perf: cache file reads and AST parses during discovery pass#2135
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perf: cache file reads and AST parses during discovery pass#2135
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This was referenced May 7, 2026
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Moves path-based checks (test file detection, ignore paths, submodule paths, site-packages, outside module-root) to run BEFORE read_text() is called in get_all_files_and_functions() and get_functions_within_lines(). This avoids unnecessary file I/O for files that would be discarded by filter_functions() anyway. Also fixes pre-existing mypy error in _find_all_functions_via_language_support where discover_functions was called with wrong argument order. Signature changes (backward-compatible, all new params are optional): - get_all_files_and_functions: added tests_root, module_root params - get_functions_within_lines: added tests_root, ignore_paths, module_root - get_functions_within_git_diff: added tests_root, ignore_paths, module_root
Introduces a discovery-scoped cache (`discovery_cache()` context manager) that ensures each file is read from disk at most once and parsed into an AST at most once within a single discovery run. Key changes: - `read_file_cached()`: returns cached file content when `discovery_cache()` is active, falls back to normal read otherwise - `parse_ast_cached()`: returns cached `ast.Module` when active - `get_functions_to_optimize()`: wraps its body with `discovery_cache()` - `find_all_functions_in_file()`: uses `read_file_cached` - `inspect_top_level_functions_or_methods()`: uses `parse_ast_cached` - `get_all_replay_test_functions()`: uses `parse_ast_cached` - JS/TS export helpers: use `read_file_cached` - Removed dead code: `_find_all_functions_via_language_support()` (never called, had a type error passing Path as source str) Signature changes: None. All public function signatures are unchanged. The cache is transparent -- when not inside `discovery_cache()`, all functions behave identically to before (direct reads/parses).
The _is_js_ts_function_exported and _is_js_ts_function_exists_but_not_exported helpers each read the file from disk independently, causing up to 2 extra reads per file during get_functions_to_optimize. Add an optional `source` parameter to both functions so callers can pass pre-read content. The main call site now reads the file once and passes it to both helpers. Also fixes pre-existing mypy error in _find_all_functions_via_language_support where discover_functions was called with wrong argument order. Signatures changed: - _is_js_ts_function_exported(file_path, function_name, source=None) - _is_js_ts_function_exists_but_not_exported(file_path, function_name, source=None)
The --file path was calling file.read_text() directly even though find_all_functions_in_file() already primed the discovery cache. Now uses read_file_cached() to hit the cache with zero disk I/O.
The callers BLOB column was fetched and JSON-decoded for every row during FunctionRanker initialization, but the resulting data was never accessed — FunctionRanker.load_function_stats() discards it as `_callers`. This eliminates O(n) JSON parsing at ranking startup. Also fixes all pre-existing mypy errors in this file by declaring pstats.Stats attributes that the type stubs don't expose.
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aseembits93
reviewed
May 8, 2026
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| class TestFiles(BaseModel): | ||
| test_files: list[TestFile] | ||
| _seen_paths: set[Path] = PrivateAttr(default_factory=set) |
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wasn't this merged already?
aseembits93
previously approved these changes
May 8, 2026
perf: read JS/TS files once during discovery export checks
…decode perf: skip unused callers JSON decode in ProfileStats
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Parent PR
#2132 — perf: targeted performance improvements for E2E pipeline hot path
Summary
discovery_cache()context manager that caches file content and parsed ASTs for the duration of a single discovery runread_file_cached()ensures each file is read from disk at most onceparse_ast_cached()ensures each file's AST is parsed at most once_find_all_functions_via_language_support()(never called, had pre-existing type error)Changes
get_functions_to_optimize(): wraps body withdiscovery_cache()find_all_functions_in_file(): usesread_file_cachedinspect_top_level_functions_or_methods(): usesparse_ast_cachedget_all_replay_test_functions(): usesparse_ast_cachedread_file_cachedtests/test_discovery_cache.py(12 tests)Stack
mainperf/discovery-prefilter