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Interoperability: DevRepro Doctor and your existing environment managers

DevRepro Doctor is a diagnostic and reproducibility layer, not another package manager or environment manager. It sits across the tools you already use and explains what they do — it never replaces them as the source of truth.

The three modes

Mode What DevRepro does What stays authoritative
Diagnose (default) Read-only probes, findings, snapshots, diffs, drift timelines Your environment manager
Generate (devrepro generate) Drafts config files from detected requirements You, after review
Defer Detects an environment manager and reports its state instead of second-guessing it The manager, explicitly

Per-tool guidance

Nix / Nix Flakes

  • Diagnose: daemon mode, flakes support, trusted-user issues, channel/registry state.
  • Defer: when a flake.lock exists, DevRepro treats the flake as the source of truth for tool versions and only reports whether the machine can use it.
  • Never generates Nix expressions.

devenv

  • Diagnose: version, shell integration, process/service config validation.
  • Defer: devenv.lock pins win over inferred requirements.

Devbox

  • Diagnose: project detection, lock analysis, package-resolution symptoms.
  • Defer: devbox.lock is authoritative.

mise / asdf

  • Diagnose: tool-version policy parsing, active-version mismatch checks.
  • Generate: .mise.toml / .tool-versions drafts from explicit requirements (devrepro generate mise|asdf) — always preview-first, never overwrite without --overwrite.
  • If both a lockfile and a tool-version file exist, the lockfile wins.

direnv

  • Diagnose: .envrc presence/authorization/shell-hook status. Executed shell code is treated cautiously; contents are never printed.

Dev Containers / DevPod

  • Diagnose: spec discovery, local machine compatibility, runtime detection.
  • Generate: devcontainer.json drafts marked generated, review required.

Language managers (pyenv, nvm/fnm/Volta, rbenv, conda, …)

  • Diagnose: which manager owns each toolchain (provenance), version mismatches, PATH shadowing between managers.
  • Defer: the active manager's version selection is reported, not overridden.

Rules of engagement

  1. Read-only by default. Nothing on your machine changes without explicit confirmation, and remediation plans show exact commands before anything runs.
  2. Lockfiles beat manifests beat inference. When sources disagree, DevRepro says so instead of silently picking one.
  3. Generated files require review. Every generator output is previewed with a diff; existing files are never overwritten without --overwrite.
  4. No forced migration. DevRepro never suggests abandoning a working environment manager; it explains conflicts so you can decide.
  5. Privacy holds everywhere. Snapshots shared with teams or fleets are sanitized; secrets are redacted at the source.

Where this stops and something else starts

Application profiling — react-doctor. This tool explains why an application will not build on a given machine. Why it is slow once it does is a different question, answered by attaching to a running process — and attaching a debugger to somebody's process is the furthest thing from read-only in this project. react-doctor does that job well; this one links there rather than competing.

Environment management — Nix, mise, Devbox. They manage environments; this diagnoses them, including theirs. devrepro envmanagers reports what each declares versus what is actually active, and devrepro reproduce --emit nix hands a Nix-shaped team a starting point rather than pretending to be a package manager.