-source-status" aria-live="polite">{status}</p>
     {#if diagnostics.length > 0}
       <ol class="config-source-diagnostics">

web/workspace/src/lib/workspace/config-source/generated/config_source_wasm.d.ts

@@ -3,19 +3,31 @@
 
 export function analyze_snapshot(snapshot: any, entrypoint: string, source_override?: string | null): any;
 
+export function apply_changes(changes: any): any;
+
+export function complete_current(entrypoint: string, source: string, utf8_byte_offset: number, explicit: boolean): any;
+
+export function evaluate_current(contract: any): any;
+
 export function evaluate_snapshot(snapshot: any, contract: any): any;
 
 export function formatSource(source: string): string;
 
 export function format_source(source: string): string;
 
+export function set_snapshot(snapshot: any): void;
+
 export type InitInput = RequestInfo | URL | Response | BufferSource | WebAssembly.Module;
 
 export interface InitOutput {
     readonly memory: WebAssembly.Memory;
     readonly analyze_snapshot: (a: any, b: number, c: number, d: number, e: number) => [number, number, number];
+    readonly apply_changes: (a: any) => [number, number, number];
+    readonly complete_current: (a: number, b: number, c: number, d: number, e: number, f: number) => [number, number, number];
+    readonly evaluate_current: (a: any) => [number, number, number];
     readonly evaluate_snapshot: (a: any, b: any) => [number, number, number];
     readonly format_source: (a: number, b: number) => [number, number, number, number];
+    readonly set_snapshot: (a: any) => [number, number];
     readonly formatSource: (a: number, b: number) => [number, number];
     readonly __wbindgen_malloc: (a: number, b: number) => number;
     readonly __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;

web/workspace/src/lib/workspace/config-source/generated/config_source_wasm.js

@@ -18,6 +18,49 @@ export function analyze_snapshot(snapshot, entrypoint, source_override) {
     return takeFromExternrefTable0(ret[0]);
 }
 
+/**
+ * @param {any} changes
+ * @returns {any}
+ */
+export function apply_changes(changes) {
+    const ret = wasm.apply_changes(changes);
+    if (ret[2]) {
+        throw takeFromExternrefTable0(ret[1]);
+    }
+    return takeFromExternrefTable0(ret[0]);
+}
+
+/**
+ * @param {string} entrypoint
+ * @param {string} source
+ * @param {number} utf8_byte_offset
+ * @param {boolean} explicit
+ * @returns {any}
+ */
+export function complete_current(entrypoint, source, utf8_byte_offset, explicit) {
+    const ptr0 = passStringToWasm0(entrypoint, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+    const len0 = WASM_VECTOR_LEN;
+    const ptr1 = passStringToWasm0(source, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+    const len1 = WASM_VECTOR_LEN;
+    const ret = wasm.complete_current(ptr0, len0, ptr1, len1, utf8_byte_offset, explicit);
+    if (ret[2]) {
+        throw takeFromExternrefTable0(ret[1]);
+    }
+    return takeFromExternrefTable0(ret[0]);
+}
+
+/**
+ * @param {any} contract
+ * @returns {any}
+ */
+export function evaluate_current(contract) {
+    const ret = wasm.evaluate_current(contract);
+    if (ret[2]) {
+        throw takeFromExternrefTable0(ret[1]);
+    }
+    return takeFromExternrefTable0(ret[0]);
+}
+
 /**
  * @param {any} snapshot
  * @param {any} contract
@@ -75,6 +118,16 @@ export function format_source(source) {
     }
 }
 
+/**
+ * @param {any} snapshot
+ */
+export function set_snapshot(snapshot) {
+    const ret = wasm.set_snapshot(snapshot);
+    if (ret[1]) {
+        throw takeFromExternrefTable0(ret[0]);
+    }
+}
+
 function __wbg_get_imports() {
     const import0 = {
         __proto__: null,
@@ -199,6 +252,16 @@ function __wbg_get_imports() {
             const ret = result;
             return ret;
         },
+        __wbg_instanceof_Map_a10a2795ef4bfe97: function(arg0) {
+            let result;
+            try {
+                result = arg0 instanceof Map;
+            } catch (_) {
+                result = false;
+            }
+            const ret = result;
+            return ret;
+        },
         __wbg_instanceof_Uint8Array_4b8da683deb25d72: function(arg0) {
             let result;
             try {

web/workspace/src/lib/workspace/config-source/generated/config_source_wasm_bg.wasm.d.ts

