Fix mentions extractions with punctuations

Also don't consume spaces in regex, resulting in broken mention
extractions

packages/tests/src/server-helpers/mentions.ts

@@ -1,7 +1,7 @@
 /* oxlint-disable @typescript-eslint/no-unused-expressions,@typescript-eslint/require-await */
 
 import { expect } from 'chai'
-import { extractMentions } from '@peertube/peertube-server/core/helpers/mentions.js'
+import { extractLocalMentions } from '@peertube/peertube-server/core/helpers/mentions.js'
 
 describe('Comment model', function () {
   it('Should correctly extract mentions', async function () {
@@ -10,8 +10,13 @@ describe('Comment model', function () {
 
     const isLocal = true
 
-    const result = extractMentions(text, isLocal).sort((a, b) => a.localeCompare(b))
+    const result = extractLocalMentions(text, isLocal)
 
-    expect(result).to.deep.equal([ 'another', 'chocobozzz', 'end', 'flo', 'florian', 'jean' ])
+    expect(result).to.deep.equal([ 'florian', 'jean', 'flo', 'another', 'chocobozzz', 'end' ])
+  })
+
+  it('Should correctly extract mentions with adjacent punctuations and newlines', async function () {
+    expect(extractLocalMentions('thanks @bob!', true)).to.deep.equal([ 'bob' ])
+    expect(extractLocalMentions('@bob\n', true)).to.deep.equal([ 'bob' ])
   })
 })

server/core/helpers/mentions.ts

@@ -3,38 +3,16 @@ import { WEBSERVER } from '@server/initializers/constants.js'
 import { actorNameAlphabet } from './custom-validators/activitypub/actor.js'
 import { regexpCapture } from './regexp.js'
 
-export function extractMentions (text: string, isLocal: boolean) {
-  let result: string[] = []
+export function extractLocalMentions (text: string, fromLocalEntity: boolean) {
+  const setHostOptionalChar = fromLocalEntity
+    ? '?'
+    : ''
 
-  const localMention = `@(${actorNameAlphabet}+)`
-  const remoteMention = `${localMention}@${WEBSERVER.HOST}`
+  // FIXME: Use RegExp.escape() when NodeJS 24 is the minimum version required by peertube
+  const mentionRegex = new RegExp(`(?<=^|\\s)@(${actorNameAlphabet}+)(?:@${WEBSERVER.HOST})${setHostOptionalChar}(?=[\\s.,!?)]|$)`, 'gmu')
 
-  const mentionRegex = isLocal
-    ? '(?:(?:' + remoteMention + ')|(?:' + localMention + '))' // Include local mentions?
-    : '(?:' + remoteMention + ')'
-
-  const firstMentionRegex = new RegExp(`^${mentionRegex} `, 'g')
-  const endMentionRegex = new RegExp(` ${mentionRegex}$`, 'g')
-  const remoteMentionsRegex = new RegExp(' ' + remoteMention + ' ', 'g')
-
-  result = result.concat(
-    regexpCapture(text, firstMentionRegex)
-      .map(([ , username1, username2 ]) => username1 || username2),
-    regexpCapture(text, endMentionRegex)
-      .map(([ , username1, username2 ]) => username1 || username2),
-    regexpCapture(text, remoteMentionsRegex)
+  const results = regexpCapture(text, mentionRegex)
     .map(([ , username ]) => username)
-  )
 
-  // Include local mentions
-  if (isLocal) {
-    const localMentionsRegex = new RegExp(' ' + localMention + ' ', 'g')
-
-    result = result.concat(
-      regexpCapture(text, localMentionsRegex)
-        .map(([ , username ]) => username)
-    )
-  }
-
-  return uniqify(result)
+  return uniqify(results)
 }

server/core/models/video/video-comment.ts

@@ -9,7 +9,7 @@ import {
 } from '@peertube/peertube-models'
 import { afterCommitIfTransaction, retryTransactionWrapper } from '@server/helpers/database-utils.js'
 import { logger } from '@server/helpers/logger.js'
-import { extractMentions } from '@server/helpers/mentions.js'
+import { extractLocalMentions } from '@server/helpers/mentions.js'
 import { sequelizeTypescript } from '@server/initializers/database.js'
 import { getLocalApproveReplyActivityPubUrl } from '@server/lib/activitypub/url.js'
 import { getServerActor } from '@server/models/application/application.js'
@@ -698,7 +698,7 @@ export class VideoCommentModel extends SequelizeModel<VideoCommentModel> {
   }
 
   extractMentions () {
-    return extractMentions(this.text, this.isLocal())
+    return extractLocalMentions(this.text, this.isLocal())
   }
 
   toFormattedJSON (this: MCommentFormattable) {