Apply mention limits to output content instead of allowlists (#57747)

Author: Copilot

actions/setup/js/add_comment.cjs

@@ -11,7 +11,7 @@ const { getRepositoryUrl } = require("./get_repository_url.cjs");
 const { replaceTemporaryIdReferences, resolveSafeOutputIssueTarget } = require("./temporary_id.cjs");
 const { getTrackerID } = require("./get_tracker_id.cjs");
 const { getErrorMessage } = require("./error_helpers.cjs");
-const { parseBoolTemplatable } = require("./templatable.cjs");
+const { parseBoolTemplatable, parseIntTemplatable } = require("./templatable.cjs");
 const { resolveTarget, isStagedMode } = require("./safe_output_helpers.cjs");
 const { resolveTargetRepoConfig, resolveAndValidateRepo } = require("./repo_helpers.cjs");
 const { createAuthenticatedGitHubClient } = require("./handler_auth.cjs");
@@ -507,6 +507,7 @@ async function main(config = {}) {
   const mentionsDisabled = config.mentions === false || config.mentions?.enabled === false;
   const preResolvedMentionAliases = !mentionsDisabled ? normalizeMentionAliases(config.allowedMentionAliases) : [];
   const configuredMentionAliases = !mentionsDisabled ? normalizeMentionAliases(config.mentions?.allowed) : [];
+  const maxMentions = mentionsDisabled ? undefined : parseIntTemplatable(config.mentions?.max, 50);
 
   // Create an authenticated GitHub client. Uses config["github-token"] when set
   // (for cross-repository operations), otherwise falls back to the step-level github.
@@ -803,7 +804,7 @@ async function main(config = {}) {
 
     // Sanitize content to prevent injection attacks, allowing parent issue/PR/discussion authors
     // so they can be @mentioned in the generated comment.
-    processedBody = sanitizeContent(processedBody, { allowedAliases: allowedMentionAliases });
+    processedBody = sanitizeContent(processedBody, { allowedAliases: allowedMentionAliases, maxMentions });
 
     // Enforce max limits before processing (validates user-provided content)
     try {

actions/setup/js/close_discussion.cjs

@@ -13,6 +13,7 @@ const { createAuthenticatedGitHubClient } = require("./handler_auth.cjs");
 const { ERR_NOT_FOUND } = require("./error_codes.cjs");
 const { resolveNumberFromTemporaryId } = require("./temporary_id.cjs");
 const { resolveAllowedMentionsFromPayload } = require("./resolve_mentions_from_payload.cjs");
+const { parseIntTemplatable } = require("./templatable.cjs");
 const { resolveTargetRepoConfig, resolveAndValidateRepo } = require("./repo_helpers.cjs");
 
 /**
@@ -168,6 +169,7 @@ async function main(config = {}) {
   const maxCount = config.max || 10;
   const githubClient = await createAuthenticatedGitHubClient(config);
   const allowBody = config.allow_body !== false; // default true; false only when explicitly set to false
+  const maxMentions = parseIntTemplatable(config.mentions?.max, 50);
   let allowedMentionAliases = [];
   if (Array.isArray(config.allowedMentionAliases)) {
     allowedMentionAliases = config.allowedMentionAliases;
@@ -307,7 +309,7 @@ async function main(config = {}) {
           core.info("close_discussion: allow-body is false — closing without a comment");
         }
       } else if (item.body) {
-        const sanitizedBody = sanitizeContent(item.body, { allowedAliases: allowedMentionAliases });
+        const sanitizedBody = sanitizeContent(item.body, { allowedAliases: allowedMentionAliases, maxMentions });
         const comment = await addDiscussionComment(githubClient, discussion.id, sanitizedBody);
         core.info(`Added comment to discussion #${discussionNumber}: ${comment.url}`);
         commentUrl = comment.url;

actions/setup/js/collect_ndjson_output.cjs

@@ -34,6 +34,7 @@ async function main() {
 
     // Extract mentions configuration from validation config
     const mentionsConfig = validationConfig?.mentions || null;
+    const maxMentions = parseIntTemplatable(mentionsConfig?.max, 50);
 
