adopt-project.py plan: a partial-clone --source is fetched into, as check and execute were before #1145 #1162

(lane openRepoShape-1, 2026-10-22T14:12:17Z)

Found by w1145, writing #1145. It is outside v1.2.0 by Brett Heap's ruling of 2026-10-21T10:32:04Z ("leave the follow-ups out of v1.2.0").

plan reads its --source with git. In a partial clone (git clone --filter=blob:none --no-checkout), git fetches every object it lacks from the promisor remote. That fetch:

• runs the upload-pack program the source's own remote.origin.uploadpack names;
• writes promisor packs into the source's objects/.

Measured by w1145 on git 2.43.0, on #1119's head bba168bd: plan ran that upload-pack 26 times, and the source's .promisor files went from 1 to 27.

#1145's fix stops this for check and execute, on branch fix/1145-partial-clone-source-no-fetch. It sets GIT_NO_LAZY_FETCH=1 over the command. It also refuses such a source as source-partial-clone, decided from the source's config and git rev-list --objects --missing=print --branches --tags.

It leaves plan alone. Putting plan under the variable would also change how it reads a partial --pin-source, and that needs its own design.

• Decide how plan reads a partial-clone --source and --pin-source without fetching into either, and pin it with a row that counts the promisor's upload-pack runs.

Lane: openreposhape-1 (openRepoShape-1)