@@ -2,8 +2,12 @@
 /* eslint-disable */
 export const memory: WebAssembly.Memory;
 export const analyze_snapshot: (a: any, b: number, c: number, d: number, e: number) => [number, number, number];
+export const apply_changes: (a: any) => [number, number, number];
+export const complete_current: (a: number, b: number, c: number, d: number, e: number, f: number) => [number, number, number];
+export const evaluate_current: (a: any) => [number, number, number];
 export const evaluate_snapshot: (a: any, b: any) => [number, number, number];
 export const format_source: (a: number, b: number) => [number, number, number, number];
+export const set_snapshot: (a: any) => [number, number];
 export const formatSource: (a: number, b: number) => [number, number];
 export const __wbindgen_malloc: (a: number, b: number) => number;
 export const __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;

web/workspace/src/lib/workspace/config-source/toolchain.ts

@@ -1,75 +1,57 @@
-import type {
+import type { ConfigDiagnostic, ConfigTreeChange, ConfigTreeSnapshot, ToolchainContract } from "./types.ts";
-  ConfigDiagnostic,
+import type { ConfigSourceWorkerRequest, ConfigSourceWorkerResponse } from "./toolchain.worker.ts";
-  ConfigTreeSnapshot,
-  ToolchainContract,
-} from "./types.ts";
-import type {
-  ConfigSourceWorkerRequest,
-  ConfigSourceWorkerResponse,
-} from "./toolchain.worker.ts";
 
-type ConfigSourceWorkerCommand =
+type Command =
+  | Omit<Extract<ConfigSourceWorkerRequest, { kind: "set_snapshot" }>, "id">
+  | Omit<Extract<ConfigSourceWorkerRequest, { kind: "apply_changes" }>, "id">
   | Omit<Extract<ConfigSourceWorkerRequest, { kind: "analyze" }>, "id">
   | Omit<Extract<ConfigSourceWorkerRequest, { kind: "evaluate" }>, "id">
+  | Omit<Extract<ConfigSourceWorkerRequest, { kind: "complete" }>, "id">
   | Omit<Extract<ConfigSourceWorkerRequest, { kind: "format" }>, "id">;
 
 export class ConfigSourceToolchain {
   #worker: Worker;
   #nextId = 1;
-  #pending = new Map<
+  #pending = new Map<number, { resolve: (value: unknown) => void; reject: (reason: unknown) => void }>();
-    number,
-    { resolve: (value: unknown) => void; reject: (reason: unknown) => void }
-  >();
 
-  constructor(
+  constructor(worker = new Worker(new URL("./toolchain.worker.ts", import.meta.url), { type: "module" })) {
-    worker = new Worker(new URL("./toolchain.worker.ts", import.meta.url), {
-      type: "module",
-    }),
-  ) {
     this.#worker = worker;
-    worker.addEventListener(
+    worker.addEventListener("message", (event: MessageEvent<ConfigSourceWorkerResponse>) => {
-      "message",
-      (event: MessageEvent<ConfigSourceWorkerResponse>) => {
       const pending = this.#pending.get(event.data.id);
       if (!pending) return;
       this.#pending.delete(event.data.id);
       if (event.data.ok) pending.resolve(event.data.result);
       else pending.reject(event.data.error);
-      },
+    });
-    );
   }
 