     // Resolve allowed mentions for the output collector
     // This determines which @mentions are allowed in the agent output
@@ -43,7 +44,7 @@ async function main() {
     /** @type {number | undefined} */
     let maxBotMentions;
 
-    function validateFieldWithInputSchema(value, fieldName, inputSchema, lineNum) {
+    function validateFieldWithInputSchema(value, fieldName, inputSchema, lineNum, allowedAliasesSeen) {
       if (inputSchema.required && (value === undefined || value === null)) {
         return {
           isValid: false,
@@ -66,7 +67,7 @@ async function main() {
               error: `Line ${lineNum}: ${fieldName} must be a string`,
             };
           }
-          normalizedValue = sanitizeContent(value, { allowedAliases: allowedMentions, maxBotMentions });
+          normalizedValue = sanitizeContent(value, { allowedAliases: allowedMentions, maxMentions, maxBotMentions, allowedAliasesSeen });
           break;
         case "boolean":
           if (typeof value !== "boolean") {
@@ -97,11 +98,11 @@ async function main() {
               error: `Line ${lineNum}: ${fieldName} must be one of: ${inputSchema.options.join(", ")}`,
             };
           }
-          normalizedValue = sanitizeContent(value, { allowedAliases: allowedMentions, maxBotMentions });
+          normalizedValue = sanitizeContent(value, { allowedAliases: allowedMentions, maxMentions, maxBotMentions, allowedAliasesSeen });
           break;
         default:
           if (typeof value === "string") {
-            normalizedValue = sanitizeContent(value, { allowedAliases: allowedMentions, maxBotMentions });
+            normalizedValue = sanitizeContent(value, { allowedAliases: allowedMentions, maxMentions, maxBotMentions, allowedAliasesSeen });
           }
           break;
       }
@@ -120,9 +121,10 @@ async function main() {
           normalizedItem,
         };
       }
+      const allowedAliasesSeen = new Set();
       for (const [fieldName, inputSchema] of Object.entries(jobConfig.inputs)) {
         const fieldValue = item[fieldName];
-        const validation = validateFieldWithInputSchema(fieldValue, fieldName, inputSchema, lineNum);
+        const validation = validateFieldWithInputSchema(fieldValue, fieldName, inputSchema, lineNum, allowedAliasesSeen);
         if (!validation.isValid && validation.error) {
           errors.push(validation.error);
         } else if (validation.normalizedValue !== undefined) {
@@ -357,6 +359,7 @@ async function main() {
         if (hasValidationConfig(itemType)) {
           const validationResult = validateItem(item, itemType, i + 1, {
             allowedAliases: allowedMentions,
+            maxMentions,
             maxBotMentions,
             normalizeIssueClosingKeywords,
             dataEnabled: typeConfig !== null && typeof typeConfig === "object" && typeConfig.data_enabled === true,

