Overwriting output files if they already exist

[rtpg]

Is there an existing proposal for this?

• I have searched the existing proposals

Is your feature request related to a problem?

If I put something like:

with memray.Tracker("out.bin"):
    .... # do thing

in a script, the first time I run it memray will glady write out to out.bin. The second time I run it, memray complains about out.bin already existing. So I need to throw in a Path("out.bin").unlink(error_ok=True) to have my script run the first and subsequent times.

This is also true on CLI invocations like memray run -o out.bin ... and memray flamegraph -o report.html ...

Describe the solution you'd like

If I specify an output file that already exists, I would expect it to "just" overwrite it! This is how many other "write profiling/debugging results to disk" utilities work, generally on the assumption that you run it over and over again.

"I have accidentally stated an existing file" seems like a rare occurence compared to "I would like to write to the same path with fresh data". To me anyways.

Alternatives you considered

Having some flags would also do the trick for me though it seems like "learning about the flag and using it" is its own little set of weirdness

[godlygeek]

You can request that the output file be overwritten by providing a FileDestination constructed with overwrite=True. Does that meet your needs?

[rtpg]

➜ memray run -o out.bin format_results.py
Writing profile results into out.bin
Could not create output file out.bin: File exists

^ this sort of stuff doesn't work still, for non-programmatic use

➜ memray flamegraph -o report.html out.bin
File already exists, will not overwrite: report.html

similarly for this command.

I really do feel like the default should be to overwrite. I have seen very few file write tools that don't apply this logic in general, so I don't think it would surprise people.

The existing behavior creates this extra step that you have to do on multiple runs, but it's extremely common to be running these kinds of commands over many iterations. It's profiling after all

[godlygeek]

Both memray run and memray flamegraph take a -f / --force argument to tell Memray to overwrite the output file even if it already exists. Perhaps we should just update the messages to mention that flag...