Based on @pourhaus answer (from 2014), this recipe augments the pdb++ debugger with a reload command (expected to work on both Linux & Windows, on any Python installation).
TIP: the new reload command accepts an optional list of module-prefixes to reload (and to exclude), not to break already loaded globals when resuming debugging.
Just insert the following Python-3.6 code into your ~/.pdbrc.py file:
## Augment `pdb++` with a `reload` command
#
# See https://mcmap.net/q/580705/-how-to-make-pdb-recognize-that-the-source-has-changed-between-runs/64194585#64194585
from pdb import Pdb
def _pdb_reload(pdb, modules):
"""
Reload all non system/__main__ modules, without restarting debugger.
SYNTAX:
reload [<reload-module>, ...] [-x [<exclude-module>, ...]]
* a dot(`.`) matches current frame's module `__name__`;
* given modules are matched by prefix;
* any <exclude-modules> are applied over any <reload-modules>.
EXAMPLES:
(Pdb++) reload # reload everything (brittle!)
(Pdb++) reload myapp.utils # reload just `myapp.utils`
(Pdb++) reload myapp -x . # reload `myapp` BUT current module
"""
import importlib
import sys
## Derive sys-lib path prefix.
#
SYS_PREFIX = importlib.__file__
SYS_PREFIX = SYS_PREFIX[: SYS_PREFIX.index("importlib")]
## Parse args to decide prefixes to Include/Exclude.
#
has_excludes = False
to_include = set()
# Default prefixes to Exclude, or `pdb++` will break.
to_exclude = {"__main__", "pdb", "fancycompleter", "pygments", "pyrepl"}
for m in modules.split():
if m == "-x":
has_excludes = True
continue
if m == ".":
m = pdb._getval("__name__")
if has_excludes:
to_exclude.add(m)
else:
to_include.add(m)
to_reload = [
(k, v)
for k, v in sys.modules.items()
if (not to_include or any(k.startswith(i) for i in to_include))
and not any(k.startswith(i) for i in to_exclude)
and getattr(v, "__file__", None)
and not v.__file__.startswith(SYS_PREFIX)
]
print(
f"PDB-reloading {len(to_reload)} modules:",
*[f" +--{k:28s}:{getattr(v, '__file__', '')}" for k, v in to_reload],
sep="\n",
file=sys.stderr,
)
for k, v in to_reload:
try:
importlib.reload(v)
except Exception as ex:
print(
f"Failed to PDB-reload module: {k} ({v.__file__}) due to: {ex!r}",
file=sys.stderr,
)
Pdb.do_reload = _pdb_reload
