Fix and simplify check-python dev script (#1934)

I revisited and simplified a few things in the `check-python` dev
script, partially as follow-up of
tiny-pilot/tinypilot-pro#1714:

- Fix `ADDITIONAL_PY_SCRIPTS` (which was outdated) for a dynamic lookup
mechanism, which ensures to always catch all scripts in `scripts/`.
- Consolidate `check-for-init-python-files` into the `check-python`
script. It seemed weird to me to have this script separately and
everything else embedded.
- Fix some bash quotes (`"`→`'`)

This structure also makes it a bit easier to include the front panel
sources here: I realized that the `check-python` script also doesn’t
sufficiently account for the front panel. So for the upstream merge, I
plan to add these changes ([see this Pro branch I used for
testing](tiny-pilot/tinypilot-pro@master...check-python)):

- 👉 In Pro’s CircleCI config, we have to install the front panel venv
before running `check-python`. That actually triggers some missing
ignore-directives (e.g., in `.yapfignore`), that also would show up when
running locally.
- 👉 `ruff` doesn’t cover the front panel, so we have to add it there.
- ✅ `yapf` already covers the front panel.
- ❌ `coverage` doesn’t include the front panel – we don’t have any tests
in the front panel, but I also wasn’t able to figure out how to make it
even look there…
- ❌ `pylint` doesn’t include the front panel – unfortunately, [I wasn’t
able to make that happen
trivially](tiny-pilot/tinypilot-pro#1731), so
we should look into this separately – there are some minor style
violations there.

I think the aforementioned problems would profit from a [revised project
structure](tiny-pilot/tinypilot-pro#1721),
where we properly share dev dependencies for both our Python services.
The current nested structure doesn’t seem to lend itself as nicely for
this.

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---------

Co-authored-by: Jan Heuermann <jan@jotaen.net>

Author: jotaen4tinypilot

dev-scripts/check-all

@@ -14,7 +14,6 @@ set -x
 set -u
 
 ./dev-scripts/check-bash
-./dev-scripts/check-for-init-files
 ./dev-scripts/check-javascript
 ./dev-scripts/check-privilege-guard
 ./dev-scripts/check-python

dev-scripts/check-for-init-py-files

@@ -11,44 +11,58 @@ set -x
 # Exit on unset variable.
 set -u
 
-# Location of app source files.
-SOURCE_DIR="app"
-
-ADDITIONAL_PY_SCRIPTS=()
-ADDITIONAL_PY_SCRIPTS+=("scripts/render-template")
-ADDITIONAL_PY_SCRIPTS+=("scripts/update-service")
-
-# Location of virtualenv.
-VIRTUALENV_DIR=venv
-
-./dev-scripts/check-for-init-py-files
-
 # Delete pyc files from previous builds.
 find . \
-  -name "*.pyc" \
+  -name '*.pyc' \
   -type f \
-  -not -path "./${VIRTUALENV_DIR}/*" \
+  -not -path './venv/*' \
   -delete
 
 # Run unit tests and calculate code coverage.
 # Load module `app.log` to initialize our custom logger.
 coverage run \
-  --source "$SOURCE_DIR" \
-  --omit "*_test.py" \
+  --source app/ \
+  --omit '*_test.py' \
   --module \
-    unittest discover --pattern "*_test.py" \
+    unittest discover --pattern '*_test.py' \
     app.log
 coverage report
 
+# Check for Python init files.
+INIT_FILES_OK=true
+while read -r directory; do
+  if [[ ! -f "${directory}/__init__.py" ]]; then
+    printf "Directory missing __init__.py file: %s\n" "${directory}" >&2
+    INIT_FILES_OK=false
+  fi
+done < <(
+  find . \
+    -type f \
+    -name '*.py' \
+    -not -path './venv/*' \
+    -not -path './.git/*' \
+    -exec dirname {} \; \
+    | sort --unique
+)
+"${INIT_FILES_OK}" || exit 1
+
 # Check that source has correct formatting.
 yapf --diff --recursive ./
 
+# Gather names of all Python scripts in the scripts/ folder.
+PYTHON_SCRIPTS=()
+while read -r line; do
+  PYTHON_SCRIPTS+=("${line}")
+done < <(grep --recursive --files-with-matches '^#!.*python' scripts/)
+readonly PYTHON_SCRIPTS
+
 # Run static analysis for Python bugs/cruft.
 ruff check \
-  "${SOURCE_DIR}/" \
-  "${ADDITIONAL_PY_SCRIPTS[@]}"
+  app/ \
+  "${PYTHON_SCRIPTS[@]}"
 
 # Check for other style violations.
-PYTHONPATH="${SOURCE_DIR}" \
+PYTHONPATH='app/' \
   pylint \
-  "${SOURCE_DIR}" "${ADDITIONAL_PY_SCRIPTS[@]}"
+  app/ \
+  "${PYTHON_SCRIPTS[@]}"