adopt-project.py check: a partial-clone source missing blobs that check reads is fetched into, so check's own reads run the upload-pack its config names and write a promisor pack into the source #1145

(2026-10-21T22:13:19Z, lane openRepoShape-1)

Found by: r1119b's re-check of #1119 (#1083), NIT-D, probe 10. It predates #1119. 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").

check promises never to write into the source. Take a source that is a partial clone (git clone --filter=blob:none --no-checkout) whose HEAD blobs are absent. check's own reads of the source make git fetch the missing blobs from the promisor remote. These are not its throwaway repositories' reads.

• That fetch runs the upload-pack program the source's own config names (remote.origin.uploadpack). A counting wrapper ran 5 times in one check.
• It also writes a promisor pack into the source's objects/pack.

How it was measured:

• r1119b ran it on git 2.43 with check --work-dir. The plan was written first. Then the source was made again as such a clone of a local origin, at the same commit.
• The result was the same on main 823624d9, on adopt-project.py: check asks the split's own clone of the source in the work directory, so a clone this git will not make is adopt-git-unasked before any leg, and _resolved and _answers make their repositories as check's other throwaways do (#1083) #1119's head 9b998936, on main 4ed7c7bf, and on the two merged.
• So adopt-project.py: check asks the split's own clone of the source in the work directory, so a clone this git will not make is adopt-git-unasked before any leg, and _resolved and _answers make their repositories as check's other throwaways do (#1083) #1119's clone, which borrows objects with --shared and checks nothing out, is not the cause.
• The probe is _lane1-scratch/r1119/r2/probe2.py (partial_after_plan), with logs in probes/partial-after-plan-*. Both are on the lane's bench.

Not yet measured:

• A promisor on a network. By reading the code, the same reads would fetch over it, with the credentials of whoever runs check.
• What execute does with the same source.

Two possible fixes:

• Ask the source with lazy fetch off, and make a blob that is then unreadable a finding, or a NOTE that names the partial clone. git 2.43 has no --no-lazy-fetch (measured: unknown option); a later git has it.
• Refuse such a source before anything is read.

Either way, a row should count the promisor's upload-pack runs, and hash the source's objects/ before and after check.

Lane: openreposhape-1 (openRepoShape-1)