unsloth/docker/unsloth_colab_compat.py
2026-07-19 15:32:20 +00:00

99 lines
3.8 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-Present the Unsloth team. See /studio/LICENSE.AGPL-3.0
"""Colab cell-magic compatibility for the Unsloth Docker notebooks.
Colab cells often look like:
#@title Colab Extra Install { display-mode: "form" }
%%capture
!pip install ...
In IPython a cell magic (`%%capture`, `%%bash`, ...) is only recognised when it
is the VERY FIRST line of the cell. A leading Colab `#@title`/`#@param` form (or
any comment/blank line) pushes the `%%magic` to line 2, so IPython treats it as a
line magic and raises `UsageError: Line magic function `%%capture` not found.`
and the cell fails.
Fix: register an `input_transformers_cleanup` (runs before magic detection) that
hoists a `%%` cell magic above any leading blank/comment (`#...`, incl. `#@...`)
lines, so the magic lands on line 0 and fires normally. The skipped comment lines
stay in the cell (still inert), just below the magic -- so `%%capture` now also
captures them. Idempotent and fully guarded: any problem returns the input
unchanged, so a cell never breaks because of this helper.
The hoist is restricted to cell magics whose body is executed as code (Python or
shell), where a moved-down `#@title`/comment line stays an inert comment. Magics
that treat the body as literal content (`%%writefile`, `%%file`, `%%html`,
`%%javascript`, `%%latex`, `%%markdown`, `%%svg`, ...) are left untouched: moving
the Colab form comment into their body would write/render it and corrupt the
generated file or output.
This mirrors unsloth_nb_compat.register_ipython(): it is wired from the baked
IPython startup file (docker/unsloth_ipython_startup.py).
"""
from __future__ import annotations
import sys
# Cell magics whose body runs as code, so a hoisted comment stays inert. Only
# these; content/data magics (%%writefile, %%html, ...) untouched (see docstring).
_SAFE_CELL_MAGICS = frozenset(
{
"capture", # Colab install pattern: suppress pip output
"time",
"timeit",
"prun",
"debug",
"bash",
"sh",
"shell",
"python",
"python2",
"python3",
"pypy",
}
)
def colab_cell_magic_fix(lines):
"""Hoist a safe `%%` cell magic above leading blank/comment lines.
`lines` is the IPython cell as a list of strings (each ending in '\\n').
Returns a (possibly reordered) list of the same lines.
"""
try:
skipped = []
for i, line in enumerate(lines):
stripped = line.strip()
if stripped == "" or stripped.startswith("#"):
skipped.append(line) # blank or comment (incl. #@title)
continue
# First real line. Act only if it's a cell magic not already on top.
if stripped.startswith("%%") and i > 0:
name = stripped[2:].split(maxsplit = 1)
name = name[0] if name else ""
if name in _SAFE_CELL_MAGICS:
return [line] + skipped + lines[i + 1 :]
# Content/data magic: don't move the comment into its body.
return lines
return lines # already on top, or not a magic
return lines # all blank/comment -> nothing to do
except Exception:
return lines
def register_ipython():
"""Append the transformer to the running IPython (called from startup)."""
try:
ip = get_ipython() # noqa: F821 (provided by IPython)
except NameError:
return
if ip is None or getattr(ip, "_unsloth_colab_fix", False):
return
try:
ip.input_transformers_cleanup.append(colab_cell_magic_fix)
ip._unsloth_colab_fix = True
except Exception as e: # never break a kernel because of the helper
print(f"[unsloth-nb] colab-compat hook skipped: {e!r}", file = sys.stderr)