the-other-dude/.planning/phases/05-diff-engine/05-02-SUMMARY.md

phase, plan, subsystem, tags, requires, provides, affects, tech-stack, key-files, key-decisions, patterns-established, requirements-completed, duration, completed

phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	requirements-completed	duration	completed
05-diff-engine	02	api	parser routeros structured-changes tdd	phase plan provides 05-diff-engine 01 generate_and_store_diff() and router_config_diffs table	parse_diff_changes() for extracting structured component changes from unified diffs router_config_changes rows linked to diff_id for timeline UI	07-timeline-api	added patterns tdd-red-green best-effort-secondary-operation	created modified backend/app/services/config_change_parser.py backend/tests/test_config_change_parser.py backend/app/services/config_diff_service.py backend/tests/test_config_diff_service.py	Change parser is pure function (no DB/IO) for easy testing; DB writes happen in diff service RETURNING id added to diff INSERT to capture diff_id for linking changes Change parser errors are best-effort: diff is always stored, only changes are lost on parser failure	RouterOS path to component: strip leading /, replace spaces with / (e.g., /ip firewall filter -> ip/firewall/filter) Fallback component system/general for diffs without RouterOS path headers	DIFF-03 DIFF-04	2min	2026-03-13

Phase 5 Plan 2: Structured Change Parser Summary

RouterOS diff change parser extracting component names, human-readable summaries, and raw lines from unified diffs with best-effort DB storage

Performance

• Duration: 2 min
• Started: 2026-03-13T03:34:48Z
• Completed: 2026-03-13T03:37:14Z
• Tasks: 2
• Files modified: 4

Accomplishments

• Pure-function change parser extracts component, summary, raw_line from RouterOS unified diffs
• RouterOS path detection converts section headers to component format (ip/firewall/filter)
• Human-readable summaries: Added/Removed/Modified N rules per component
• Diff service wired to call parser after INSERT and store results in router_config_changes
• Parser failures are best-effort: diff always stored, changes lost only on parser error

Task Commits

Each task was committed atomically:

1. Task 1: Change parser TDD RED - 7fddf35 (test)
2. Task 1: Change parser TDD GREEN - b167831 (feat)
3. Task 2: Wire parser into diff service - 122b591 (feat)

TDD task had separate RED and GREEN commits

Files Created/Modified

• backend/app/services/config_change_parser.py - Pure parser: parse_diff_changes() with path detection, summary generation, raw line capture
• backend/tests/test_config_change_parser.py - 6 unit tests covering additions, multi-section, removals, modifications, fallback, raw_line
• backend/app/services/config_diff_service.py - Added RETURNING id, parse_diff_changes integration, change INSERT loop
• backend/tests/test_config_diff_service.py - Updated existing tests for RETURNING id, added 2 tests for change storage and parser error resilience

Decisions Made

• Change parser is a pure function (no DB/IO) for straightforward unit testing; DB writes are the diff service's responsibility
• RETURNING id added to diff INSERT SQL to get diff_id without separate query
• Change parser errors caught by separate try/except so diff is always committed first

Deviations from Plan

Auto-fixed Issues

1. [Rule 1 - Bug] Updated existing diff service tests for RETURNING id and parse_diff_changes integration

• Found during: Task 2
• Issue: Existing tests expected 3 execute calls without scalar_one on INSERT result; new RETURNING id and parse_diff_changes call changed the interaction pattern
• Fix: Added scalar_one mock to INSERT result, patched parse_diff_changes to return empty list in existing tests to isolate behavior
• Files modified: backend/tests/test_config_diff_service.py
• Committed in: 122b591

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Total deviations: 1 auto-fixed (1 bug) Impact on plan: Necessary test update for API change. No scope creep.

Issues Encountered

None

User Setup Required

None

Next Phase Readiness

• router_config_changes table populated with structured changes for every non-empty diff
• Changes linked to diff_id, device_id, tenant_id for timeline queries
• Ready for timeline API (Phase 7) to query changes per device

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Phase: 05-diff-engine Completed: 2026-03-13