v0.34.0

The notebookutils release. The shim a Fabric notebook imports went from
partial and partly-wrong to the whole documented surface — 44 members across 8
namespaces, each exercised end to end — and closing it turned up ten defects
that unit tests could not see.

⚠️ Upgrade first for this

notebookutils.fs.rm(path) on a directory deleted the entire subtree.
OneLake's DELETE ignored ?recursive= completely, so a bare rm took the tree
with it. ADLS Gen2 answers 409 DirectoryNotEmpty; the emulator was more
destructive than the thing it emulates, on the one filesystem operation with no
undo. Fixed: a non-empty directory is now refused unless recurse=True.

Breaking changes

All are corrections toward Fabric's documented contract — a framework
introspects these signatures and refuses to start when a parameter name differs
— but code written against v0.33.0 may need edits.

v0.33.0	v0.34.0	Note
fs.put(path, content, overwrite=True)	put(file, content, overwrite=False)	default changed; an overwrite must now be asked for
fs.append(path, content)	append(file, content, createFileIfNotExists=False)
fs.head(path, maxBytes=)	head(file, max_bytes=)
fs.cp(src, dst) / mv	cp(src, dest) / mv
fs.rm(dir) removed subtrees	rm(path, recurse=False) refuses a non-empty directory	see above
lakehouse.get(lakehouseId)	get(name)	addressed by NAME, as documented; an id still resolves

Positional callers are mostly unaffected; callers passing these by keyword are
not.

Fixed

• fs.rm destroyed directory trees (above).
• session.stop() and session.restartPython() never worked inside a
  session. Both read environment variables that nothing in the tree ever set,
  so they raised "this is running outside a notebook session" — inside one.
  They are now bound per statement, because one agent serves many concurrent
  sessions and a process variable would let stop() in one notebook end
  another's.
• restartPython() left the session without display, displayHTML and
  %run. Those are kernel builtins on Fabric; a Python restart cannot remove
  them.
• A referenced notebook resolved builtin/ to its own folder. nbResPath
  means the ROOT notebook's resources, and nothing ever sent a root — so a
  notebook read different files depending on how it was started.
• A cell's language was classified and then ignored. The run loop sent
  everything that was not sql to the Python executor, so correct Scala failed
  with a Python SyntaxError pointing at the user's own code, and a
  %%configure block of JSON failed the same way.
• The long-running-operation Location header always said https://, so a
  client following it — the documented route to a result — could not reach an
  emulator started with -disable-tls.
• display() and displayHTML() were absent entirely, raising NameError
  on one of the most common lines in any Fabric notebook.

Added

• The whole documented notebookutils surface: 44 members over fs,
  notebook, credentials, lakehouse, runtime, session, udf and
  variableLibrary, with the documented parameter names in the documented
  order. Every member is exercised end to end, not merely present.
• help() on every module, plus getHelpString — the discovery mechanism
  Fabric's own fs page opens by documenting. Derived by introspection, so it
  cannot drift from the code.
• Notebook item management (create, get, list, update, delete,
  getDefinition, updateDefinition), lakehouse definition round-trips,
  udf.run, runtime.getCurrentWorkspaceId, fs.refreshMounts.
• display() publishes rich output under a kernel — text/html with a
  text/plain alternative — and prints without one. The shipped JupyterLab
  binds Fabric's display, not IPython's.
• Microsoft's own stubs are vendored (third_party/notebookutils-stubs/)
  and held beside the documentation, so where the two Microsoft sources
  disagree the divergence is computed rather than assumed.

Honest limits

display() renders a correct HTML table, not Fabric's interactive widget
with its chart views and inspect panel; no local front end can prove
equivalence with that. The Files mount is a point-in-time copy, not blobfuse.
%%configure is accepted and ignored, out loud. Scala, R and C# cells are
refused by name rather than mis-executed.

And the standing one: everything here is verified against Microsoft's published
contract, not against a tenant. It means conforms to the documentation — never
matches Fabric.