mcp: drain SSE messages when closing - #1192

Open
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom
jstar0:fix/1191-sse-close-drain
Open

mcp: drain SSE messages when closing#1192
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom
jstar0:fix/1191-sse-close-drain

Conversation

@jstar0

@jstar0jstar0 commented Aug 23, 2026

Copy link
Copy Markdown
Contributor

Fixes#1191.

SSEServerTransport.Close previously closed the session signal without draining buffered client messages. Because Read and ServeHTTP select between the message queue and the closed signal, a closed session could deliver stale messages or acknowledge a POST with 202 Accepted even though the message would never be processed.

This change:

  • Drains buffered incoming messages when the server connection closes.
  • Checks the closed state before and after queue operations so close races return io.EOF or 400 session closed.
  • Adds regression tests for stale post-close reads and POST responses after close.

Tests:

  • go test ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server|Handler_DiscoverFallsBackToInitialize|ClientTransport_HTTPErrors|405AllowHeader)$' -count=20
  • go test -race ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server)$' -count=20
  • go vet ./...
  • go test ./... (the MCP package still has the pre-existing localhost protection failure where the 0.0.0.0 via localhost rejects evil.com case receives HTTP 200 instead of 403; all other packages pass)

@jstar0@openhands-agent
mcp: drain SSE messages when closing
44aeebb
Co-authored-by: openhands <openhands@all-hands.dev>
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

No reviews

Assignees

No one assigned

Labels

None yet

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

sse: Close does not drain incoming; Read can deliver stale messages after Close and POST can return false 202

1 participant

@jstar0
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
mcp: drain SSE messages when closing - #1192
Open
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Open
mcp: drain SSE messages when closing#1192
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Conversation
@jstar0
@jstar0jstar0
commented
Aug 23, 2026

Copy link


Copy Markdown

Contributor
Fixes#1191.
SSEServerTransport.Close previously closed the session signal without draining buffered client messages. Because Read and ServeHTTP select between the message queue and the closed signal, a closed session could deliver stale messages or acknowledge a POST with 202 Accepted even though the message would never be processed.
This change:
  • Drains buffered incoming messages when the server connection closes.
  • Checks the closed state before and after queue operations so close races return io.EOF or 400 session closed.
  • Adds regression tests for stale post-close reads and POST responses after close.
Tests:
  • go test ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server|Handler_DiscoverFallsBackToInitialize|ClientTransport_HTTPErrors|405AllowHeader)$' -count=20
  • go test -race ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server)$' -count=20
  • go vet ./...
  • go test ./... (the MCP package still has the pre-existing localhost protection failure where the 0.0.0.0 via localhost rejects evil.com case receives HTTP 200 instead of 403; all other packages pass)
@jstar0@openhands-agent
mcp: drain SSE messages when closing
44aeebb
Co-authored-by: openhands <openhands@all-hands.dev>
Sign up for freeto join this conversation on GitHub.
Already have an account?
Sign in to comment

Reviewers


No reviews


Assignees


No one assigned


Labels


None yet


Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

sse: Close does not drain incoming; Read can deliver stale messages after Close and POST can return false 202


1 participant

@jstar0

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
mcp: drain SSE messages when closing - #1192
Open
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Open
mcp: drain SSE messages when closing#1192
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Conversation
@jstar0
@jstar0jstar0
commented
Aug 23, 2026

Copy link


Copy Markdown

Contributor
Fixes#1191.
SSEServerTransport.Close previously closed the session signal without draining buffered client messages. Because Read and ServeHTTP select between the message queue and the closed signal, a closed session could deliver stale messages or acknowledge a POST with 202 Accepted even though the message would never be processed.
This change:
  • Drains buffered incoming messages when the server connection closes.
  • Checks the closed state before and after queue operations so close races return io.EOF or 400 session closed.
  • Adds regression tests for stale post-close reads and POST responses after close.
Tests:
  • go test ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server|Handler_DiscoverFallsBackToInitialize|ClientTransport_HTTPErrors|405AllowHeader)$' -count=20
  • go test -race ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server)$' -count=20
  • go vet ./...
  • go test ./... (the MCP package still has the pre-existing localhost protection failure where the 0.0.0.0 via localhost rejects evil.com case receives HTTP 200 instead of 403; all other packages pass)
@jstar0@openhands-agent
mcp: drain SSE messages when closing
44aeebb
Co-authored-by: openhands <openhands@all-hands.dev>
Sign up for freeto join this conversation on GitHub.
Already have an account?
Sign in to comment

