Module DevLog 

Tag-filtered development logging (Trace env var). Must be declared before WindServiceHandlers so the dev_log! macro is available.

DevLog - Tag-filtered development logging

Controlled by Trace environment variable. The same tags work in both Mountain (Rust) and Wind/Sky (TypeScript).

Usage

Trace=vfs,ipc ./Mountain          # only VFS + IPC
Trace=all ./Mountain              # everything
Trace=short ./Mountain            # everything, compressed + deduped
Trace=terminal,exthost ./Mountain # terminal + extension host
./Mountain                               # nothing (only normal log!() output)

Short Mode

Trace=short enables all tags but compresses output:

• Long app-data paths aliased to $APP
• Consecutive duplicate messages counted ((x14) suffix)
• Rust log targets compressed (D::Binary::Main::Entry → Entry)

File sink

When Record=1 (or, in debug builds, Trace is set), every emitted line is mirrored to:

~/Library/Application Support/<bundle>/logs/<YYYYMMDDTHHMMSS>/Mountain.dev.log

The timestamp directory follows Tauri’s tauri-plugin-log format, so the dev log sits next to the plugin’s own log file for the same boot (one directory per process start). Use Record=0 to force- disable even in debug. File writes are flushed per line so tail -f shows live output.

Tags (38 granular tags across all Elements)

Tag	Scope
vfs	File stat, read, write, readdir, mkdir, delete, copy
ipc	IPC routing: invoke dispatch, channel calls
config	Configuration get/set, env paths, workbench config
lifecycle	Startup, shutdown, phases, window events
storage	Storage get/set/delete, items, optimize
folder	Folder picker, workspace navigation
exthost	Extension host: create, start, kill, exit info
extensions	Extension scanning, activation, management
terminal	Terminal/PTY: create, sendText, profiles, shell
search	Search: findFiles, findInFiles
themes	Theme: list, get active, set
window	Window: focus, maximize, minimize, fullscreen
nativehost	OS integration: process, devtools, shell
clipboard	Clipboard: read/write text, buffer, image
commands	Command registry: execute, getAll
model	Text model: open, close, get, updateContent
output	Output channels: create, append, show
notification	Notifications: show, progress
progress	Progress: begin, end, report
quickinput	Quick input: showQuickPick, showInputBox
workingcopy	Working copy: dirty state
workspaces	Workspace: folders, recent, enter
keybinding	Keybindings: add, remove, lookup
label	Label service: getBase, getUri
history	Navigation history: push, goBack, goForward
decorations	Decorations: get, set, clear
textfile	Text file operations: read, write, save
update	Update service: check, download, apply
encryption	Encryption: encrypt, decrypt
menubar	Menubar updates
url	URL handler: registerExternalUriOpener
grpc	gRPC/Vine: server, client, connections
cocoon	Cocoon sidecar: spawn, health, handshake
bootstrap	Effect-TS bootstrap stages
preload	Preload: globals, polyfills, ipcRenderer

Batch 1 diagnostic tags (Row 1-3 fix surfaces)

Narrow tags added to isolate the architectural gaps surfaced by the analysis table. Enable selectively with e.g. Trace=notif-drop,git,tree-view to filter to just the subsystem under investigation.

Tag	Scope
notif-drop	Notifications that hit the _ => {} default arm (dropped silently)
provider-register	Accepted register_*_provider notifications + handle + extension id
channel-stub	Wind/Output TauriMainProcessService.call stub-hit vs route vs miss
git	localGit channel, GitExec RPC, SCM provider group updates
tree-view	tree.register, GetTreeChildren, sky://tree-view/create emit

Batch 2 diagnostic tags

Tag	Scope
sky-emit	Mountain → Wind/Sky sky:// emits: channel, payload bytes, ok/fail
config-prime	Configuration cache: manifest pre-populate, subtree synthesise
ext-activate	Per-extension activate: start, outcome (ok/fail/skip), duration
breaker	Cocoon MountainClientService circuit-breaker state transitions
cel-dispatch	SkyBridge cel:* CustomEvent dispatch + consumer-present flag

Batch 3 diagnostic tags

Added 2026-04-23 late after Batches 3-6 wired notification handlers, git channel, tree-view dataProvider forwarding, and medium stub backfill. These tags catch the subsystems the new traffic passes through so regressions surface as silent tag counts going to zero (or, for tauri-invoke, per-invoke latency spikes).

Tag	Scope
ext-scan	Extension scanner decisions: is-builtin vs user, skip reasons, counts
scheme-assets	vscode-file:// / vscode-resource:// request routing, MIME, bytes
preload-shim	Wind Preload.ts globals wiring, VS Code ipcRenderer polyfill install
tauri-invoke	Per-invoke method + duration (augments ipc’s paired invoke/done lines)
bootstrap-stage	Cocoon Effect/Bootstrap.ts stage timings (start/ok/fail per phase)

Batch 4 diagnostic tags

Added 2026-04-24 alongside the workspace.fs tier-split refactor. Cocoon’s WorkspaceNamespace/FileSystemRoute.ts now chooses between Tier A (node:fs/promises in-process) and Tier C (Mountain FileSystem.* gRPC) per URI scheme + custom-provider claim. The tag surfaces every decision so empirical workload profiling confirms the split is paying off - grep 'route=native' / grep 'route=mountain' buckets per run. Emitted from Cocoon stdout, picked up by Mountain’s [DEV:COCOON] stdout tail with the standard [DEV:FS-ROUTE] prefix.

