blogex: CRAP scores as a Lens sensor (ex_crap)

Same wiring as app: `crap` reads the export from `test.coverage`, runs in
MIX_ENV=test, and refuses to score when the export is absent.

Baseline at the default threshold (30): 12 files, 59 functions, worst score
6.00. Nothing to fix; blogex's CRAP ceiling is its coverage ceiling, which the
behavior-test yaks already own.

blogex/Makefile

@@ -3,7 +3,7 @@
 MISE_BIN ?= mise
 MISE_EXEC = $(MISE_BIN) exec --
 
-.PHONY: check precommit deps compile test test.coverage coverage format verify
+.PHONY: check precommit deps compile test test.coverage coverage crap format verify
 
 # Cheap static gate for this library (no database, no coverage). Runs from the
 # root `make check`, which loops app then blogex.
@@ -44,6 +44,20 @@ coverage:
 	@test -f cover/default.coverdata || { echo "coverage: no exported coverage - run 'make test.coverage' first" >&2; exit 1; }
 	$(MISE_EXEC) mix test.coverage
 
+# Enforce CRAP scores (complexity x coverage) from the same export. No test run.
+# Runs in MIX_ENV=test because that is the environment the export came from:
+# running in dev would compile a second build and score against a different set
+# of modules. The guard is load-bearing for the same reason as `coverage`:
+# ex_crap falls back to 0% coverage when the export is missing, which would
+# report scores that are pessimistic instead of absent - a false failure is
+# less bad than a false pass, but neither is acceptable in the Lens pass.
+#
+# Threshold is ex_crap's default (30); whether to ratchet it down is an open
+# decision tracked in the "ratchets, deferred decisions, handoff practice" yak.
+crap:
+	@test -f cover/default.coverdata || { echo "crap: no exported coverage - run 'make test.coverage' first" >&2; exit 1; }
+	MIX_ENV=test $(MISE_EXEC) mix crap
+
 # Format code
 format:
 	$(MISE_EXEC) mix format
@@ -58,6 +72,7 @@ format:
 #   - coverage   (yak: coverage floors + framework-glue exclusions policy)
 #                  WIRED below (test.coverage + coverage).
 #   - crap       (yak: CRAP scores with ex_crap (both apps))
+#                  WIRED below (crap); reuses the coverage export.
 #   - mutation   (yak: mutation testing with muex — a sensor, not a gate)
 #
 # The suite runs FIRST: it is what produces the coverage export that the
@@ -65,7 +80,7 @@ format:
 # `mix test --cover --export-coverage` exports instead of printing a summary,
 # and reporting through `mix test.coverage` keeps it to one suite run.) Sensors
 # still run cheapest-first among themselves.
-VERIFY_SENSORS := coverage
+VERIFY_SENSORS := coverage crap
 
 verify:
 	@echo "==> verify(blogex): suite (coverage exported), then sensors [$(VERIFY_SENSORS)]"

blogex/mix.exs

@@ -46,7 +46,8 @@ defmodule Blogex.MixProject do
       {:jason, "~> 1.4"},
       {:plug, "~> 1.15"},
       {:ex_doc, "~> 0.34", only: :dev, runtime: false},
-      {:rustler, "~> 0.38.0", optional: true}
+      {:rustler, "~> 0.38.0", optional: true},
+      {:ex_crap, "~> 0.1.1", only: [:dev, :test], runtime: false}
     ]
   end
 

blogex/mix.lock

@@ -1,6 +1,8 @@
 %{
+  "boundary": {:hex, :boundary, "0.11.0", "56cff565b5565930765e02782281b022935fe8c2e1504543c8c1b44b85893b40", [:mix], [], "hexpm", "b9297a96ea14c0e63dbd77b8135e0d483f9c6f34ed1c9dee4b3fea82c596f55a"},
   "earmark": {:hex, :earmark, "1.4.48", "5f41e579d85ef812351211842b6e005f6e0cef111216dea7d4b9d58af4608434", [:mix], [], "hexpm", "a461a0ddfdc5432381c876af1c86c411fd78a25790c75023c7a4c035fdc858f9"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.44", "f20830dd6b5c77afe2b063777ddbbff09f9759396500cdbe7523efd58d7a339c", [:mix], [], "hexpm", "4778ac752b4701a5599215f7030989c989ffdc4f6df457c5f36938cc2d2a2750"},
+  "ex_crap": {:hex, :ex_crap, "0.1.1", "c1770e7ce1843f304a27f5d32bfa867a340140e337684ee1929c770b2499f884", [:mix], [{:boundary, "~> 0.10", [hex: :boundary, repo: "hexpm", optional: false]}], "hexpm", "ada5d59bce442c1a8a987cb5328cbf4469fb56eb8d04641886f2199569a75b12"},
   "ex_doc": {:hex, :ex_doc, "0.40.1", "67542e4b6dde74811cfd580e2c0149b78010fd13001fda7cfeb2b2c2ffb1344d", [:mix], [{:earmark_parser, "~> 1.4.44", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "bcef0e2d360d93ac19f01a85d58f91752d930c0a30e2681145feea6bd3516e00"},
   "jason": {:hex, :jason, "1.4.5", "2e3a008590b0b8d7388c20293e9dcc9cf3e5d642fd2a114e4cbbb52e595d940a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0 or ~> 3.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b0c823996102bcd0239b3c2444eb00409b72f6a140c1950bc8b457d836b30684"},
   "makeup": {:hex, :makeup, "1.2.2", "882d46dc0905e9ff7abf2aab61a7e6b3dcc555533977d8a23b06019e6c89ac94", [:mix], [{:nimble_parsec, "~> 1.4", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "9a1a24e5b343b8ae16abea0822c10a6f75da27af7fa802ada5251f7579bfccfa"},