Upload cache fixes

[pboguslawski]

Proposed change

This mod fixes the following upload cache problems:

(1)
If one uploads many files (dropping files test0.bin-test9.bin in one move) races may occur and file id in DOM won't match file ids in web upload dir on server, i.e.:

$(".AttachmentListContainer tbody tr").filter(function() { console.log("%s, %d", $(this).find('td.Filename').text(), $(this).find('a').data('file-id'))})
test9.bin, 10
test8.bin, 8
test7.bin, 8
test6.bin, 7
test5.bin, 4
test4.bin, 5
test3.bin, 3
test2.bin, 3
test1.bin, 2
test0.bin, 1

This may be fixed with patch (which unblocks updating all file ids on upload not just for one file)...

--- a/var/httpd/htdocs/js/Core.UI.js   2021-11-08 18:53:34.088284466 +0100
+++ b/var/httpd/htdocs/js/Core.UI.js 2021-12-16 18:41:14.090199778 +0100
@@ -697,10 +697,6 @@
 
                                 $TargetObj = $ExistingItemObj.closest('tr');
 
-                                if ($TargetObj.find('a').data('file-id')) {
-                                    return;
-                                }
-
                                 $TargetObj
                                     .find('.Filetype')
                                     .text(Attachment.ContentType)

...but using file ids for identification of uploaded files is not race condition resistant; to provoke race condition apply patch

--- a/Kernel/Modules/AjaxAttachment.pm 2021-06-19 21:59:34.379471088 +0200
+++ b/Kernel/Modules/AjaxAttachment.pm       2021-12-16 18:38:28.943925139 +0100
@@ -56,6 +56,10 @@
             Param => 'Files',
         );
 
+        if ($UploadStuff{Filename} eq 'test01.bin') {
+            sleep(1);
+        }
+
         $UploadCacheObject->FormIDAddFile(
             FormID      => $Self->{FormID},
             Disposition => 'attachment',
@@ -67,6 +71,10 @@
             FormID => $Self->{FormID},
         );
 
+        if ($UploadStuff{Filename} eq 'test02.bin') {
+            sleep(2);
+        }
+
         my @AttachmentData;

and drop files test01.bin and test02.bin (same size) in one move; after upload there will be:

$(".AttachmentListContainer tbody tr").filter(function() { console.log("%s, %d", $(this).find('td.Filename').text(), $(this).find('a').data('file-id'))})
test02.bin, 1
test01.bin, 1

not

test02.bin, 2
test01.bin, 1

This problem was solved by removing unnecessary FileID attribute from upload data struct to avoid any races that may occur between filename list and fileid list. Only filename will be used to identify items added to upload cache.

This bug is dangerous - think about uploading some confidential stuff by mistake, then removing it (disappears from UI) and sending message with different set of files than displayed in UI (i.e. with confidential stuff that user wanted to remove).

(2)
Double clicking trash icon to remove attachment generates two requests to server and one will cause an error.

(3)
Unused upload handling code removed.

Type of change

• '1 - 🐞 bug 🐞' - Bugfix (non-breaking change which fixes an issue)

Breaking change

Removes FileID attribute from web upload cache objects to avoid races.

Additional information

Replaces: #179
Author-Change-Id: IB#1113065

Checklist

• The code change is tested and works locally.(❗)
• There is no commented out code in this PR.(❕)
• You improved or added new unit tests.(❕)
• Local ZnunyCodePolicy run passes successfully.(❕)
• Local unit tests pass.(❕)
• GitHub workflow ZnunyCodePolicy passes.(❗)
• GitHub workflow unit tests pass.(❗)