araised

Static analysis tool that answers: what exceptions can this function raise?

Analyses explicit raise statements and common stdlib callables (dict[key], open(), json.loads(), etc.) using Pyright for type inference. Propagates through same-module and cross-file call chains with cycle detection.

Installation

pip install araised

To install the latest development version directly from the dev branch:

uv tool install git+https://github.com/amirouche/raises.py@dev

Requires Pyright (pip install pyright), which is pulled in automatically as a dependency.

CLI

araised module.path:callable [module.path:callable ...]

The target is module.path:callable, where callable is a bare function name or ClassName.method_name.

$ araised myapp.db:connect
myapp.db:connect
  builtins.KeyError        [dict.__getitem__, step 1]
  builtins.ValueError      [explicit raise, step 2]
  builtins.OSError         [builtins.open, step 1, via myapp.db:connect → myapp.db:_open_file]

Each line shows the exception, where it comes from, the analysis step, and the call chain (via) if it was propagated from a callee.

Multiple targets can be passed in one invocation:

$ araised myapp.db:connect myapp.db:disconnect

Programmatic API

import araised

entries = araised.analyse('myapp.db:connect')
for e in entries:
    print(e.exception, e.source, e.step, e.via)

analyse returns a list of RaisesEntry namedtuples:

Optional parameters:

araised.analyse(
    'myapp.db:connect',
    max_depth=3,        # max cross-file hops (default 3, 0 = no cross-file)
    max_union_width=3,  # max union members for dynamic dispatch (default 3)
)

Emacs

Load araised.el and call araised-at-point with point inside any Python function or method. It infers the target from the current file and def automatically, then shows results in a *araised* buffer.

(load "/path/to/araised.el")

;; optional keybinding
(add-hook 'python-mode-hook
          (lambda () (local-set-key (kbd "C-c r") #'araised-at-point)))

With point inside a function, M-x araised-at-point (or C-c r) prompts:

araised target: myapp.db:connect

Edit the target if needed, then press RET. Results appear in *araised*.