kandev/docs/plans/go-dev-launcher/task-01-dev-paths.md

id, title, status, wave, depends_on, plan, spec

id	title	status	wave	depends_on	plan	spec
01-dev-paths	Dev paths, repo root, and dev backend env	done	1		plan.md	../../specs/platform/requirements/go-dev-launcher.md

Task 01: Dev paths, repo root, and dev backend env

Port the pure path/env logic from apps/cli/src/{constants,kandev-env,dev}.ts into Go. No process spawning in this task.

Acceptance

• findRepoRoot(startDir) returns the nearest ancestor containing both apps/backend and apps/web, also handling a start directory that is .../apps; it returns an error (not a fallback path) when no such ancestor exists.
• resolveDevBackendEnv(repoRoot) reproduces the three-way rule in apps/cli/src/dev.ts:125-167: inside a task workspace it sets KANDEV_HOME_DIR=<repoRoot>/.kandev-dev and clears KANDEV_DATABASE_PATH; outside one an explicit KANDEV_DATABASE_PATH wins; otherwise it uses the .kandev-dev default. KANDEV_DEBUG_DEV_MODE=true is set in all three branches, and the reported display DB path matches what the backend will derive.
• isInsideKandevTask(repoRoot) is true when KANDEV_TASK_ID is set, or when repoRoot is under <userHome>/.kandev/tasks/.

Verification

Use TDD. Add apps/backend/internal/launcher/devpaths_test.go covering each branch with t.TempDir()-rooted fake trees (never the real filesystem root — see apps/backend/CLAUDE.md, "Path/security tests"), then:

cd apps/backend && go test ./internal/launcher/ -run 'TestFindRepoRoot|TestResolveDevBackendEnv|TestIsInsideKandevTask' -race

Files

• apps/backend/internal/launcher/devpaths.go (new)
• apps/backend/internal/launcher/devpaths_test.go (new)
• apps/backend/internal/launcher/constants.go — add devKandevDotdir = ".kandev-dev", devKandevHome(repoRoot), kandevTasksDir(), and healthTimeoutDevMS = 600000 alongside the existing healthTimeoutReleaseMS.

Inputs

• apps/cli/src/dev.ts:112-167 — resolveDevBackendEnv, including the comments explaining why dev always roots under .kandev-dev and why a task-workspace KANDEV_DATABASE_PATH is treated as leaked. Carry that reasoning across.
• apps/cli/src/kandev-env.ts — note its caveat that the path-prefix check is a defensive secondary signal, is case-sensitive, and does not resolve symlinks; KANDEV_TASK_ID remains the primary guarantee.
• apps/cli/src/constants.ts:47-56 — DEV_KANDEV_DOTDIR, devKandevHome.
• Existing apps/backend/internal/launcher/constants.go for the resolve-* naming style.

Risks

• Do not change resolveHomeDir / resolveDataDir / resolveDatabasePath; start, run, and service all depend on their current env-reading behavior.
• os.UserHomeDir() can fail; mirror the existing .kandev relative fallback rather than panicking.