SEP-1705: Add BaseManager.exists() and convert existence checks

[olucasandrade]

Summary

• Add BaseManager.exists() that emits a short-circuiting SELECT EXISTS (...) with the same filter signature as count(), built through _filter_query.
• Convert the settings-override delete and app-drain finalize existence checks from count(...) to exists().
• Delete TaskHistoryLogManager.exists_for_task and retarget its callers, tests, and docstring cross-references to exists(session, task_history_id=...).

Closes / implements SEP-1705. Related: SEP-1689 / PR #1235 review thread; blocks SEP-1707 only by landing first on the same statement.

Tested

• N/A for primary path — internal manager API refactor with no user-visible UI change
• Optional regression: as admin, DELETE a NOT_OVERRIDABLE settings key with no override row and confirm 409 is unchanged
• Optional: disable an app with in-flight tasks and confirm DISABLING stays until tasks finish

Checklist

• New/modified functions have type hints and rST docstrings
• New tests added for new features or bug fixes
• All tests pass locally (make test) — targeted gate: 264 passed, 1 skipped
• Pre-commit hooks pass (make run-pre-commit) — ran on commit
• Database migrations generated if models changed (make makemigrations) (N/A)
• User-facing changes documented (README, inline help, UI text) (N/A)
• Configuration changes documented with examples (N/A)
• Changelog fragment added under changelog.d/ (N/A — internal-only refactor)

[Copilot]

Pull request overview

This PR introduces a reusable BaseManager.exists() helper for short-circuit existence checks across the FastAPI/SQLModel data layer, then updates a few hot paths (settings override delete, app drain finalize, and task-history log presence checks) to use it instead of count(...) > 0 or a bespoke manager method.

Changes:

• Add BaseManager.exists() implemented via _filter_query(...) and SELECT EXISTS (...).
• Replace select existence checks (count(...) > 0, app drain finalize) with exists(...).
• Remove TaskHistoryLogManager.exists_for_task and retarget call sites/tests to TaskHistoryLogManager.exists(session, task_history_id=...).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
app/core/db/crud.py	Adds BaseManager.exists() using _filter_query and SELECT EXISTS (...).
app/core/settings_override/api/routes.py	Switches override-row existence detection from count(...) > 0 to exists(...).
app/sep/app_drain.py	Converts the “any running tasks for app” check from count(...) to exists(...).
app/tasks/crud.py	Removes TaskHistoryLogManager.exists_for_task and updates related doc references; cleans up now-unused import.
app/tasks/routes.py	Updates task history has_logs computation to use TaskHistoryLogManager.exists(...).
app/tasks/logs/log_reader.py	Switches chunk-presence detection from exists_for_task to exists(...).
tests/app/core/db/test_crud.py	Adds focused unit tests covering BaseManager.exists() behavior and filter handling.
tests/app/tasks/test_routes.py	Updates assertions to use TaskHistoryLogManager.exists(...).
tests/app/tasks/connectivity/test_service.py	Updates log-row existence assertions to exists(...).
tests/app/tasks/connectivity/test_routes.py	Updates log-row existence assertions to exists(...) for HTTP-level tests.

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
app/core/db
crud.py
app/core/settings_override/api
routes.py					1094
app/sep
app_drain.py
inventory.py
app/tasks
crud.py
routes.py					473
app/tasks/logs
log_reader.py
Project Total

This report was generated by python-coverage-comment-action

[olucasandrade]

@copilot resolve the merge conflicts in this pull request

[olucasandrade]

@copilot resolve the merge conflicts in this pull request

[Copilot]

@copilot resolve the merge conflicts in this pull request

Resolved in commit a1a14dc5 by merging latest main into SEP-1705 and fixing the conflict in /home/runner/work/SEP/SEP/app/tasks/crud.py while preserving the BaseManager.exists(...) migration.