via lines often result in git conflict

[graingert]

What's the problem this feature will solve?

currently when adding and removing packages in multiple github PRs the # via line will conflict

Describe the solution you'd like

put each # via on a new line:

six==1.12.0 \
    --hash=sha256:3350809f0555b11f552448330d0b52d5f24c91a322ea4a15ef22629740f3761c \
    --hash=sha256:d16a0141ec1a18405cd4ce8b4613101da75da0e9a7aec5bdd4fa804d0e0eba73 \
    # via automat, bcrypt, cryptography, ecdsa, format-cef, grpcio, patchy, pathlib, prompt-toolkit, protobuf, pyhamcrest

instead use:

six==1.12.0 \
    --hash=sha256:3350809f0555b11f552448330d0b52d5f24c91a322ea4a15ef22629740f3761c \
    --hash=sha256:d16a0141ec1a18405cd4ce8b4613101da75da0e9a7aec5bdd4fa804d0e0eba73 \
    # via automat
    #   , bcrypt
    #   , cryptography
    #   , ecdsa
    #   , format-cef
    #   , grpcio
    #   , patchy
    #   , pathlib
    #   , prompt-toolkit
    #   , protobuf
    #   , pyhamcrest

Alternative Solutions

Additional context

[graingert]

also the missing trailing slash on deps without # via lines also conflict - this would be fixed with #881

[jdufresne]

I've been running into the same frustration.

This is especially noticeable on Django projects that include many Django 3rd party libraries. The Django "via" line can easily extend beyond column 200.

Proposed fix in #1237. If there is a single annotation, then it is rendered on one line, otherwise, one per line.

[graingert]

also the missing trailing slash on deps without # via lines also conflict - this would be fixed with #881

@jdufresne it looks like there's now always a missing trailing slash - this increases the chance of a merge conflict

[jdufresne]

The final trailing slash doesn't make sense. The slash indicates "escape this newline, to continue the statement".

I agree that it is unfortunate that this can lead to merge conflicts, but it is still wrong placement, IMO.

For example, the text:

six==1.12.0 \
    --hash=sha256:3350809f0555b11f552448330d0b52d5f24c91a322ea4a15ef22629740f3761c \
    --hash=sha256:d16a0141ec1a18405cd4ce8b4613101da75da0e9a7aec5bdd4fa804d0e0eba73
    # via
    #   bcrypt
    #   cryptography

After expanding the newline escapes, should expand to:

six==1.12.0 --hash=sha256:3350809f0555b11f552448330d0b52d5f24c91a322ea4a15ef22629740f3761c --hash=sha256:d16a0141ec1a18405cd4ce8b4613101da75da0e9a7aec5bdd4fa804d0e0eba73
    # via
    #   bcrypt
    #   cryptography

Notice the first comment is on the next line.

It should not expand to:

six==1.12.0 --hash=sha256:3350809f0555b11f552448330d0b52d5f24c91a322ea4a15ef22629740f3761c --hash=sha256:d16a0141ec1a18405cd4ce8b4613101da75da0e9a7aec5bdd4fa804d0e0eba73  # via
    #   bcrypt
    #   cryptography

The final newline happens to work as the next line is a comment, but if someone disabled annotations (--no-annotate), the next line would no longer be a comment.