fix(telemetry): the CLI never looks where Windows installs spool (backend#2377)

[LukasWodka]

Summary

Closes tracebloc/backend#2377. Part of the backend#1872 telemetry epic.

installerSpoolFiles (internal/cli/telemetry_installer_spool.go) looked for the installer's pre-log fallback spool in $TMPDIR, $HOME and /tmp. The PowerShell installer writes it to $USERPROFILE, else $HOME, else [IO.Path]::GetTempPath() (i.e. TMP/TEMP) — client/scripts/lib/telemetry.ps1, Get-TelemetryFallbackSpool. Windows sets neither TMPDIR nor, usually, HOME, so the search reduced to /tmp, which does not exist there.

Result: Windows pre-log install failures were spooled and never delivered. That is precisely the class the fallback exists for — validate_config and early_data_dir_guard run before there is a log or a data dir, so the fallback file is their only record. The data-dir spool was unaffected: this function already resolves that one through os.UserHomeDir(), which is USERPROFILE on Windows. The glob was fine too — tracebloc-telemetry-* already matches the twin's .jsonl suffix.

Type

Bug fix.

Changes

• installerFallbackDirVars — the candidate variables, named once and documented against both producers' fallback chains (telemetry.sh _telemetry_fallback_dir and telemetry.ps1 Get-TelemetryFallbackSpool), with the residual stated in the code: those producers live in tracebloc/client, so nothing in this repo's CI can prove the list still agrees with them. Review rule until the two repos share a fixture.
• The loop reads that list instead of three inline literals.
• filepath.Clean replaces strings.TrimRight(dir, "/") for dedup, so a trailing separator collapses on Windows too. Two spellings of one directory would forward the same install outcome twice in one batch.

Test plan

Three new tests in internal/cli/telemetry_installer_spool_test.go:

1. TestInstallerSpoolFilesFindsTheFallbackOnEveryHomeVariable — a subtest per variable, each setting only that variable. The five names are written down independently of installerFallbackDirVars, deliberately: a test that feeds the production list back into itself is self-consistent and would plant a typo rather than catch one.
2. TestInstallerFallbackDirVarsAreAllSearched — totality. Catches the opposite failure: a name added to the vocabulary and never wired into the loop.
3. TestInstallerSpoolFilesDedupesATrailingSeparator — guards the filepath.Clean.

Mutation-proved, with the anchor asserted applied each time (the diff was printed per mutation, so an inert mutation could not pass for coverage):

mutation	reddened
drop "USERPROFILE" from the list	…OnEveryHomeVariable/USERPROFILE
revert the loop to the pre-fix {"TMPDIR","HOME"}	/USERPROFILE, /TEMP, /TMP, totality, dedupe
iterate installerFallbackDirVars[:len-1]	/TMP, totality
remove the seen[dir] check	dedupe

Restored and green afterwards.

Ran locally (go1.26.6, darwin/amd64): gofmt -l clean, go vet ./... clean, go build ./..., go test ./... -count=1 → 18 packages ok, 0 FAIL.

Could not run locally: golangci-lint (not installed on this machine — CI's golangci.yml covers it), and the Windows path semantics themselves. filepath.Clean on darwin does not treat \ as a separator, so the Windows half of the dedup change is exercised by construction rather than by execution; the build.yml cross-platform matrix compiles it, and the behavioural fix (searching USERPROFILE/TEMP/TMP at all) is fully covered on any platform.

Checklist

• Targets develop
• Linter and the tests covering the change run, output above
• Full diff read
• No secrets, tokens or customer data
• No CLAUDE.md / BUGBOT.md / runbook statement is made false by this change

🤖 Generated with Claude Code

---

Note

Low Risk
Narrow path-discovery fix for installer telemetry drain, with tests. No auth, ingest, or filtering-logic changes.

Overview
The CLI now finds the installer's pre-log fallback spool on Windows. installerSpoolFiles previously only searched $TMPDIR, $HOME, and /tmp, so Windows writes under $USERPROFILE / $TEMP / $TMP were never drained.

Candidate dirs now come from installerFallbackDirVars (TMPDIR, HOME, USERPROFILE, TEMP, TMP) plus bash's literal /tmp. Dedup uses filepath.Clean so a trailing separator does not send the same install outcome twice.

Tests pin each env var independently, assert every declared name is actually searched, and cover trailing-separator dedup.

^{Reviewed by Cursor Bugbot for commit dd34cba. Bugbot is set up for automated code reviews on this repo. Configure here.}

[saqlainsyed007]

Verified against the code and the producers' chains — clean fix.

The spool search was TMPDIR → HOME → /tmp, but the PowerShell installer writes to USERPROFILE → HOME → TMP/TEMP, and Windows sets neither TMPDIR nor usually HOME — so it reduced to /tmp, which doesn't exist there, and every Windows pre-log install failure was spooled and never collected (exactly the class the fallback exists for: validate_config/early_data_dir_guard run before any log). Adding USERPROFILE/TEMP/TMP closes it, and filepath.Clean (not TrimRight("/")) correctly dedups a trailing separator on both platforms.

The test earns its keep: TestInstallerSpoolFilesFindsTheFallbackOnEveryHomeVariable writes the five var names independently of installerFallbackDirVars, so a typo in the production list can't be mirrored into the test and pass anyway (rule 9); one subtest per var with only that var set makes each assertion about that var, not the environment. The cross-repo residual (producers live in tracebloc/client, kept in step by review until a shared fixture) is stated, not hidden. CI green, no threads. LGTM.