A dependency can be marked as deprecated - this means that the intention is to remove it over time, but it is still allowed. tach check will not error on deprecated dependencies, but it will surface each import that uses the deprecated dependency.

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Example

Given modules called ‘core’ and ‘parsing’:

# tach.toml
[[modules]]
path = "parsing"
depends_on = [
    { path = "core", deprecated = true }
]

[[modules]]
path = "core"
depends_on = []

Then, in parsing.py:

from core.main import get_data # we want to remove this!

get_data()

This import won’t fail tach check, instead you’ll see:

‼️ parsing.py[L1]: Import 'core.get_data' is deprecated. 'parsing' should not depend on 'core'.
✅ All module dependencies validated!

Note that we still see that all module dependencies are valid! To fail on the dependency, simply remove it from the depends_on key.

Strict Modetach-ignore