fix(affected): parse multi-line, side-effect, and re-export imports (closes #189)

[Wolfvin]

Closes #189

Root Cause (verified)

PR #184 fixed the workspace-as-first-arg heuristic in commands/affected.py so the existing ts_workspace fixture (single-line import { x } from './y') returned affected_count > 0. But get_affected_files still returned affected_count: 0 for three common real-world TS/JS import shapes, because _parse_js_imports silently skipped them — leaving reverse_graph incomplete so BFS had no edges to traverse.

Investigation followed the three steps from issue #189:

1. all_known_files from _build_import_graph — for a workspace where login.ts uses a multi-line import, auth/google-auth-cache.ts was NOT in all_known_files at all (it had no imports itself, and the parser missed the inbound import in login.ts). This is the literal "keys don't match input path" symptom.
2. cf_rel — normalized correctly to auth/google-auth-cache.ts; matched a real file at workspace/cf_rel, so it was added to resolved_changed. BFS started (visited_total: 1) but had no outbound edges to walk.
3. _parse_js_imports regex — confirmed three blind spots (details below).

Three Parser Bugs Fixed

1. Multi-line imports — import {\n foo,\n} from './bar'

The ES import regex used .*? which does not cross newlines. Any import statement split across lines (Prettier default, ESLint multi-line rule, common in real TS codebases) was silently skipped.

Fix: Replace .*? with [\s\S]*? to match across newlines.

2. Side-effect imports — import './polyfills' (no from clause)

The ES import regex required from, so side-effect imports were silently skipped even though they create a real dependency edge (the importing module depends on the side-effect module).

Fix: Add a dedicated import\s+["']...["'] regex. It is disjoint from the from form (requires a quote immediately after import+whitespace), so order does not matter.

3. Re-exports — export { x } from './bar', export * from './bar', export type { Foo } from './bar'

The parser only looked for import, never export ... from. Barrel files (e.g. auth/index.ts re-exporting from auth/core.ts) were invisible to the reverse graph, so changing core.ts would not flag index.ts or any of its consumers as affected.

Fix: Add export\s+[\s\S]*?from\s+["']...["'] regex (with multi-line support).

Why this caused "BFS never starts"

When the parser misses an import, reverse_graph loses an edge. If the changed file's only inbound edge was the missed import:

• The changed file is NOT in all_known_files (it has no imports itself, and the missed import means no inbound edge).
• Wait — actually, the changed file DOES resolve via the os.path.isfile(workspace/cf_rel) fallback, so it lands in resolved_changed.
• BFS starts (visited_total: 1) but reverse_graph.get(changed_file, set()) is empty, so there are no edges to walk.
• affected_count stays at 0.

Net effect for the user: codelens affected <ws> auth/google-auth-cache.ts returns affected_count: 0 and unresolved: [], even though auth/login.ts clearly imports from google-auth-cache.ts. This matches the issue title "BFS never starts".

Tests

5 new tests in TestIssue189ImportParserPatterns:

Test	Bug exposed	Pre-fix	Post-fix
test_multiline_import_resolves_and_bfs_finds_dependents	Multi-line import {\n foo\n} from './bar'	FAIL	PASS
test_side_effect_import_resolves_and_bfs_finds_dependents	import './polyfills' (no from)	FAIL	PASS
test_reexport_creates_dependency_edge	export { x } from './core'	FAIL	PASS
test_multiline_include_source_returns_all_dependents	Multi-line + --include-source	FAIL	PASS
test_existing_ts_workspace_fixture_still_finds_affected	DoD sanity check (existing fixture)	PASS	PASS

All 4 bug-exposing tests fail on the pre-fix code (verified via git stash) and pass after the fix. The 5th (DoD sanity check) passes both before and after — it is the explicit Definition-of-Done assertion from issue #189.

Regression

• tests/test_affected_command.py: 63 passed (58 existing + 5 new)
• tests/test_command_registry.py + test_command_count.py + test_doctor.py: 44 passed
• tests/test_js_backend_parser.py + test_js_frontend_parser.py + test_formatters.py + test_formatters_base.py + test_orient.py: 151 passed, 5 skipped
• No new failures. test_cli.py::TestArgparseFormatConflictRegression::test_scan_with_format_long_does_not_crash times out on codelens scan . — verified pre-existing on main (60s timeout, unrelated to this PR).

Definition of Done (issue #189)

• codelens affected <ts-workspace> auth/google-auth-cache.ts returns affected_count > 0 for a workspace where other files import from that file
• unresolved[] is empty when input file exists and is imported by other files
• Use existing ts_workspace fixture in tests/test_affected_command.py (from PR fix(affected): resolve TypeScript workspaces + path normalization (closes #176) #184) and assert affected_count >= 1

Sebelum → Sesudah

Sebelum (CodeLens main HEAD = ab0d789, with multi-line import in fixture):

• _build_import_graph keys: ['auth/login.ts', 'tests/login.test.ts'] — auth/google-auth-cache.ts is MISSING
• affected_count: 0, visited_total: 1

Sesudah (this PR):

• _build_import_graph keys: ['auth/google-auth-cache.ts', 'auth/login.ts', 'tests/login.test.ts']
• affected_count: 1, visited_total: 3, affected: ['tests/login.test.ts']

Findings

None outside scope.

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[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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