orca/docs/reference/windows-process-enumeration.md

Reading the Windows process table

Orca needs three things from the Windows process table: who a PID's parent is (descendant walks and teardown identity), what a process is running (agent recognition), and how much memory/CPU it uses (Resource Manager).

Node cannot answer the first one without native code. That is why seven independent readers existed, each forking powershell.exe to run Get-CimInstance Win32_Process, with a wmic fallback that Windows 11 24H2 has since removed.

Use the native snapshot

src/main/windows/windows-process-table.ts is the only module that may read the table. It wraps a Toolhelp32 snapshot from @vscode/windows-process-tree.

import { readWindowsProcessTable, readWindowsProcessTableFresh } from '../windows/windows-process-table'

• readWindowsProcessTable() — shared TTL cache. Use for anything periodic.
• readWindowsProcessTableFresh() — a snapshot that starts after the call. Use for teardown identity, where a cached row can predate the exit it is being asked about.

Both reject when the table cannot be read. Do not convert that into an empty array. An empty table is a claim that nothing is running, and callers act on that claim by declaring a tree dead or a shell childless. "Unavailable" has to stay distinguishable from "empty" — collapsing the two is how a PTY tree survived its own teardown (#9045).

Measured on Windows 11 with 1050 processes (p50 / p95):

	p50	p95
pid + ppid + name	15.9 ms	17.5 ms
+ memory + command line	30.6 ms	33.7 ms
Get-CimInstance via PowerShell	706 ms	723 ms

Why the package is patched

config/patches/@vscode__windows-process-tree@0.8.0.patch carries two hunks.

1. Spectre mitigation. The upstream binding.gyp requires Spectre-mitigated libraries, which Orca's Windows build agents do not install. node-pty is patched the same way for the same reason.
2. The 1024-process cap. GetRawProcessList stopped after 1024 entries. Measured on a real host with 1051 processes, the module returned exactly 1024 and the querying process was itself among the 27 missing. A truncated snapshot silently hides the descendants a teardown is trying to reap — the exact failure the native path exists to remove.

The typings claim commandLine is truncated at 512 characters. Measured, it is not: the longest observed on a real host was 26,059.

Packaging

The addon is Windows-only, so it follows the same contract as windows-native-registry (asserted by config/scripts/package-electron-runtime-contract.test.mjs):

• an optionalDependency, so a macOS/Linux install tolerates its absence;
• not in pnpm.onlyBuiltDependencies — pnpm installs optional dependencies on every host, and macOS/Linux must never run node-gyp for it;
• listed in the win32 branch of rebuild-native-deps.mjs and ensure-native-runtime.mjs;
• copied into the packaged node_modules for win32 only.

What the snapshot does not provide

CreationDate (process start time) has no equivalent. Anything using a start time to prove a PID has not been recycled — daemon identity, managed-hook ownership, and CPU accounting in the memory collector — still reads it through its own query. Those callers are not migrated.

Start time is a proxy for identity, not identity. The durable answer for the process trees Orca itself spawns is an inherited handle: a job object names the tree Orca created, so no start-time comparison is needed. Those readers should be resolved that way rather than by adding a start time to this module.

Do not adopt getProcessCpuUsage() from the package. It takes both CPU samples inside one call with a blocking Sleep(1000) in the middle, which would hold a libuv threadpool slot for a full second out of the Resource Manager's two-second poll.

Owning a PTY's process tree

src/main/windows/windows-pty-job.ts is the counterpart to reading the table: it answers "is this tree mine, and how do I kill it?" with a handle instead of an inference.

node-pty is patched (config/patches/node-pty@1.1.0.patch) to create a job object per ConPTY and assign the shell to it under CREATE_SUSPENDED, before the shell can spawn anything. Assigning after the fact leaves a window in which a fast child escapes the job.

• terminatePtyJob(proc) — one TerminateJobObject call for the whole tree.
• listPtyJobProcessIds(proc) — the live pids, straight from the kernel.

Measured on Windows 11 against a shell whose grandchild was spawned detached: job membership was [shell, grandchild] and one call killed both. Neither a parent-pid walk nor GetConsoleProcessList sees that grandchild — it leaves the console and reparents, which is what left claude.exe/node.exe/cmd.exe holding worktree directories open (#9045, #10475, #10897).

JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE is set, so the tree is also reaped if the hosting process dies without unwinding. The job belongs to the terminal daemon, not to the app: an app-main crash leaves sessions alive (asserted by .github/workflows/win-crash-survival-e2e.yml), while a daemon death now reaps its shells instead of stranding them (#9195, #10415).

Both functions report unavailable / null rather than a false success when a pty has no job — an outer job without JOB_OBJECT_LIMIT_BREAKAWAY_OK (some EDR and container hosts) can refuse the assignment, and a pty started before this build has none. Callers must fall back, not conclude the tree is gone. That conflation is the original bug.