`inspect.{getsourcelines, findsource}` return 0 as the starting line number for modules

[artemmukhin]

Bug report

Run the following program

import inspect
import inspect
_, lineno1 = inspect.getsourcelines(inspect.currentframe())
_, lineno2 = inspect.findsource(inspect.currentframe())
print(lineno1, lineno2)

Expected Result
The line numbers are expected to be 1-based, so the expected output is 1 1.

Actual Result
The actual output is 0 0.

Related discussion: #103226

Your environment

• CPython versions tested on: main branch
• Operating system and architecture: macOS

Linked PRs

• GH-103319: Fix inspect.getsourcelines() to return 1-based line numbers #103226

[George-Ogden]

inspect.getsourcelines(frame) seems to return the 1-based index or 0 (when the whole file is returned).

Here are some examples:

frame = inspect.currentframe()
inspect.getsourcelines(frame) # _, 0

def foo(): # start of file
    import inspect
    frame = inspect.currentframe()
    inspect.getsourcelines(frame) # _, 1

foo()

import inspect

...

def bar():
    frame = inspect.currentframe()
    inspect.getsourcelines(frame) # _, n (1-based index)

bar()

Currently, I work around this with:

source, offset = inspect.getsourcelines(frame)
offset = max(1, offset)