{"record":{"id":"c233080a9d603d48","repo":"alyssaxuu/screenity","slug":"content-script-injection-failed-for-tab-tabid","errorCode":null,"errorMessage":"content script injection failed for tab ${tabId}","messagePattern":"content script injection failed for tab (.+?)","errorType":"exception","errorClass":"Error","httpStatus":null,"severity":"error","filePath":"src/pages/Background/utils/executeScripts.js","lineNumber":64,"sourceCode":"  if (typeof tabId !== \"number\") return false;\n  const contentScripts = chrome.runtime.getManifest().content_scripts || [];\n  const files = contentScripts.flatMap((cs) => cs.js || []);\n  if (files.length === 0) return false;\n  try {\n    await chrome.scripting.executeScript({ target: { tabId }, files });\n    return true;\n  } catch {\n    return false;\n  }\n};\n\n// Pings first: a blind send to a loading tab hangs instead of erroring, which\n// is what made the popup take minutes. A resend would toggle the popup twice.\nexport const sendMessageEnsuringContentScript = async (tabId, message) => {\n  const { sendMessageTab } = await import(\"../tabManagement\");\n  if (!(await hasContentScript(tabId))) {\n    if (!(await injectContentScriptIntoTab(tabId))) {\n      throw new Error(`content script injection failed for tab ${tabId}`);\n    }\n  }\n  return sendMessageTab(tabId, message);\n};\n\n// Recently-used first. Sinks collapsed-group tabs without needing the\n// tabGroups permission to identify them.\nconst injectionPriority = (tab, focusedWindowId) => {\n  if (tab.active) return 0;\n  if (focusedWindowId != null && tab.windowId === focusedWindowId) return 1;\n  return 2;\n};\n\n// Skips the ~1MB re-parse when the script is already there. Only absence\n// reads \"Receiving end does not exist\", so any other reply means it is.\n// A timeout counts as absent. Injection is deduped by\n// window.__screenityContentBootstrapped, so guessing wrong costs one parse.\nconst hasContentScript = async (tabId, timeoutMs = PING_TIMEOUT_MS) => {","sourceCodeStart":46,"sourceCodeEnd":82,"githubUrl":"https://github.com/alyssaxuu/screenity/blob/512606387b8d07dda5e63bb428bd063f0a2a3ed0/src/pages/Background/utils/executeScripts.js#L46-L82","documentation":"sendMessageEnsuringContentScript first checks whether the extension content script is present in the target tab and, if not, injects it via injectContentScriptIntoTab. This error is thrown when the injection itself returns a falsy result, meaning the content script could not be established in the tab, so sending the message would hang or fail.","triggerScenarios":"Calling sendMessageEnsuringContentScript(tabId, message) for a tab where hasContentScript returns false and injectContentScriptIntoTab also fails — e.g. restricted pages (chrome://, Web Store, PDF viewer), discarded/sleeping tabs, tabs without host permissions, or the tab closing/navigating mid-injection.","commonSituations":"User clicks the popup while the active tab is a browser-internal page; extension updated but old content script absent and scripting permission/host grants missing; tab was put to sleep by a tab-suspender extension; MV3 service worker woke up after the tab navigated.","solutions":["Check the page URL before calling: skip restricted schemes (chrome://, edge://, chrome-extension://, about:) and surface a friendly 'this page is not supported' message instead of throwing.","Verify manifest host_permissions / optional_host_permissions cover the target origin and that the 'scripting' permission is granted.","Check tab status in the callback: if the tab is 'loading' or 'unloaded'/'discarded', wait for tabs.onUpdated status 'complete' or reload the tab, then retry once.","Confirm the content script file path passed to chrome.scripting.executeScript is correct and the file is web-accessible/registered.","Log the underlying chrome.runtime.lastError inside injectContentScriptIntoTab to see the real injection failure reason."],"exampleFix":"// before\nconst ok = await injectContentScriptIntoTab(tabId);\nif (!ok) {\n  throw new Error(`content script injection failed for tab ${tabId}`);\n}\n// after\nconst tab = await chrome.tabs.get(tabId);\nif (!/^https?:/.test(tab.url ?? \"\")) {\n  throw new Error(`cannot inject into restricted page: ${tab.url}`);\n}\nawait waitForTabComplete(tabId);\nconst ok = await injectContentScriptIntoTab(tabId);\nif (!ok) {\n  throw new Error(`content script injection failed for tab ${tabId}`);\n}","handlingStrategy":"try-catch","validationCode":"const tab = await chrome.tabs.get(tabId);\nconst injectable = /^https?:/.test(tab.url ?? \"\") && tab.status !== \"unloaded\";\nif (!injectable) throw new Error(`Cannot inject content script into ${tab.url}`);","typeGuard":"function isInjectableTab(tab) {\n  return typeof tab?.url === \"string\" && /^https?:/.test(tab.url);\n}","tryCatchPattern":"try {\n  await sendMessageEnsuringContentScript(tabId, message);\n} catch (err) {\n  if (String(err.message).startsWith(\"content script injection failed\")) {\n    showUnsupportedPageNotice(tabId);\n  } else {\n    throw err;\n  }\n}","preventionTips":["Check tab.url against restricted schemes before messaging","Declare host_permissions broadly or request optional host permissions for the active tab","Wait for tabs.onUpdated status 'complete' on freshly navigated tabs","Handle tab discard/sleep by reloading before injection"],"tags":["browser-extension","content-script","injection","chrome-scripting"],"backgroundTag":"content-script-injection-failed","analyzedSha":"512606387b8d07dda5e63bb428bd063f0a2a3ed0","analyzedAt":"2026-09-02T20:59:09.419Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-10T02:17:09.455Z"}