XWikiAttachment#isMetaDataDirty() is not honored when saving an attachment

When programmatically creating a new attachment using the FS attachments store, there is no way to save the attachment with a specific date (as it can be done with XWikiDocuments) : even though a date can be set using XWikiAttachment#setDate(Date) along with XWikiAttachment#setMetaDataDirty(false) (so that metadatas do not get updated when saving the attachment), the date that has been set will overwritten with the current date at save time.

Looking a bit more at the issue, this seems to come from https://github.com/xwiki/xwiki-platform/blob/eb0d7128deb7596f824d8e2f008dade8f54e6ba1/xwiki-platform-core/xwiki-platform-store/xwiki-platform-store-filesystem-oldcore/src/main/java/org/xwiki/store/legacy/doc/internal/ListAttachmentArchive.java#L299 ; ListAttachmentArchive#update() is called during the save of the attachment and does not check for XWikiAttachment#isMetaDataDirty() before increasing the attachment version and updating the attachment date.

To get this issue, here is an extract of the code used :

{{groovy}}
// pageDoc is a Document
// attachmentIS is an InputStream

def attach = pageDoc.addAttachment("MyAttachment.png", attachmentIS)
attach.getAttachment().setAuthor("xwiki:XWiki.Admin")
attach.getAttachment().setDate(myDate);
attach.getAttachment().setMetaDataDirty(false);

// Save the doc …
{{/groovy}}