Reviewers


No reviews


Assignees


No one assigned


Labels


None yet


Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

sse: Close does not drain incoming; Read can deliver stale messages after Close and POST can return false 202


1 participant

@jstar0

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
mcp: drain SSE messages when closing - #1192
Open
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Open
mcp: drain SSE messages when closing#1192
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Conversation
@jstar0
@jstar0jstar0
commented
Aug 23, 2026

Copy link


Copy Markdown

Contributor
Fixes#1191.
SSEServerTransport.Close previously closed the session signal without draining buffered client messages. Because Read and ServeHTTP select between the message queue and the closed signal, a closed session could deliver stale messages or acknowledge a POST with 202 Accepted even though the message would never be processed.
This change:
  • Drains buffered incoming messages when the server connection closes.
  • Checks the closed state before and after queue operations so close races return io.EOF or 400 session closed.
  • Adds regression tests for stale post-close reads and POST responses after close.
Tests:
  • go test ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server|Handler_DiscoverFallsBackToInitialize|ClientTransport_HTTPErrors|405AllowHeader)$' -count=20
  • go test -race ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server)$' -count=20
  • go vet ./...
  • go test ./... (the MCP package still has the pre-existing localhost protection failure where the 0.0.0.0 via localhost rejects evil.com case receives HTTP 200 instead of 403; all other packages pass)
@jstar0@openhands-agent
mcp: drain SSE messages when closing
44aeebb
Co-authored-by: openhands <openhands@all-hands.dev>
Sign up for freeto join this conversation on GitHub.
Already have an account?
Sign in to comment

Reviewers


No reviews


Assignees


No one assigned


Labels


None yet


Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

sse: Close does not drain incoming; Read can deliver stale messages after Close and POST can return false 202


1 participant

@jstar0

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
mcp: drain SSE messages when closing - #1192
Open
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Open
mcp: drain SSE messages when closing#1192
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Conversation
@jstar0
@jstar0jstar0
commented
Aug 23, 2026

Copy link


Copy Markdown

Contributor
Fixes#1191.
SSEServerTransport.Close previously closed the session signal without draining buffered client messages. Because Read and ServeHTTP select between the message queue and the closed signal, a closed session could deliver stale messages or acknowledge a POST with 202 Accepted even though the message would never be processed.
This change:
  • Drains buffered incoming messages when the server connection closes.
  • Checks the closed state before and after queue operations so close races return io.EOF or 400 session closed.
  • Adds regression tests for stale post-close reads and POST responses after close.
Tests:
  • go test ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server|Handler_DiscoverFallsBackToInitialize|ClientTransport_HTTPErrors|405AllowHeader)$' -count=20
  • go test -race ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server)$' -count=20
  • go vet ./...
  • go test ./... (the MCP package still has the pre-existing localhost protection failure where the 0.0.0.0 via localhost rejects evil.com case receives HTTP 200 instead of 403; all other packages pass)
@jstar0@openhands-agent
mcp: drain SSE messages when closing
44aeebb
Co-authored-by: openhands <openhands@all-hands.dev>
Sign up for freeto join this conversation on GitHub.
Already have an account?
Sign in to comment

Reviewers


No reviews


Assignees


No one assigned


Labels


None yet


Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

sse: Close does not drain incoming; Read can deliver stale messages after Close and POST can return false 202


1 participant

@jstar0

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
mcp: drain SSE messages when closing - #1192
Open
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Open
mcp: drain SSE messages when closing#1192
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Conversation
@jstar0
@jstar0jstar0
commented
Aug 23, 2026