actions/setup/js/collect_ndjson_output.test.cjs

@@ -1320,6 +1320,43 @@ describe("collect_ndjson_output.cjs", () => {
             parsedOutput = JSON.parse(outputCall[1]);
           expect(parsedOutput.items[0].body).toBe("Hey `@username` and `@org/team`, check this out! But preserve email@domain.com");
         }),
+        it("should preserve allowed aliases after max when no more than max occur", async () => {
+          const allowed = Array.from({ length: 60 }, (_, i) => `user${i}`);
+          const validationPath = "/tmp/gh-aw/safeoutputs/validation.json";
+          const validationConfig = JSON.parse(fs.readFileSync(validationPath, "utf8"));
+          validationConfig.mentions = { allowContext: false, allowed, max: 3 };
+          fs.writeFileSync(validationPath, JSON.stringify(validationConfig));
+
+          const testFile = "/tmp/gh-aw/test-ndjson-output.txt";
+          const ndjsonContent = '{"type":"create_issue","title":"Late allowlist entries","body":"Thanks @user57, @user58, and @user59"}';
+          fs.writeFileSync(testFile, ndjsonContent);
+          process.env.GH_AW_SAFE_OUTPUTS = testFile;
+          fs.writeFileSync("/tmp/gh-aw/safeoutputs/config.json", '{"create_issue":true}');
+
+          await eval(`(async () => { ${collectScript}; await main(); })()`);
+
+          const outputCall = mockCore.setOutput.mock.calls.find(call => call[0] === "output");
+          const parsedOutput = JSON.parse(outputCall[1]);
+          expect(parsedOutput.items[0].body).toBe("Thanks @user57, @user58, and @user59");
+        }),
+        it("should apply the mention limit across all fields in one item", async () => {
+          const validationPath = "/tmp/gh-aw/safeoutputs/validation.json";
+          const validationConfig = JSON.parse(fs.readFileSync(validationPath, "utf8"));
+          validationConfig.mentions = { allowContext: false, allowed: ["user1", "user2", "user3", "user4"], max: 3 };
+          fs.writeFileSync(validationPath, JSON.stringify(validationConfig));
+
+          const testFile = "/tmp/gh-aw/test-ndjson-output.txt";
+          fs.writeFileSync(testFile, '{"type":"create_issue","title":"@user1 @user2","body":"@user3 @user4 @user1"}');
+          process.env.GH_AW_SAFE_OUTPUTS = testFile;
+          fs.writeFileSync("/tmp/gh-aw/safeoutputs/config.json", '{"create_issue":true}');
+
+          await eval(`(async () => { ${collectScript}; await main(); })()`);
+
+          const outputCall = mockCore.setOutput.mock.calls.find(call => call[0] === "output");
+          const parsedOutput = JSON.parse(outputCall[1]);
+          expect(parsedOutput.items[0].title).toBe("@user1 @user2");
+          expect(parsedOutput.items[0].body).toBe("@user3 `@user4` @user1");
+        }),
         it("should neutralize bot trigger phrases", async () => {
           const testFile = "/tmp/gh-aw/test-ndjson-output.txt",
             ndjsonContent = '{"type": "create_issue", "title": "Bot Trigger Test", "body": "This fixes #123 and closes #456, also resolves #789"}';

actions/setup/js/create_discussion.cjs

@@ -26,7 +26,7 @@ const { tryEnforceArrayLimit } = require("./limit_enforcement_helpers.cjs");
 const { logStagedPreviewInfo } = require("./staged_preview.cjs");
 const { isStagedMode } = require("./safe_output_helpers.cjs");
 const { closeOlderDiscussions: closeOlderDiscussionsFunc } = require("./close_older_discussions.cjs");
-const { parseBoolTemplatable } = require("./templatable.cjs");
+const { parseBoolTemplatable, parseIntTemplatable } = require("./templatable.cjs");
 const { buildWorkflowRunUrl } = require("./workflow_metadata_helpers.cjs");
 const { generateHistoryLink, generateHistoryUrl } = require("./generate_history_link.cjs");
 const { MAX_LABELS } = require("./constants.cjs");
@@ -312,6 +312,7 @@ async function main(config = {}) {
   // Create an authenticated GitHub client. Uses config["github-token"] when set
   // (for cross-repository operations), otherwise falls back to the step-level github.
   const githubClient = await createAuthenticatedGitHubClient(config);
+  const maxMentions = parseIntTemplatable(config.mentions?.max, 50);
   let allowedMentionAliases = [];
   if (Array.isArray(config.allowedMentionAliases)) {
     allowedMentionAliases = config.allowedMentionAliases;
@@ -502,7 +503,7 @@ async function main(config = {}) {
     const preSanitizeBodyLength = processedBody.trim().length;
 
     // Sanitize body content to neutralize @mentions, URLs, and other security risks
-    processedBody = sanitizeContent(processedBody, { allowedAliases: allowedMentionAliases });
+    processedBody = sanitizeContent(processedBody, { allowedAliases: allowedMentionAliases, maxMentions });
     if (minBodyLength > 0 && preSanitizeBodyLength < minBodyLength) {
       const error = `Discussion body length ${preSanitizeBodyLength} is below configured minimum ${minBodyLength}`;
       core.error(error);