-  analyze(
+  setSnapshot(snapshot: ConfigTreeSnapshot): Promise<void> {
-    snapshot: ConfigTreeSnapshot,
+    return this.#request({ kind: "set_snapshot", snapshot });
-    path: string,
-    source?: string,
-  ): Promise<ConfigDiagnostic[]> {
-    return this.#request({ kind: "analyze", snapshot, path, source });
   }
-
+  applyChanges(changes: ConfigTreeChange[]): Promise<ConfigTreeSnapshot> {
-  evaluate(snapshot: ConfigTreeSnapshot, contract: ToolchainContract) {
+    return this.#request({ kind: "apply_changes", changes });
-    return this.#request({ kind: "evaluate", snapshot, contract });
+  }
+  analyze(path: string, source?: string): Promise<ConfigDiagnostic[]> {
+    return this.#request({ kind: "analyze", path, source });
+  }
+  evaluate(contract: ToolchainContract) {
+    return this.#request({ kind: "evaluate", contract });
+  }
+  complete(path: string, source: string, utf8ByteOffset: number, explicit = false): Promise<import("@codemirror/autocomplete").CompletionResult | null> {
+    return this.#request({ kind: "complete", path, source, utf8ByteOffset, explicit });
   }
-
   format(source: string): Promise<string> {
     return this.#request({ kind: "format", source });
   }
-
   close(): void {
     this.#worker.terminate();
-    for (const pending of this.#pending.values()) {
+    for (const pending of this.#pending.values()) pending.reject(new Error("config source toolchain was closed"));
-      pending.reject(new Error("config source toolchain was closed"));
-    }
     this.#pending.clear();
   }
-
+  #request<T>(request: Command): Promise<T> {
-  #request<T>(request: ConfigSourceWorkerCommand): Promise<T> {
     const id = this.#nextId++;
     return new Promise<T>((resolve, reject) => {
-      this.#pending.set(id, {
+      this.#pending.set(id, { resolve: (value) => resolve(value as T), reject });
-        resolve: (value) => resolve(value as T),
-        reject,
-      });
       this.#worker.postMessage({ ...request, id });
     });
   }

web/workspace/src/lib/workspace/config-source/toolchain.worker.ts

@@ -1,28 +1,19 @@
 import init, {
   analyze_snapshot,
-  evaluate_snapshot,
+  apply_changes,
+  complete_current,
+  evaluate_current,
   format_source,
+  set_snapshot,
 } from "./generated/config_source_wasm.js";
-import type {
+import type { ConfigTreeChange } from "./types.ts";
-  ConfigDiagnostic,
-  ConfigTreeSnapshot,
-  ToolchainContract,
-} from "./types.ts";
 
 export type ConfigSourceWorkerRequest =
-  | {
+  | { id: number; kind: "set_snapshot"; snapshot: unknown }
-    id: number;
+  | { id: number; kind: "apply_changes"; changes: ConfigTreeChange[] }
-    kind: "analyze";
+  | { id: number; kind: "analyze"; path: string; source?: string }
-    snapshot: ConfigTreeSnapshot;
+  | { id: number; kind: "evaluate"; contract: unknown }
-    path: string;
+  | { id: number; kind: "complete"; path: string; source: string; utf8ByteOffset: number; explicit: boolean }
-    source?: string;
-  }
-  | {
-    id: number;
-    kind: "evaluate";
-    snapshot: ConfigTreeSnapshot;
-    contract: ToolchainContract;
-  }
   | { id: number; kind: "format"; source: string };
 
 export type ConfigSourceWorkerResponse =
@@ -30,24 +21,32 @@ export type ConfigSourceWorkerResponse =
   | { id: number; ok: false; error: unknown };
 
 const ready = init();
+let snapshot: unknown = null;
 
-self.onmessage = async (
+self.onmessage = async (event: MessageEvent<ConfigSourceWorkerRequest>): Promise<void> => {
-  event: MessageEvent<ConfigSourceWorkerRequest>,
-): Promise<void> => {
   const request = event.data;
   try {
     await ready;
     let result: unknown;
     switch (request.kind) {
+      case "set_snapshot":
+        snapshot = request.snapshot;
+        set_snapshot(request.snapshot);
+        result = null;
+        break;
+      case "apply_changes":
+        snapshot = apply_changes(request.changes);
+        result = snapshot;
+        break;
       case "analyze":
-        result = analyze_snapshot(
+        if (!snapshot) throw new Error("config source snapshot is not initialized");
-          request.snapshot,
+        result = analyze_snapshot(snapshot, request.path, request.source);
-          request.path,
-          request.source,
-        ) as ConfigDiagnostic[];
         break;
       case "evaluate":
-        result = evaluate_snapshot(request.snapshot, request.contract);
+        result = evaluate_current(request.contract);
+        break;
+      case "complete":
+        result = complete_current(request.path, request.source, request.utf8ByteOffset, request.explicit);
         break;
       case "format":
         result = format_source(request.source);
@@ -55,15 +54,6 @@ self.onmessage = async (
     }
     self.postMessage({ id: request.id, ok: true, result });
   } catch (error) {
-    self.postMessage({
+    self.postMessage({ id: request.id, ok: false, error: error instanceof Error ? error.message : error });
-      id: request.id,
-      ok: false,
-      error: normalizeError(error),
-    });
   }
 };
-
-function normalizeError(error: unknown): unknown {
-  if (error instanceof Error) return error.message;
-  return error;
-}

