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[perf-scan] 2026-10-10 -- performance opportunities found

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
62/100
Issue type
Refactor
Clarity
Mostly clear
Activity status
Active
Tech stack
git, python
Domain
cli, devtools

Research direction

Start with the per-package loop in src/apm_cli/commands/uninstall/engine.py around lines 633-671, where packages_to_remove is tested with a list membership check; add a companion set of seen keys and test against it. For the second finding, read the four git config calls in src/apm_cli/deps/bare_cache.py around lines 665-680 and batch them into fewer subprocess spawns. Done means the membership check is set-based and the LFS keys are written with fewer spawns, with existing tests still passing.

Written by the indexing model from the issue text.

Description

type/automation type/performance

Performance Scan - 2026-10-10

Automated scan of src/apm_cli/ for algorithmic performance anti-patterns.
2 finding(s) identified (both low priority).

Findings
[B] Linear scan inside a loop -- src/apm_cli/commands/uninstall/engine.py:633-671
  • Current: O(n*m) -- if matched_dep not in packages_to_remove is a list membership test inside the per-package loop, followed by append.
  • Proposed: O(n) with a companion set of seen keys.
  • Fix: Keep a seen_removals set alongside packages_to_remove and test membership against the set (low priority: n is the number of CLI-specified packages, typically small).
[F] Sequential independent subprocess calls -- src/apm_cli/deps/bare_cache.py:665-680
  • Current: 4 sequential git config subprocess spawns (filter.lfs.smudge/clean/process/required) per consumer checkout, each with its own process start cost.
  • Proposed: 1 spawn, or none.
  • Fix: Write the four LFS-disable keys in a single call (e.g. git -c options on subsequent commands, or one git config --file batch / direct config file write) instead of looping one subprocess per key. Cost scales per package checkout, so total cost is 4x spawns * package count.
Scan coverage
  • src/apm_cli/ (488 files scanned)
  • Patterns checked: A (quadratic loops), B (linear scan in loop),
    C (unconditional expensive ops), D (redundant config parsing),
    E (heavy top-level imports), F (sequential independent I/O)
  • Note: the sequential git fetch then checkout in github_downloader.py:1352 is data-dependent and was not flagged.

Generated by Daily Performance Scanner · copilot · auto · 19 AIC · ⌖ 0.552 AIC · ⊞ 11.1K · ◷

  • expires on Oct 17, 2026, 1:41 AM UTC
Dominant language
Python
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Forks
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Avg merge
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Merged PRs (30d)
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