--- a/mercurial/archival.py	Thu Sep 05 13:37:24 2024 +0200
+++ b/mercurial/archival.py	Wed Nov 15 22:11:34 2023 +0100
@@ -293,8 +293,9 @@
 ):
     """create archive of repo as it was at node.
 
-    dest can be name of directory, name of archive file, or file
-    object to write archive to.
+    dest can be name of directory, name of archive file, a callable, or file
+    object to write archive to. If it is a callable, it will called to open
+    the actual file object before the first archive member is written.
 
     kind is type of archive to create.
 
@@ -316,7 +317,37 @@
     else:
         prefix = tidyprefix(dest, kind, prefix)
 
+    archiver = None
+    ctx = repo[node]
+
+    def opencallback():
+        """Return the archiver instance, creating it if necessary.
+
+        This function is called when the first actual entry is created.
+        It may be called multiple times from different layers.
+        When serving the archive via hgweb, no errors should happen after
+        this point.
+        """
+        nonlocal archiver
+        if archiver is None:
+            if callable(dest):
+                output = dest()
+            else:
+                output = dest
+            archiver = archivers[kind](output, mtime or ctx.date()[0])
+            assert archiver is not None
+
+            if repo.ui.configbool(b"ui", b"archivemeta"):
+                metaname = b'.hg_archival.txt'
+                if match(metaname):
+                    write(metaname, 0o644, False, lambda: buildmetadata(ctx))
+        return archiver
+
     def write(name, mode, islink, getdata):
+        if archiver is None:
+            opencallback()
+        assert archiver is not None, "archive should be opened by now"
+
         data = getdata()
         if decode:
             data = repo.wwritedata(name, data)
@@ -325,17 +356,9 @@
     if kind not in archivers:
         raise error.Abort(_(b"unknown archive type '%s'") % kind)
 
-    ctx = repo[node]
-    archiver = archivers[kind](dest, mtime or ctx.date()[0])
-
     if not match:
         match = scmutil.matchall(repo)
 
-    if repo.ui.configbool(b"ui", b"archivemeta"):
-        name = b'.hg_archival.txt'
-        if match(name):
-            write(name, 0o644, False, lambda: buildmetadata(ctx))
-
     files = list(ctx.manifest().walk(match))
     total = len(files)
     if total:
@@ -358,10 +381,11 @@
             sub = ctx.workingsub(subpath)
             submatch = matchmod.subdirmatcher(subpath, match)
             subprefix = prefix + subpath + b'/'
-            total += sub.archive(archiver, subprefix, submatch, decode)
+            total += sub.archive(opencallback, subprefix, submatch, decode)
 
     if total == 0:
         raise error.Abort(_(b'no files match the archive pattern'))
 
+    assert archiver is not None, "archive should have been opened before"
     archiver.done()
     return total