actions/setup/js/create_issue.cjs

@@ -20,7 +20,7 @@ const { renderTemplateFromFile } = require("./messages_core.cjs");
 const { createExpirationLine, addExpirationToFooter } = require("./ephemerals.cjs");
 const { MAX_SUB_ISSUES, getSubIssueCount, linkSubIssue } = require("./sub_issue_helpers.cjs");
 const { closeOlderIssues, searchOlderIssues, addIssueComment } = require("./close_older_issues.cjs");
-const { parseBoolTemplatable } = require("./templatable.cjs");
+const { parseBoolTemplatable, parseIntTemplatable } = require("./templatable.cjs");
 const { tryEnforceArrayLimit } = require("./limit_enforcement_helpers.cjs");
 const { logStagedPreviewInfo } = require("./staged_preview.cjs");
 const { isStagedMode } = require("./safe_output_helpers.cjs");
@@ -669,6 +669,7 @@ async function main(config = {}) {
   // Create an authenticated GitHub client. Uses config["github-token"] when set
   // (for cross-repository operations), otherwise falls back to the step-level github.
   const githubClient = await createAuthenticatedGitHubClient(config);
+  const maxMentions = parseIntTemplatable(config.mentions?.max, 50);
   let allowedMentionAliases = [];
   if (Array.isArray(config.allowedMentionAliases)) {
     allowedMentionAliases = config.allowedMentionAliases;
@@ -915,7 +916,7 @@ async function main(config = {}) {
     processedBody = removeDuplicateTitleFromDescription(title, processedBody);
 
     // Sanitize body content to neutralize @mentions, URLs, and other security risks
-    processedBody = sanitizeContent(processedBody, { allowedAliases: allowedMentionAliases });
+    processedBody = sanitizeContent(processedBody, { allowedAliases: allowedMentionAliases, maxMentions });
 
     const bodyLines = processedBody.split("\n");
 

actions/setup/js/create_pr_review_comment.cjs

@@ -12,6 +12,7 @@ const { createAuthenticatedGitHubClient } = require("./handler_auth.cjs");
 const { buildWorkflowRunUrl } = require("./workflow_metadata_helpers.cjs");
 const { isTemplatableTrue, isStagedMode, logStagedPreviewInfo, checkRequiredFilter } = require("./safe_output_helpers.cjs");
 const { resolveAllowedMentionsFromPayload } = require("./resolve_mentions_from_payload.cjs");
+const { parseIntTemplatable } = require("./templatable.cjs");
 const { resolveInvocationContext } = require("./invocation_context_helpers.cjs");
 const { ERR_VALIDATION } = require("./error_codes.cjs");
 
@@ -58,6 +59,7 @@ async function main(config = {}) {
   if (requiredLabels.length > 0) core.info(`Required labels (all): ${requiredLabels.join(", ")}`);
   if (requiredTitlePrefix) core.info(`Required title prefix: ${requiredTitlePrefix}`);
 
+  const maxMentions = parseIntTemplatable(config.mentions?.max, 50);
   let allowedMentionAliases = [];
   if (Array.isArray(config.allowedMentionAliases)) {
     allowedMentionAliases = config.allowedMentionAliases;
@@ -376,7 +378,7 @@ async function main(config = {}) {
     const bufferedComment = {
       path: commentItem.path,
       line: line,
-      body: sanitizeContent(commentItem.body.trim(), { allowedAliases: allowedMentionAliases }),
+      body: sanitizeContent(commentItem.body.trim(), { allowedAliases: allowedMentionAliases, maxMentions }),
       side: side,
     };
 

actions/setup/js/create_project_status_update.cjs

@@ -10,6 +10,7 @@ const { isTemporaryId, normalizeTemporaryId } = require("./temporary_id.cjs");
 const { ERR_CONFIG, ERR_NOT_FOUND, ERR_PARSE, ERR_VALIDATION } = require("./error_codes.cjs");
 const { logGraphQLError } = require("./github_api_helpers.cjs");
 const { resolveAllowedMentionsFromPayload } = require("./resolve_mentions_from_payload.cjs");
+const { parseIntTemplatable } = require("./templatable.cjs");
 
