allow duplicates of the same version of the same package

[raylu]

we have multiple requirements.txt files with the same package at the same version (thanks to pip-sync -c requirements1.txt requirements2.in)

$ uv pip sync <(echo packaging==23.1) <(echo packaging==23.1)
error: Failed to determine installation plan
  Caused by: Detected duplicate package in requirements: packaging

I think the check here is too strict

uv/crates/uv-installer/src/plan.rs

Lines 125 to 130 in 4e0b6f8

	// If we see the same requirement twice, then we have a conflict.
	if !seen.insert(requirement.name.clone()) {
	bail!(
	"Detected duplicate package in requirements: {}",
	requirement.name
	);

[ericbn]

pip-tools works as expected:

$ pip-sync <(echo packaging==23.1) <(echo packaging==23.1)
...
Installing collected packages: packaging
Successfully installed packaging-23.1

pip-tools will only fail if there are incompatible requirements found:

$ pip-sync <(echo packaging==23.1) <(echo packaging==23.2)
Incompatible requirements found: packaging==23.2 (from -r /dev/fd/12 (line 1)) and packaging==23.1 (from -r /dev/fd/11 (line 1))

I'd like to see both behaviors in uv too.

[charliermarsh]

I think this makes sense, though I'm not sure what should happen if the requirements overlap? E.g., packaging==23.2 and packaging<=24 or something.

[ericbn]

pip-sync seems to work only when the duplicated requirements are exactly the same, otherwise it will fail with Incompatible requirements found. I guess it makes sense because it expects pinned versions generated by pip-compile (like ==23.2), not ranges like <=24 or anything else.

$ pip-sync <(echo 'packaging==23.2') <(echo 'packaging<=24')
Incompatible requirements found: packaging<=24 (from -r /dev/fd/12 (line 1)) and packaging==23.2 (from -r /dev/fd/11 (line 1))

[ericbn]

See jazzband/pip-tools#786

[charliermarsh]

Fixed in #1558.