Tag	Scope
fs-route	workspace.fs.* + openTextDocument native-vs-mountain routing
cmd-route	commands.executeCommand local-vs-mountain routing
dual-track	Mountain-first / Node-fallback progressive Rust migration dispatches

dual-track tag usage pattern

Every Cocoon shim that wraps TryMountainThenNode logs one of four decisions per dispatch:

• route=mountain Mountain handled it (Rust code path served the call)
• route=node-fallback Build-time manifest says no Mountain handler (or runtime confirmed “Unknown method: X”); Cocoon’s Node / stock-VS-Code implementation served it
• route=unavailable Tier-4: no tier covers the method. Extension receives typed NotImplementedError; build surfaces this as a feature-gap
• route=error Tier failed unexpectedly; error propagated

Grep the stream to see which vscode.* methods Mountain doesn’t yet cover - that set IS the Rust migration TODO list. A method moves from node-fallback to mountain automatically the moment Mountain lands its Rust handler AND the manifest is regenerated. route=unavailable rows are the apologise-to-user list.

A single [DEV:DUAL-TRACK] manifest mountain=N stockLift=M bespoke=K line prints at Cocoon boot with the build-time tier coverage generated by Maintain/Script/GenerateRouteManifest.sh.

Structs

DedupState

Constants

BENIGN_ENOENT_SUBSTRINGS 🔒

SHORT_MODE_MUTED_TAGS 🔒

Tags explicitly muted by short mode. These are the per-call firehose tags (receive / dispatch / verify / forward banners) that add no diagnostic signal beyond the aggregate IPC round-trip timing already present in the ipc / grpc summary lines. Listing them here keeps short usable as a “quiet but informative” default - the failure path for each of these still logs a specific error tag (grpc for gRPC errors, ipc for IPC failures, etc.).

Statics

APP_DATA_PREFIX 🔒

DEBUG_ONCE_KEYS 🔒

DEDUP

ENABLED_TAGS 🔒

LOG_FILE 🔒

OTLP_AVAILABLE 🔒

OTLP_TRACE_ID 🔒

SHORT_MODE 🔒

Functions

AliasPath

Replace the long app-data path with $APP in a string.

AppDataPrefix

Get the app-data path prefix for aliasing (cached).

BinarySignature 🔒

Produce an identity signature for THIS running binary derived from CARGO_PKG_NAME (which Maintain sets to the long PascalCase product name before cargo build). Each profile produces a distinct signature

DebugOnce

Emit the line exactly once per process, keyed on the supplied key. Later calls with the same key are silently dropped. The file sink still captures the very first occurrence so the probe is documented.

DebugOnceKeys 🔒

DetectAppDataPrefix 🔒

EmitOTLPSpan

Emit an OTLP span to the local collector (Jaeger at 127.0.0.1:4318). Fire-and-forget on a background thread. Stops trying after first failure.

EnabledTags 🔒

FileSinkEnabled 🔒

Decide whether the file sink should be active. Returns the final flag once per process; subsequent calls are cached.

FlushDedup

Flush the dedup buffer - prints the pending count if > 1.

FormatTimestamp 🔒

GetTraceId 🔒

InitEager

Force the file sink to initialize before any dev_log! has run.

InitFileSink 🔒

Initialise the file sink on first call. Silently falls through to a disabled sink if the directory or file can’t be created - the caller must never panic because of a log-file failure.

IsBenignEnoent

Return true when the given path is a known-optional probe whose absence is never an error condition. Used to downgrade stat ENOENT spam.

IsEnabled

Check if a tag is enabled.

IsShort

Whether Trace=short is active.

NowNano

ResolveLogDirectory 🔒

Resolve the log directory for this session: ~/Library/Application Support//logs//

SessionTimestamp

Session timestamp in local time, cached once per process. MUST match whatever WindServiceHandlers.rs::"nativeHost:getEnvironmentPaths" builds, because VS Code’s file service writes window1/output/*.log into the directory that handler returns - if DevLog and VS Code use different timezones, Mountain.dev.log and the window1/ subtree land in two sibling directories 2-3 hours apart, which makes every post-mortem investigation start with “which folder has the real log?”. Picking chrono::Local::now() matches the VS Code convention (Tauri’s tauri-plugin-log also writes local-time YYYYMMDDTHHMMSS).

SplitPascalCaseIntoWords 🔒

Split a PascalCase / UPPERCASE string into lowercase component words, matching the tokenisation Maintain’s Build/Process.rs applies when it stamps the Tauri identifier. Example: ElectronProfile → ["electron", "profile"]; 22NodeVersion → ["22", "node", "version"]. Empty segments are filtered out.

WriteToFile

Append a single formatted line to the session’s log file if the file sink is active. Swallows every error - dev_log must never crash.

rand_u64 🔒