') + ')', 'gi'); if (regex.test(text)) { found = true; var frag = document.createDocumentFragment(); var parts = text.split(regex); parts.forEach(function(part, i) { if (i % 2 === 0) { frag.appendChild(document.createTextNode(part)); } else { var span = document.createElement('span'); span.className = 'userscript-highlight'; span.textContent = part; frag.appendChild(span); } }); node.parentNode.replaceChild(frag, node); } }); } else if (node.nodeType === 1 && node.childNodes) { // element var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT']; if (!skipTags.includes(node.tagName)) { Array.from(node.childNodes).forEach(highlight); } } } highlight(document.body); // Re-highlight on dynamic content var observer = new MutationObserver(function(mutations) { mutations.forEach(function(m) { m.addedNodes.forEach(function(node) { if (node.nodeType === 1 || node.nodeType === 3) highlight(node); }); }); }); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + ', 'i'); if (__m === '*' || __re.test(location.href)) { // Strip utm_, fbclid, gclid, etc. from all links on page (function() { var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content', 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid', 'ref', 'ref_src', 'source', 'medium', 'campaign']; function cleanUrl(url) { try { var u = new URL(url, window.location.origin); var changed = false; trackingParams.forEach(function(p) { if (u.searchParams.has(p)) { u.searchParams.delete(p); changed = true; } }); return changed ? u.toString() : url; } catch (e) { return url; } } function cleanLinks() { document.querySelectorAll('a[href]').forEach(function(a) { var clean = cleanUrl(a.href); if (clean !== a.href) a.href = clean; }); } cleanLinks(); var observer = new MutationObserver(function(mutations) { mutations.forEach(function(m) { m.addedNodes.forEach(function(node) { if (node.nodeType === 1) { if (node.tagName === 'A') cleanLinks(); node.querySelectorAll('a[href]').forEach(function(a) { var clean = cleanUrl(a.href); if (clean !== a.href) a.href = clean; }); } }); }); }); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); } })(); (function(){ try { var __m = "youtube.com"; var __re = new RegExp('^' + "youtube\\.com" + ', 'i'); if (__m === '*' || __re.test(location.href)) { // Auto-enable theater mode on YouTube (function() { function tryTheater() { var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]'); if (btn && !btn.classList.contains('activated')) { btn.click(); } } // Try immediately tryTheater(); // Try after navigation (SPA) var lastUrl = location.href; setInterval(function() { if (location.href !== lastUrl) { lastUrl = location.href; setTimeout(tryTheater, 500); } }, 1000); // Also try on player load var observer = new MutationObserver(tryTheater); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + ', 'i'); if (__m === '*' || __re.test(location.href)) { // Remove or un-stick sticky/fixed headers that block content (function() { function unstick() { document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) { if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') { el.style.position = 'static'; el.style.top = 'auto'; el.style.zIndex = 'auto'; } }); } unstick(); var observer = new MutationObserver(unstick); observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] }); })(); } } catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); } })(); })(); fix: call onerror for nested catch blocks in handlePostRequest by kdn-posipaka · Pull Request #1677 · modelcontextprotocol/typescript-sdk · GitHub
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fix: call onerror for nested catch blocks in handlePostRequest - #1677

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kdn-posipaka wants to merge 2 commits into
modelcontextprotocol:mainfrom
kdn-posipaka:fix/transport-onerror-1395
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fix: call onerror for nested catch blocks in handlePostRequest#1677
kdn-posipaka wants to merge 2 commits into
modelcontextprotocol:mainfrom
kdn-posipaka:fix/transport-onerror-1395

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@kdn-posipaka

@kdn-posipakakdn-posipaka commented Mar 13, 2026

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Summary

Fixes#1395

In handlePostRequest, two nested try/catch blocks were silently swallowing errors:

  1. JSON parsing (req.json()) — returned createJsonErrorResponse(400, -32_700, 'Parse error: Invalid JSON') without calling this.onerror
  2. JSON-RPC schema validation (JSONRPCMessageSchema.parse) — returned createJsonErrorResponse(400, -32_700, 'Parse error: Invalid JSON-RPC message') without calling this.onerror

The outer catch at the end of handlePostRequest correctly calls this.onerror?.(error as Error), but these nested catches did not, making it impossible for consumers to observe these error conditions.

Changes

  • Added this.onerror?.(error as Error) to both nested catch blocks, consistent with the pattern used in the outer catch and in other methods (e.g., replayEvents, validateRequestHeaders)
  • Added 2 tests verifying onerror is called for invalid JSON and invalid JSON-RPC messages

Testing

All existing tests pass plus 2 new tests (39 total in server package).

kai-agent-free
fix: call onerror for nested catch blocks in handlePostRequest
d66d76e
In handlePostRequest, two nested try/catch blocks (JSON parsing and
JSON-RPC schema validation) were creating error responses via
createJsonErrorResponse but not calling this.onerror, silently
swallowing the errors. The outer catch correctly called this.onerror.
Add this.onerror?.(error as Error) calls to both nested catches,
consistent with the pattern used elsewhere in the codebase.
Add tests verifying onerror is called for both error cases.
Fixesmodelcontextprotocol#1395
@changeset-bot

changeset-botBot commented Mar 13, 2026•
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🦋 Changeset detected

Latest commit: 49d2573

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 4 packages
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@modelcontextprotocol/serverPatch
@modelcontextprotocol/expressPatch
@modelcontextprotocol/honoPatch
@modelcontextprotocol/nodePatch

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commit: 1debab0

@felixweinberger

felixweinberger commented Mar 25, 2026

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Thanks for the contribution! Closing in favor of #1433.

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Successfully merging this pull request may close these issues.

Some transport errors are silently swallowed due to missing onerror callback usage

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@kdn-posipaka@felixweinberger