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fix completions not displayed for field access #970

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Merged
merged 1 commit into from
Nov 20, 2025
Merged

fix completions not displayed for field access #970

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18 changes: 10 additions & 8 deletions ...-panel/src/components/editors/MultiModeExpressionEditor/ChipExpressionEditor/CodeUtils.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -397,22 +397,24 @@ export const buildOnChangeListner = (onTrigeer: (newValue: string, cursor: Curso
return onChangeListner;
}

export const buildCompletionSource = (getCompletions: () => CompletionItem[]) => {
return (context: CompletionContext): CompletionResult | null => {
export const buildCompletionSource = (getCompletions: () => Promise<CompletionItem[]>) => {
return async (context: CompletionContext): Promise<CompletionResult | null> => {
const textBeforeCursor = context.state.doc.toString().slice(0, context.pos);
const lastNonSpaceChar = textBeforeCursor.trimEnd().slice(-1);

const word = context.matchBefore(/\w*/);
if (!word || (word.from === word.to && !context.explicit)) {
if (lastNonSpaceChar !== '.' && (
!word || (word.from === word.to && !context.explicit)
)) {
return null;
}

const textBeforeCursor = context.state.doc.toString().slice(0, context.pos);
const lastNonSpaceChar = textBeforeCursor.trimEnd().slice(-1);

// Don't show completions for trigger characters
if (lastNonSpaceChar === '+' || lastNonSpaceChar === ':') {
if (lastNonSpaceChar === '+') {
return null;
}

const completions = getCompletions();
const completions = await getCompletions();
const prefix = word.text;
const filteredCompletions = filterCompletionsByPrefixAndType(completions, prefix);

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24 changes: 21 additions & 3 deletions ...ditors/MultiModeExpressionEditor/ChipExpressionEditor/components/ChipExpressionEditor.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@

import { EditorState } from "@codemirror/state";
import { EditorView, keymap, tooltips } from "@codemirror/view";
import React, { useEffect, useRef, useState } from "react";
import React, { useEffect, useMemo, useRef, useState } from "react";
import { useFormContext } from "../../../../../context";
import {
buildNeedTokenRefetchListner,
Expand Down Expand Up @@ -88,8 +88,9 @@ export const ChipExpressionEditorComponent = (props: ChipExpressionEditorCompone
const fieldContainerRef = useRef<HTMLDivElement>(null);
const viewRef = useRef<EditorView | null>(null);
const [isTokenUpdateScheduled, setIsTokenUpdateScheduled] = useState(true);
const completionsRef = useRef(props.completions);
const completionsRef = useRef<CompletionItem[]>(props.completions);
const helperPaneToggleButtonRef = useRef<HTMLButtonElement>(null);
const completionsFetchScheduledRef = useRef<boolean>(false);

Comment on lines +91 to 94
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@coderabbitai coderabbitai bot Nov 19, 2025

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⚠️ Potential issue | 🟠 Major

Avoid unbounded requestAnimationFrame polling when completions don’t arrive

The handshake between completionsFetchScheduledRef and waitForStateChange is generally good, but there’s a failure mode:

  • On every doc change, handleChangeListner sets completionsFetchScheduledRef.current = true.
  • waitForStateChange then recursively polls via requestAnimationFrame until completionsFetchScheduledRef.current becomes false.
  • It is set back to false only in the useEffect that mirrors props.completions into completionsRef (line 303–305).

If, for any reason, props.completions isn’t updated (backend error, RPC being disabled, or a parent component choosing not to update on certain edits), completionsFetchScheduledRef.current will stay true and:

  • waitForStateChange’s Promise will never resolve, leaving CodeMirror’s completion request hanging.
  • requestAnimationFrame(checkState) will run indefinitely every frame, which is a subtle performance leak.

Consider adding a timeout/fallback and ensuring the scheduled flag is always cleared, even on failure:

-    const waitForStateChange = (): Promise<CompletionItem[]> => {
-        return new Promise((resolve) => {
-            const checkState = () => {
-                if (!completionsFetchScheduledRef.current) {
-                    resolve(completionsRef.current);
-                } else {
-                    requestAnimationFrame(checkState);
-                }
-            };
-            checkState();
-        });
-    };
+    const waitForStateChange = (timeoutMs = 500): Promise<CompletionItem[]> => {
+        const start = performance.now();
+        return new Promise((resolve) => {
+            const checkState = () => {
+                const timedOut = performance.now() - start > timeoutMs;
+                if (!completionsFetchScheduledRef.current || timedOut) {
+                    // On timeout, fall back to whatever completions we currently have.
+                    completionsFetchScheduledRef.current = false;
+                    resolve(completionsRef.current);
+                    return;
+                }
+                requestAnimationFrame(checkState);
+            };
+            checkState();
+        });
+    };

Additionally, make sure any completion-fetching code that can fail still drives props.completions (or explicitly flips completionsFetchScheduledRef.current back to false in its error path) so the editor doesn’t get stuck waiting.

Also applies to: 102-115, 129-145, 300-305

🤖 Prompt for AI Agents 
In
workspaces/ballerina/ballerina-side-panel/src/components/editors/MultiModeExpressionEditor/ChipExpressionEditor/components/ChipExpressionEditor.tsx
around lines 91-94 (and similarly 102-115, 129-145, 300-305), the
requestAnimationFrame polling driven by completionsFetchScheduledRef can spin
forever if props.completions never updates; add a bounded timeout/fallback
inside waitForStateChange so the Promise resolves after a configurable max wait
(e.g., 500-1000ms) and ensure completionsFetchScheduledRef.current is cleared on
timeout or any error path; also update any completion-fetching error handlers to
flip completionsFetchScheduledRef.current = false so the editor never remains
stuck waiting.

const { expressionEditor } = useFormContext();
const expressionEditorRpcManager = expressionEditor?.rpcManager;
Expand All @@ -99,6 +100,7 @@ export const ChipExpressionEditorComponent = (props: ChipExpressionEditorCompone
});

const handleChangeListner = buildOnChangeListner((newValue, cursor) => {
completionsFetchScheduledRef.current = true;
props.onChange(newValue, cursor.position.to);
const textBeforeCursor = newValue.slice(0, cursor.position.to);
const lastNonSpaceChar = textBeforeCursor.trimEnd().slice(-1);
Expand All @@ -124,7 +126,22 @@ export const ChipExpressionEditorComponent = (props: ChipExpressionEditorCompone
setIsTokenUpdateScheduled(true);
});

const completionSource = buildCompletionSource(() => completionsRef.current);
const waitForStateChange = (): Promise<CompletionItem[]> => {
return new Promise((resolve) => {
const checkState = () => {
if (!completionsFetchScheduledRef.current) {
resolve(completionsRef.current);
} else {
requestAnimationFrame(checkState);
}
};
checkState();
});
};

const completionSource = useMemo(() => {
return buildCompletionSource(waitForStateChange);
}, [props.completions]);

const helperPaneKeymap = buildHelperPaneKeymap(() => helperPaneState.isOpen, () => {
setHelperPaneState(prev => ({ ...prev, isOpen: false }));
Expand Down Expand Up @@ -284,6 +301,7 @@ export const ChipExpressionEditorComponent = (props: ChipExpressionEditorCompone
// just don't touch this.
useEffect(() => {
completionsRef.current = props.completions;
completionsFetchScheduledRef.current = false;
}, [props.completions]);

useEffect(() => {
Expand Down
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