ci: native coverage report instead of excoveralls

excoveralls 0.18.5 fails on OTP 27 (:cover.compile_beam MatchError), so
the coverage job now runs mix test --cover, uploads the HTML report as
an artifact and comments the total on pull requests. mix.exs drops the
excoveralls dependency and test_coverage tool.

Author: gilbertwong96

.github/workflows/ci.yml

@@ -70,22 +70,35 @@ jobs:
       - name: Fetch dependencies
         run: mix deps.get
 
-      - name: Probe native coverage first
+      - name: Generate coverage report
         env:
           MIX_ENV: test
-        run: mix test --cover 2>&1 | tail -5
+        run: |
+          mix test --cover > /tmp/cover.log 2>&1
+          tail -6 /tmp/cover.log
+
+      - name: Extract total coverage
+        id: total
+        run: |
+          pct=$(grep '| Total' /tmp/cover.log | awk -F'|' '{gsub(/ /, "", $2); print $2}')
+          echo "pct=$pct" >> "$GITHUB_OUTPUT"
 
       - name: Upload coverage artifact
         uses: actions/upload-artifact@v4
         with:
-          name: cobertura.xml
-          path: cover/cobertura.xml
+          name: coverage-report
+          path: cover/
 
-      - name: Comment coverage summary on pull request
+      - name: Comment coverage on pull request
         if: github.event_name == 'pull_request'
-        uses: irongut/CodeCoverageSummary@v1.3.0
+        env:
+          COVERAGE_PCT: ${{ steps.total.outputs.pct }}
+        uses: actions/github-script@v7
         with:
-          filename: cover/cobertura.xml
-          badge: true
-          format: markdown
-          output: both
+          script: |
+            await github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number,
+              body: `Coverage: **${process.env.COVERAGE_PCT}** (HTML report in the coverage-report artifact)`
+            })

mix.exs

@@ -16,8 +16,6 @@ defmodule LovelyMermaid.MixProject do
       # Quality gates
       dialyzer: [plt_add_apps: [:mix]],
 
-      # Coverage
-      test_coverage: [tool: ExCoveralls],
 
       # Package
       description: "Render Mermaid diagrams as Unicode box-drawing art for terminals",
@@ -49,8 +47,7 @@ defmodule LovelyMermaid.MixProject do
       {:ex_slop, "~> 0.4", only: [:dev, :test], runtime: false},
       {:reach, "~> 2.8", only: [:dev, :test], runtime: false},
       {:credo, "~> 1.7", only: [:dev, :test], runtime: false},
-      {:dialyxir, "~> 1.4", only: [:dev, :test], runtime: false},
-      {:excoveralls, "~> 0.18", only: :test, runtime: false}
+      {:dialyxir, "~> 1.4", only: [:dev, :test], runtime: false}
     ]
   end
 

mix.lock

@@ -8,7 +8,6 @@
   "ex_dna": {:hex, :ex_dna, "1.5.4", "5a636109aeccca1c6df074367f53dc096f4280e90c075f5537ce8b8b4a843343", [:mix], [{:credo, "~> 1.7", [hex: :credo, repo: "hexpm", optional: true]}, {:gen_lsp, "~> 0.11", [hex: :gen_lsp, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: true]}], "hexpm", "66e6c7157127f023a219be16f2aa8e3a18c698e7a106f78bb24304b34df8034b"},
   "ex_doc": {:hex, :ex_doc, "0.40.3", "4a972ffe64bc07dc605af487e98fc19b72a4185f55ca031b94c0552d6071c1d9", [: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", "2756e357742fecd9749b489b85d67c9ce99c465f2e75728d9e6dc8d704b973de"},
   "ex_slop": {:hex, :ex_slop, "0.4.4", "8ca277b902e93193eb3545e414c309026a51204e5eb7d6ada5ff96555de6abcb", [:mix], [{:credo, "~> 1.7", [hex: :credo, repo: "hexpm", optional: false]}], "hexpm", "03ef1b2553ebad45c8ceb3e482eed5f1ccd08fc992215a9da0ef6196935107e2"},
-  "excoveralls": {:hex, :excoveralls, "0.18.5", "e229d0a65982613332ec30f07940038fe451a2e5b29bce2a5022165f0c9b157e", [:mix], [{:castore, "~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "523fe8a15603f86d64852aab2abe8ddbd78e68579c8525ae765facc5eae01562"},
   "file_system": {:hex, :file_system, "1.1.1", "31864f4685b0148f25bd3fbef2b1228457c0c89024ad67f7a81a3ffbc0bbad3a", [:mix], [], "hexpm", "7a15ff97dfe526aeefb090a7a9d3d03aa907e100e262a0f8f7746b78f8f87a5d"},
   "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"},
   "libgraph": {:hex, :libgraph, "0.16.0", "3936f3eca6ef826e08880230f806bfea13193e49bf153f93edcf0239d4fd1d07", [:mix], [], "hexpm", "41ca92240e8a4138c30a7e06466acc709b0cbb795c643e9e17174a178982d6bf"},