PHP: trait whose name collides with an aliased use … as import it composes → unbounded recursion in definitions pass, OOM (SIGKILL)

Version

codebase-memory-mcp 0.8.1

Platform

macOS (Apple Silicon)

Install channel

GitHub release archive / install.sh / install.ps1

Binary variant

ui

What happened, and what did you expect?

A single ~6-line PHP trait drives the indexer into unbounded memory growth during the definitions pass: RSS climbs to ~50% of machine RAM (~18–20 GB on a 36 GB Mac) and the process is OOM-killed (SIGKILL, exit 137).

The trigger is a name collision between a trait and an aliased use … as … import that the trait composes:

trait Auditable …
… that does use \Vendor\Pkg\Auditable as AuditableBase; (imported short name Auditable == trait name)
… and composes it with use AuditableBase;
… and has at least one method with a non-empty body.

The extractor appears to ignore the as alias and resolve the composed trait back to the same-short-name local trait — i.e. it sees trait Auditable composing Auditable (itself), a self-referential trait — then recurses without bound while expanding it to process a method body.

This reproduces with mode: fast, and with CBM_LSP_DISABLED=1 and CBM_DISABLE_LSP_CROSS=1 — so it is not in the LSP resolvers that received depth guards in #720. It is in the definitions pass and needs its own recursion/expansion guard.

Expected: the file indexes instantly (it's 6 lines), as it does the moment any one of the three ingredients is removed.

Reproduction

No proprietary code needed. Create a directory with one file Auditable.php:

<?php
namespace App\Demo;

use Vendor\Pkg\Auditable as AuditableBase;  // aliased import; short name "Auditable" == trait name below

trait Auditable {
    use AuditableBase;                       // composes the aliased trait

    function f() { $x = 1; return $x; }      // any method with a non-empty body
}

Run:

CBM_LSP_DISABLED=1 codebase-memory-mcp cli index_repository \
  '{"repo_path":"/path/to/that/dir","mode":"fast"}'

→ RSS climbs to ~18–20 GB and the process is killed (exit 137). Vendor\Pkg\Auditable does not need to exist — it is an unresolved, pure short-name collision.

All three ingredients are required. Removing any one makes it index instantly at ~0 GB (verified, each run monitored for peak RSS):

Change from the repro above	Result
rename the trait so its name ≠ `Auditable`	✅ OK, ~0 GB
drop `use AuditableBase;` (import present but not composed)	✅ OK, ~0 GB
empty method body `{}` (or no method at all)	✅ OK, ~0 GB
all three present (as above)	❌ OOM, ~20 GB, exit 137

Note: $this is not required — a body of just $x = 1; is enough.

Real-world origin: this is the shape of a trait that wraps the popular owen-it/laravel-auditing package, e.g. use OwenIt\Auditing\Auditable as AuditableBase; inside a local trait Auditable. So it hits real Laravel apps, not just synthetic input.

Logs

From the minimal single-file repro above — it dies right at the start of the definitions pass:

level=info msg=mem.init budget_mb=18432 total_ram_mb=36864
level=info msg=pipeline.discover files=1 elapsed_ms=0
level=info msg=pipeline.route path=full
level=info msg=pass.start pass=structure files=1
level=info msg=pass.done pass=structure nodes=2 edges=1
level=info msg=pass.timing pass=structure elapsed_ms=0
level=info msg=pipeline.mode mode=sequential files=1
level=info msg=pkgmap.scan_repo manifests=0
level=info msg=pkgmap.scan manifests_from_files=0 manifests_from_walk=0 entries=0
level=info msg=pass.start pass=definitions files=1
<no further output — SIGKILL / OOM, exit 137>

Anything else?

Found by bisecting a private Laravel 10 app (~1500 files) that always OOM-killed at indexing, down to this one trait file. laravel/framework @ HEAD (3020 files, 40 784 nodes, 223 117 edges) indexes fine in ~3.7 s at ~1 GB RSS — so this is not a scale/large-repo problem, it's this specific construct.
Independent of mode (fast/moderate), CBM_WORKERS (tried 2 and 14), and LSP flags. Peak RSS is always ~budget_mb (50% of RAM), which is why it OOMs even on an otherwise-idle 36 GB machine.
Likely related: [bug] PHP: framework/core method calls ($storage->load()) become false-positive CALLS edges to same-named project methods — same class as the (fixed) Perl #476 #606 (PHP same-short-name collisions) and py_lsp: py_eval_expr_type infinite recursion — Python missed in 9f981a1 depth-guard fix #720 (LSP depth guard missing for PHP — but note this crash is in the definitions pass, upstream of the LSP resolvers).

Thanks for reducing this to the trait/import-alias collision. Triage: high-priority PHP parser stability and extraction correctness under #390/#592.

The expected behavior is alias-aware trait composition, or at worst an unknown/skipped relation. It must not recurse without bound. The first guard should be a tiny PHP fixture matching this collision and a subprocess/OOM-safe regression so the test runner is not killed by the bug.