web/workspace/src/lib/workspace/config-source/types.ts

@@ -89,4 +89,5 @@ export interface ConfigCommitRequest {
   base_digest: string;
   changes: ConfigTreeChange[];
   entrypoints: VirtualPath[];
+  toolchain_fingerprint: string;
 }

web/workspace/src/lib/workspace/settings/DecodalSourceEditor.svelte

@@ -1,5 +1,6 @@
 <script lang="ts">
   import { untrack } from 'svelte';
+  import { autocompletion, type CompletionContext, type CompletionResult } from '@codemirror/autocomplete';
   import { EditorState } from '@codemirror/state';
   import { EditorView, keymap, lineNumbers, highlightActiveLine, drawSelection } from '@codemirror/view';
   import { decodal } from 'decodal-codemirror';
@@ -9,11 +10,13 @@
     readonly = false,
     ariaLabel = 'Decodal source',
     onChange = (_value: string) => {},
+    onComplete = undefined,
   }: {
     value?: string;
     readonly?: boolean;
     ariaLabel?: string;
     onChange?: (value: string) => void;
+    onComplete?: (source: string, utf8ByteOffset: number, explicit: boolean) => Promise<CompletionResult | null>;
   } = $props();
 
   let host = $state<HTMLDivElement | null>(null);
@@ -39,6 +42,7 @@
     const initialValue = untrack(() => value);
     const initialReadonly = untrack(() => readonly);
     const handleChange = untrack(() => onChange);
+    const handleComplete = untrack(() => onComplete);
     const editor = new EditorView({
       parent: host,
       state: EditorState.create({
@@ -48,6 +52,11 @@
           drawSelection(),
           highlightActiveLine(),
           decodal(),
+          ...(handleComplete ? [autocompletion({ override: [async (context: CompletionContext) => {
+            const doc = context.state.doc.toString();
+            const utf8ByteOffset = new TextEncoder().encode(doc.slice(0, context.pos)).byteLength;
+            return await handleComplete(doc, utf8ByteOffset, context.explicit);
+          }] })] : []),
           keymap.of([]),
           EditorState.readOnly.of(initialReadonly),
           EditorView.editable.of(!initialReadonly),

web/workspace/src/lib/workspace/styles/settings.css

@@ -572,7 +572,8 @@
     color: var(--text-muted);
     font-size: 0.75rem;
   }
-  .config-source-create input {
+  .config-source-create input,
+  .config-source-actions input {
     min-width: 0;
     border: 1px solid var(--line);
     border-radius: 0.45rem;

web/workspace/test/config-source/api.test.ts

@@ -24,12 +24,13 @@ Deno.test("config source API stays workspace-scoped and separates preview from c
 
   await fetchConfigTree("w/one", fetcher);
   await fetchConfigEntry("w/one", "profiles/main.dcdl", fetcher);
-  await previewConfigTree("w/one", { changes: [], entrypoints: [] }, fetcher);
+  await previewConfigTree("w/one", { changes: [], entrypoints: [], toolchain_fingerprint: "sha256:toolchain" }, fetcher);
   await commitConfigTree("w/one", {
     base_revision: 4,
     base_digest: "sha256:base",
     changes: [],
     entrypoints: [],
+    toolchain_fingerprint: "sha256:toolchain",
   }, fetcher);
 
   assertEquals(calls.map((call) => call.url), [
@@ -52,7 +53,7 @@ Deno.test("config source API surfaces failed evaluation instead of treating it a
     )) as typeof fetch;
   let message = "";
   try {
-    await previewConfigTree("w", { changes: [], entrypoints: [] }, fetcher);
+    await previewConfigTree("w", { changes: [], entrypoints: [], toolchain_fingerprint: "sha256:toolchain" }, fetcher);
   } catch (error) {
     message = String(error);
   }