[amar-python]

Closes #174.

What this changes

build/config.local.env (written by build/setup.sh and scripts/provision_full_test_env.sh) and the concrete build/environments/env_<env>.sql files hold real credentials. Both are gitignored — but .gitignore does not filter the Docker build context, so docker build . from a configured checkout copied them into an image layer. Layers are immutable and cached indefinitely; once such a layer is pushed to a registry, rotating the leaked password is the only remediation, and only if somebody notices.

Both fixes from the 3 Nov decision, in one PR, defence in depth:

• (a) .dockerignore — lists **/config.local.env, **/config.local.env.*, **/*.local.env and the four concrete build/environments/env_<env>.sql files, mirroring .gitignore lines 2–8, and re-includes build/environments/*.example.sql which the image needs.
• (b) infra/Dockerfile — COPY build/ ./build/ replaced with an explicit source list. Nothing under build/ reaches the image unless a COPY names it. This is the layer that still holds when someone adds a new config file under build/ without reading this PR.

infra/README.md is new and documents why (item 3 of the issue), alongside a short map of what is in infra/.

Verification

No Docker daemon was available in the session this ran in, so this uses the fallback the issue explicitly allows: comparing the Dockerfile's build-context file list before and after. tests/test_docker_image_secrets.py does that statically — it synthesises the credential files (as the issue's verification step describes), expands the Dockerfile's COPY sources the way Docker would, and asserts none of them is reachable.

Fails on main's Dockerfile/.dockerignore, passes with the fix — both layers, independently:

$ git stash push .dockerignore infra/Dockerfile   # revert to main's versions
$ python -m pytest tests/test_docker_image_secrets.py
FAILED tests/test_docker_image_secrets.py::TestExplicitCopyList::test_no_copy_source_matches_a_sensitive_file
FAILED tests/test_docker_image_secrets.py::TestDockerignoreExcludesSecrets::test_sensitive_files_are_ignored
2 failed, 4 passed in 0.04s

$ git stash pop
$ python -m pytest tests/test_docker_image_secrets.py
6 passed in 0.03s

Build context under build/, before vs after, with synthetic secrets present:

=== build/ files in image context: BEFORE 49 / AFTER 38 ===
=== removed from the image by the fix ===
build/config.local.env
build/config.local.env.new
build/environments/env_dev.sql
build/environments/env_prod.sql
build/environments/env_staging.sql
build/environments/env_test.sql
build/terraform-github-repos/.gitignore
build/terraform-github-repos/main.tf
build/terraform-github-repos/outputs.tf
build/terraform-github-repos/terraform.tfvars.example
build/terraform-github-repos/variables.tf
=== synthetic secrets still reachable after the fix ===
0

All six credential-bearing files gone. build/terraform-github-repos/ also drops out — it is Terraform for GitHub repository management, which the runner never reads, so this is an image-size win rather than a functional change.

No loss of function. test_templates_are_still_copied asserts env_dev.example.sql, env_prod.example.sql, build/deploy_all.sh and build/te_core_schema.sql are all still in the image, so the deploy, load and evals actions keep every file they read. A docker run smoke test could not be executed without a daemon — flagging that as the one piece of the issue's "Done when" not evidenced here.

CI replica (free-tier job)

The integration job needs a PostgreSQL service that was not available here; the free-tier job was run in full.

Unit / regression / security / snapshot tests
  PASSED  : 150
  FAILED  : 0
  ERROR   : 0
  SKIPPED : 0
  NOT RUN : 221  (deselected by the marker filter)
  RESULT: PASS

make lint     -> flake8 clean, bandit clean
make health   -> 84 passed, 0 warnings, 0 failed
evals tier P  -> total 23, passed 23, failed 0, skipped 0

Note for #172

Per the issue, the RV-S1 fix must not reintroduce this exposure by committing a populated env_prod.sql to the image. The explicit COPY list makes that harder by construction: build/environments/*.example.sql is the only pattern reaching build/environments/ in the image, so a concrete env_prod.sql cannot arrive there without deliberately editing a COPY line. #172 should therefore generate it at runtime.

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Generated by Claude Code