tools: add mailmap support for Co-authored-by tags

Support `.mailmap` for manually added `Author:` and
`Co-authored-by:` tags.
PR-URL: #26383
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

Author: addaleax

tools/update-authors.js

@@ -3,6 +3,7 @@
 // Passing --dry will redirect output to stdout rather than write to 'AUTHORS'.
 'use strict';
 const{ spawn }=require('child_process');
+constpath=require('path');
 constfs=require('fs');
 constreadline=require('readline');
 
@@ -22,6 +23,38 @@ else
 
 output.write('# Authors ordered by first contribution.\n\n');
 
+constmailmap=newMap();
+{
+constlines=fs.readFileSync(path.resolve(__dirname,'../','.mailmap'),
+{encoding: 'utf8'}).split('\n');
+for(letlineoflines){
+line=line.trim();
+if(line.startsWith('#')||line==='')continue;
+
+letmatch;
+// Replaced Name <original@example.com>
+if(match=line.match(/^([^<]+)\s+(<[^>]+>)$/)){
+mailmap.set(match[2],{author: match[1]});
+// <replaced@example.com> <original@example.com>
+}elseif(match=line.match(/^<([^>]+)>\s+(<[^>]+>)$/)){
+mailmap.set(match[2],{email: match[1]});
+// Replaced Name <replaced@example.com> <original@example.com>
+}elseif(match=line.match(/^([^<]+)\s+(<[^>]+>)\s+(<[^>]+>)$/)){
+mailmap.set(match[3],{
+author: match[1],email: match[2]
+});
+// Replaced Name <replaced@example.com> Original Name <original@example.com>
+}elseif(match=
+line.match(/^([^<]+)\s+(<[^>]+>)\s+([^<]+)\s+(<[^>]+>)$/)){
+mailmap.set(match[3]+'\0'+match[4],{
+author: match[1],email: match[2]
+});
+}else{
+console.warn('Unknown .mailmap format:',line);
+}
+}
+}
+
 constseen=newSet();
 
 // Support regular git author metadata, as well as `Author:` and
@@ -34,7 +67,13 @@ rl.on('line', (line) => {
 constmatch=line.match(authorRe);
 if(!match)return;
 
-const{ author, email }=match.groups;
+let{ author, email }=match.groups;
+
+constreplacement=mailmap.get(author+'\0'+email)||mailmap.get(email);
+if(replacement){
+({ author, email }={ author, email, ...replacement});
+}
+
 if(seen.has(email)||
 /@chromium\.org/.test(email)||
 email==='<erik.corry@gmail.com>'){