Copy link


Copy Markdown

Contributor
Fixes#1191.
SSEServerTransport.Close previously closed the session signal without draining buffered client messages. Because Read and ServeHTTP select between the message queue and the closed signal, a closed session could deliver stale messages or acknowledge a POST with 202 Accepted even though the message would never be processed.
This change:
  • Drains buffered incoming messages when the server connection closes.
  • Checks the closed state before and after queue operations so close races return io.EOF or 400 session closed.
  • Adds regression tests for stale post-close reads and POST responses after close.
Tests:
  • go test ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server|Handler_DiscoverFallsBackToInitialize|ClientTransport_HTTPErrors|405AllowHeader)$' -count=20
  • go test -race ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server)$' -count=20
  • go vet ./...
  • go test ./... (the MCP package still has the pre-existing localhost protection failure where the 0.0.0.0 via localhost rejects evil.com case receives HTTP 200 instead of 403; all other packages pass)
@jstar0@openhands-agent
mcp: drain SSE messages when closing
44aeebb
Co-authored-by: openhands <openhands@all-hands.dev>
Sign up for freeto join this conversation on GitHub.
Already have an account?
Sign in to comment

Reviewers


No reviews


Assignees


No one assigned


Labels


None yet


Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

sse: Close does not drain incoming; Read can deliver stale messages after Close and POST can return false 202


1 participant

@jstar0

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
mcp: drain SSE messages when closing - #1192
Open
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Open
mcp: drain SSE messages when closing#1192
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Conversation
@jstar0
@jstar0jstar0
commented
Aug 23, 2026

Copy link


Copy Markdown

Contributor
Fixes#1191.
SSEServerTransport.Close previously closed the session signal without draining buffered client messages. Because Read and ServeHTTP select between the message queue and the closed signal, a closed session could deliver stale messages or acknowledge a POST with 202 Accepted even though the message would never be processed.
This change:
  • Drains buffered incoming messages when the server connection closes.
  • Checks the closed state before and after queue operations so close races return io.EOF or 400 session closed.
  • Adds regression tests for stale post-close reads and POST responses after close.
Tests:
  • go test ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server|Handler_DiscoverFallsBackToInitialize|ClientTransport_HTTPErrors|405AllowHeader)$' -count=20
  • go test -race ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server)$' -count=20
  • go vet ./...
  • go test ./... (the MCP package still has the pre-existing localhost protection failure where the 0.0.0.0 via localhost rejects evil.com case receives HTTP 200 instead of 403; all other packages pass)
@jstar0@openhands-agent
mcp: drain SSE messages when closing
44aeebb
Co-authored-by: openhands <openhands@all-hands.dev>
Sign up for freeto join this conversation on GitHub.
Already have an account?
Sign in to comment

Reviewers


No reviews


Assignees


No one assigned


Labels


None yet


Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

sse: Close does not drain incoming; Read can deliver stale messages after Close and POST can return false 202


1 participant

@jstar0

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
mcp: drain SSE messages when closing - #1192
Open
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Open
mcp: drain SSE messages when closing#1192
jstar0 wants to merge 1 commit into
modelcontextprotocol:mainfrom 
jstar0:fix/1191-sse-close-drain
Conversation
@jstar0
@jstar0jstar0
commented
Aug 23, 2026

Copy link


Copy Markdown

Contributor
Fixes#1191.
SSEServerTransport.Close previously closed the session signal without draining buffered client messages. Because Read and ServeHTTP select between the message queue and the closed signal, a closed session could deliver stale messages or acknowledge a POST with 202 Accepted even though the message would never be processed.
This change:
  • Drains buffered incoming messages when the server connection closes.
  • Checks the closed state before and after queue operations so close races return io.EOF or 400 session closed.
  • Adds regression tests for stale post-close reads and POST responses after close.
Tests:
  • go test ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server|Handler_DiscoverFallsBackToInitialize|ClientTransport_HTTPErrors|405AllowHeader)$' -count=20
  • go test -race ./mcp -run '^TestSSE(ServerConnCloseDrainsIncoming|ServerTransportServeHTTPAfterClose|Server)$' -count=20
  • go vet ./...
  • go test ./... (the MCP package still has the pre-existing localhost protection failure where the 0.0.0.0 via localhost rejects evil.com case receives HTTP 200 instead of 403; all other packages pass)
@jstar0@openhands-agent
mcp: drain SSE messages when closing
44aeebb
Co-authored-by: openhands <openhands@all-hands.dev>
Sign up for freeto join this conversation on GitHub.
Already have an account?
Sign in to comment

Reviewers


No reviews


Assignees


No one assigned


Labels


None yet


Projects


None yet


Milestone


No milestone


Development

Successfully merging this pull request may close these issues.

sse: Close does not drain incoming; Read can deliver stale messages after Close and POST can return false 202


1 participant

@jstar0