[CT-107] Install streaming, memory, backpressure, and process-count ratchets #54

ADR-THINK-001 · Delivery plan · Complete issue catalog

Milestone: ADR-THINK-001 P1 — Evidence substrate

Feature: F1.2 — Windowed evidence admission

Outcome

Every growing evidence-substrate path is mechanically classified and fails CI when memory, queue, child-process, cancellation, or barrier bounds regress.

User stories

• As a performance maintainer, I want same-runner resource ceilings in CI, so that a fast local machine cannot hide O(history) processes or residency.
• As a feature author, I want an explicit streaming/barrier classification for each growing operation, so that collecting unbounded input becomes a visible design violation.

Deliverables

• Operation-class registry: streaming, bounded barrier, or forbidden global barrier.
• RSS, heap, queue-depth, in-flight element, and Git-process measurement harness.
• Cancellation and stalled-branch tee/demux conformance tests.
• Versioned absolute and base/head performance policy evidence.

Acceptance criteria

• Every evidence-substrate operation has one registered class and bound.
• Process ceilings scale by stream session or AdmissionWindow rather than logical item count.
• RSS slopes remain approximately flat across geometrically growing fixture sizes.
• Cancelling a consumer closes producers, child processes, and branch queues.

Test plan

Contract and unit

• Registry tests reject missing classes, invalid bounds, and unregistered growing operations.

Integration and acceptance

• Same-runner base/head benchmarks cover cold/warm capture, exact read, windows, and recovery.

Failure and recovery

• Mutants add collect(), process-per-item, unbounded queues, and ignored cancellation; every mutant must fail.

Resource and performance

• Reference-runner evidence gates RSS slope, queue depth, in-flight elements, child count, and wall-time regression.

Build-time resources

• exclusive: Only one active slice may mutate or lease the named resource.
• partitioned: Concurrent writes are lawful only in disjoint partitions named by each slice.
• shared: Concurrent read-only use is lawful; this slice does not mutate the resource.

Dependencies

• Blocked by #52 — CT-105
• Blocked by #53 — CT-106
• External dependency: perf: batch patch-chain and git-cas object reads git-stunts/git-warp#847

ADR traceability

• Implementation gates: G1
• Constitutional invariants: I13, I14
• ADR acceptance criteria: AC21, AC22

Non-goals

• Do not bless a stream that materializes its full source before first output.
• Do not ban declared bounded atomic barriers.