Merge pull request #986 from DeusData/fix/php-trait-alias-oom-guards

Regression guards for this landed on main in #986 (merge f7127ee). The underlying fix shipped with #920's trait-alias guards in v0.9.0; the new test reproduces the exact name-collision hang from this report (verified RED against the unguarded code) and now pins it green permanently.

test(php-lsp): regression guards for aliased-trait name-collision OOMs

The v0.9.0 release binary still reproduces this (macOS darwin-arm64, checksum-verified from the release page), so #920's guards don't seem to cover this variant — here the collision is with the alias target's short name, not the alias itself:

namespace App\Models\Traits;

use OwenIt\Auditing\Auditable as AuditableBase; // vendor trait (vendor/ not indexed)

trait Auditable            // short name == short name of the alias *target*
{
    use AuditableBase;     // resolved by short name back into this very trait
    // ...
}

Symptoms on 0.9.0:

parallel.extract.progress stalls at N-4 of N every run; worker RSS grows until the memory-budget kill (SIGKILL at ~16–18 GB with budget_mb=18432). Reproduced 3/3 runs; also reproduces with CBM_INDEX_WORKER_TIMEOUT_S=1800, so it's the budget kill, not the watchdog timeout.
sample of the spinning worker thread:

cbm_extract_file
  cbm_run_php_lsp
    php_lsp_collect_class_fields
      process_class_for_fields
        flatten_trait_into_class   <- hot: cbm_arena_sprintf / cbm_arena_strdup + memmove

Excluding this single 53-line trait file via .cbmignore → the same repo (~1760 files) indexes in 1.7 s / 709 MB RSS.

Found the culprit by diffing CBM_LSP_DEBUG=1 per-module output against the discovered file list. Happy to test a main build or provide more detail if useful.

Reopening based on the detailed post-close v0.9.0 reproduction. The alias target’s short name colliding with the local trait name is a distinct unbounded-recursion variant that the earlier guard did not cover: the definitions pass stalls, memory grows to the worker budget, and excluding the single trait restores a bounded run. This is back in the 0.9.1-rc queue under #390. The RED guard should preserve the exact AuditableBase/Auditable binding shape and prove bounded completion without relying on the worker budget kill.

@KasaharaDefries

Thank you, @KasaharaDefries, for bisecting a whole Laravel app down to one trait, and for the precise sample of flatten_trait_into_class!

We rebuilt your v0.9.0 shape on current main:

use OwenIt\Auditing\Auditable as AuditableBase; inside trait Auditable { use AuditableBase; … };
a model using that trait;
70 more classes using it, to force the parallel path.

It now indexes in about 5 seconds under a 1 GB memory budget, with no runaway growth. Could you confirm on v0.11.0 with the real repo, without the .cbmignore exclusion? If extract progress still stalls at N-4, a fresh sample of the worker would tell us which path is still unbounded.

Thanks for the report! To move this forward we need a bit more so we can reproduce it ourselves:

the codebase-memory-mcp --version you're on
the exact steps or command you ran
a public repo (or a small dummy snippet) that shows the problem — please don't paste proprietary code

Once that's here we'll pick it straight back up. Heads-up: issues left awaiting-reporter are automatically closed after a few weeks of silence, but a comment reopens the door anytime.

This issue has been waiting on more information for 21 days (a version, exact steps, or a public repro), so it's now marked stale. It will not be closed automatically — a maintainer reviews stale issues by hand. Adding a comment with the details clears the label and puts it straight back in the queue. We're happy to pick it back up the moment we can reproduce it.

fix(php): index trait methods by receiver while flattening (DeusData#…

Thank you again for isolating the alias-target collision. Checking back on the September retest request: if you have safely tried a newer build, did the exact trait shape still stall? Please do not repeat an unbounded run just to keep this report open; I have no fresh real-repository confirmation to add.

Thank you again for the report. Any existing safe retest result for the aliased-trait case is welcome; please do not repeat an unbounded OOM run just for this follow-up.

Navigation Menu

Repository navigation

PHP: trait whose name collides with an aliased `use … as` import it composes → unbounded recursion in `definitions` pass, OOM (SIGKILL) #765

Version

Platform

Install channel

Binary variant

What happened, and what did you expect?

Reproduction

Logs

Anything else?

Metadata

Assignees

Labels

Projects

Milestone

Relationships

Development

PHP: trait whose name collides with an aliased use … as import it composes → unbounded recursion in definitions pass, OOM (SIGKILL) #765

Description

Version

Platform

Install channel

Binary variant

What happened, and what did you expect?

Reproduction

Logs

Anything else?

Activity

DeusData commented on Jul 3, 2026

DeusData commented on Jul 9, 2026

KasaharaDefries commented on Jul 16, 2026

DeusData commented on Jul 18, 2026

DeusData commented on Sep 26, 2026

github-actions commented on Sep 26, 2026

github-actions commented on Oct 18, 2026

DeusData commented on Oct 19, 2026

DeusData commented on Oct 25, 2026

Metadata

Metadata

Assignees

Labels

Projects

Milestone

Relationships

Development

Issue actions

PHP: trait whose name collides with an aliased `use … as` import it composes → unbounded recursion in `definitions` pass, OOM (SIGKILL) #765