Detect path join with hardcoded absolute path

[joshtriplett]

What it does

Detect calls to .join with an absolute path as an argument. This won't do what the user likely expects. join with an absolute path will ignore the left-hand side and just use the absolute path.

For example, root.join("/bin/sh") will return the path "/bin/sh".

In an ideal world, this would also detect calls like root.join(SOME_CONSTANT) where the constant is a hardcoded absolute path, as well, but that may be harder. This would still provide value even if it only detects absolute paths specified directly in the join call.

The lint should explain the behavior of join, and should suggest removing the leading / from the absolute path.

Lint Name

join_absolute_path

Category

correctness

Advantage

Removing the leading / from the user's path will make the join create a path relative to the path given on the left-hand side of the join operation.

Drawbacks

No response

Example

some_path.join("/bin/sh")

Could be written as:

some_path.join("bin/sh")

[anthonygedeon]

@rustbot claim

[xFrednet]

Hey @anthonygedeon, there is already an open PR #10663 to implement the lint. This is just a quick warning to avoid duplicate work :)

[anthonygedeon]

@xFrednet Thanks for letting me know! I'll try to look for another good-first-issue then