 /**
  * @typedef {import('./types/handler-factory').HandlerFactoryFunction} HandlerFactoryFunction
@@ -273,6 +274,7 @@ async function main(config = {}, githubClient = null) {
   if (!github) {
     throw new Error(`${ERR_CONFIG}: GitHub client is required but not provided. Either pass a github client to main() or ensure global.github is set by github-script action.`);
   }
+  const maxMentions = parseIntTemplatable(config.mentions?.max, 50);
   let allowedMentionAliases = [];
   if (Array.isArray(config.allowedMentionAliases)) {
     allowedMentionAliases = config.allowedMentionAliases;
@@ -367,7 +369,7 @@ async function main(config = {}, githubClient = null) {
       const status = validateStatus(output.status);
       const startDate = formatDate(output.start_date);
       const targetDate = formatDate(output.target_date);
-      const body = sanitizeContent(String(output.body), { allowedAliases: allowedMentionAliases });
+      const body = sanitizeContent(String(output.body), { allowedAliases: allowedMentionAliases, maxMentions });
 
       core.info(`Creating status update: ${status} (${startDate} → ${targetDate})`);
       core.info(`Body preview: ${body.substring(0, 100)}${body.length > 100 ? "..." : ""}`);

actions/setup/js/create_pull_request.cjs

@@ -16,7 +16,7 @@ const { replaceTemporaryIdReferences, replaceTemporaryIdReferencesInPatch, getOr
 const { resolveTargetRepoConfig, resolveAndValidateRepo } = require("./repo_helpers.cjs");
 const { addExpirationToFooter } = require("./ephemerals.cjs");
 const { generateWorkflowIdMarker, generateWorkflowCallIdMarker, generateCloseKeyMarker, normalizeCloseOlderKey } = require("./generate_footer.cjs");
-const { parseBoolTemplatable } = require("./templatable.cjs");
+const { parseBoolTemplatable, parseIntTemplatable } = require("./templatable.cjs");
 const { assembleMarkdownBodyParts } = require("./markdown_body_helpers.cjs");
 const { getBodyHeader, getDisclosureHeader } = require("./messages_header.cjs");
 const { generateHistoryUrl } = require("./generate_history_link.cjs");
@@ -782,6 +782,7 @@ async function main(config = {}) {
   // Tracks the pull requests created so far in this run so later messages can stack on top of them.
   const stackTracker = createStackTracker();
   const githubClient = await createAuthenticatedGitHubClient(config);
+  const maxMentions = parseIntTemplatable(config.mentions?.max, 50);
   let allowedMentionAliases = [];
   if (Array.isArray(config.allowedMentionAliases)) {
     allowedMentionAliases = config.allowedMentionAliases;
@@ -1504,7 +1505,7 @@ async function main(config = {}) {
       processedBody = removeDuplicateTitleFromDescription(title, processedBody);
 
       // Sanitize body content to neutralize @mentions, URLs, and other security risks
-      processedBody = sanitizeContent(processedBody, { allowedAliases: allowedMentionAliases });
+      processedBody = sanitizeContent(processedBody, { allowedAliases: allowedMentionAliases, maxMentions });
 
       // Auto-add "Fixes #N" closing keyword if triggered from an issue and not already present.
       // This ensures the triggering issue is auto-closed when the PR is merged.
@@ -1898,7 +1899,7 @@ async function main(config = {}) {
                   baseBranch,
                   tempRef: createBundleTempRef(branchName),
                 });
-                const pushFailureMessage = sanitizeContent(neutralizeClosingKeywordsForIssueBody(getErrorMessage(pushError)), { allowedAliases: allowedMentionAliases })
+                const pushFailureMessage = sanitizeContent(neutralizeClosingKeywordsForIssueBody(getErrorMessage(pushError)), { allowedAliases: allowedMentionAliases, maxMentions })
                   .replace(/\s+/g, " ")
                   .trim();
                 const pushErrorSection = buildPushErrorSection(getErrorMessage(pushError), pushFailureMessage);
@@ -2267,7 +2268,7 @@ gh pr create --title ${shellQuote(title)} --base ${shellQuote(baseBranch)} --hea
                   branchName,
                   baseBranch,
                 });
-                const pushFailureMessage = sanitizeContent(neutralizeClosingKeywordsForIssueBody(getErrorMessage(pushError)), { allowedAliases: allowedMentionAliases })
+                const pushFailureMessage = sanitizeContent(neutralizeClosingKeywordsForIssueBody(getErrorMessage(pushError)), { allowedAliases: allowedMentionAliases, maxMentions })
                   .replace(/\s+/g, " ")
                   .trim();
                 const pushErrorSection = buildPushErrorSection(getErrorMessage(pushError), pushFailureMessage);