#libraries 12 articles

• MajorVersionLimit: 0 means unlimited, not nonegotchas / listsOne integer covering "no limit", "keep n" and "versioning is off"; the library your report calls tidiest is the one eating the quota
• Overwrite=true into a folder shared by many records silently replaces — and takes over — another record's filegotchas / rest-apiUploading with Files/AddUsingPath(…,Overwrite=true) under a user-supplied file name into a folder that holds documents of many records (cases, orders, tickets) lets a second file with the same generic name (such as…
• A drop box for sensitive files — a document library can't do it, a list with ReadSecurity 2 and attachments can (measured, including the direct attachment URL)gotchas / permissionsGiving someone write access to a protected library folder also lets them read every file in it; a list with ReadSecurity = 2, Contribute for the senders and Edit for the reviewers lets people send files they alone can…
• A library your app provisions inherits the web's write permissions — and that is how an AI grounding source gets poisonedgotchas / securityAny member can upload over REST and poison an AI grounded on that library; WriteSecurity: 4 does not fix it (Edit includes Manage Lists and bypasses item-level settings) — only unique permissions on the library do
• A version is a full copy, not a delta — and a metadata-only edit costs onegotchas / listsThe quota counts every version at full file size and a metadata-only edit costs one; measured on a live tenant, three column edits took a 1 MiB file to 4 MB
• An .html file in a document library cannot be iframed — SharePoint serves it as a downloadgotchas / listsSharePoint serves library HTML as an attachment, so the iframe loads empty; host it elsewhere and allow that host in HTML Field Security
• An image upload that accepts image/* accepts SVG — and SVG is a scriptgotchas / securitySVG is a script: inert inside , executed when the file's own URL is opened; allow-list raster MIME types
• File size in a document library — File_x0020_Size 400s; use $expand=Filegotchas / rest-apiFile_x0020_Size 400s in $select; use File/Length
• Multi-line text in a document library stops at 255 charactersgotchas / listsA REST MERGE stores 70k characters, but ValidateUpdateListItem rejects anything over 255 unless the column has UnlimitedLengthInDocumentLibrary – set it at creation or PATCH it later
• Search ParentLink points at a library view, not at the librarygotchas / searchOften …/Forms/AllItems.aspx, so used as a path it empties a Path: filter and can send a save into Forms while a GetList probe still passes; normalize on read and on write
• Turn a library URL someone pasted into web + library + foldersnippets / restSP.Web.GetWebUrlFromPageUrl, called on the CURRENT web, resolves the web of any URL in the tenant (other site collections too, 404 for a missing site); strip Forms/…aspx, prefer the ?id= folder, take the first segment…
• Uploaded .html grows after you set column values — SharePoint injects mso document properties (and rewrites Office files on upload)gotchas / rest-apiSetting column values rewrites the file; hash read-back fails for markup, holds for PDF; Office packages change on upload itself…