Replace Codecov with a coverage badge from the documentation site

.github/workflows/docs.yml

@@ -24,13 +24,28 @@ jobs:
       - name: Checkout
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with:
+          submodules: true
           fetch-depth: 0
+      - name: Setup Zulu JDK 7
+        uses: actions/setup-java@b6effb05e454b25005698d916606bdc6ffcbf961 # v5
+        with:
+          distribution: zulu
+          java-version: '7'
       - name: Setup Temurin JDK 25
         uses: actions/setup-java@b6effb05e454b25005698d916606bdc6ffcbf961 # v5
         with:
           distribution: temurin
           java-version: '25'
           cache: maven
+      # JaCoCo report for the coverage badge, published by `just all` under current/coverage
+      - name: Run tests with coverage
+        run: |
+          ./mvnw -B -C -ntp -V \
+            -Darch.id=amd64 \
+            -Dnative.cc=gcc \
+            -Dsurefire.reportFormat=plain \
+            -Pcoverage \
+            verify
       - name: Install uv
         uses: astral-sh/setup-uv@c18668ad3cf93ea998bef934396af7bb5c839dc7 # v10.2.0
       - name: Install just

.github/workflows/test.yml

@@ -13,10 +13,6 @@ jobs:
   linux:
     name: Linux test
     runs-on: ${{ matrix.runs-on }}
-    permissions:
-      contents: read
-      # Codecov upload via OIDC
-      id-token: write
     strategy:
       fail-fast: false
       matrix:
@@ -66,13 +62,6 @@ jobs:
             -Dsurefire.reportFormat=plain \
             ${{ matrix.maven-flags }} \
             verify
-      - name: Upload coverage to Codecov
+      - name: Summarize coverage
         if: matrix.coverage
-        uses: codecov/codecov-action@303a32d7a59b442fa8d48b6a1cc6825c09c847a5 # v7.1.1
-        with:
-          files: target/site/jacoco/jacoco.xml
-          disable_search: true
-          # OIDC tokens are not available to pull requests from other repositories, which use tokenless upload instead.
-          # Don't use head.repo.fork here: this repository is itself a fork, so that is always true.
-          use_oidc: ${{ github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository }}
-          fail_ci_if_error: false
+        run: python3 scripts/jacoco_summary.py target/site/jacoco/jacoco.csv >> "$GITHUB_STEP_SUMMARY"

README.md

@@ -1,7 +1,7 @@
 # LZ4 Java
 
 [![Maven Central](https://img.shields.io/maven-central/v/at.yawk.lz4/lz4-java)](https://central.sonatype.com/artifact/at.yawk.lz4/lz4-java)
-[![codecov](https://codecov.io/gh/yawkat/lz4-java/graph/badge.svg)](https://codecov.io/gh/yawkat/lz4-java)
+[![Coverage](https://img.shields.io/endpoint?url=https%3A%2F%2Flz4-java.yawk.at%2Fcurrent%2Fcoverage%2Fbadge.json)](https://lz4-java.yawk.at/current/coverage/)
 [![OpenSSF Best Practices](https://www.bestpractices.dev/projects/14930/badge)](https://www.bestpractices.dev/projects/14930)
 [![OpenSSF Scorecard](https://api.scorecard.dev/projects/github.com/yawkat/lz4-java/badge)](https://scorecard.dev/viewer/?uri=github.com/yawkat/lz4-java)
 

docs/justfile

@@ -26,6 +26,7 @@ template NAME TAG: (repo TAG)
   import semver
   import mistune
   import os
+  import re
   import pygments
   import pygments.lexers
   import pygments.formatters
@@ -37,6 +38,20 @@ template NAME TAG: (repo TAG)
 
   selected_version_actual = '{{TAG}}' if '{{TAG}}' != '{{latest_version_name}}' else '{{latest_version}}'
 
+  def readme_source():
+    text = open('{{build}}/repo/lz4-java-{{TAG}}/README.md').read()
+    if '{{TAG}}' != '{{latest_version_name}}':
+      # The README badges show the state of the main branch. On pages for older versions, pin the Maven Central badge to
+      # that version and drop the others.
+      version = '{{TAG}}'[1:]
+      text = re.sub(
+          r'^\[!\[Maven Central\]\(https://img\.shields\.io/maven-central/v/([^/)]+)/([^/)]+)\)\]\([^)]*\)$',
+          lambda m: f'[![Maven Central](https://img.shields.io/badge/maven--central-v{version}-blue)]'
+                    f'(https://central.sonatype.com/artifact/{m[1]}/{m[2]}/{version})',
+          text, flags=re.M)
+      text = re.sub(r'^\[!\[(?!Maven Central\]).*\n', '', text, flags=re.M)
+    return text
+
   html_formatter = pygments.formatters.HtmlFormatter()
   class PygmentsRenderer(mistune.HTMLRenderer):
     def block_code(self, code, info=None):
@@ -61,7 +76,7 @@ template NAME TAG: (repo TAG)
         selected_version='{{TAG}}',
         selected_version_actual=selected_version_actual,
         path_javadoc='{{path_javadoc}}',
-        readme=lambda: mistune.create_markdown(renderer=PygmentsRenderer(), plugins=['table'])(open('{{build}}/repo/lz4-java-{{TAG}}/README.md').read()),
+        readme=lambda: mistune.create_markdown(renderer=PygmentsRenderer(), plugins=['table'])(readme_source()),
         pygments_style=lambda: html_formatter.get_style_defs()
         ))
 
@@ -96,6 +111,13 @@ rewrite-version-links:
       html = html.replace('</title>', '</title><link rel="stylesheet" href="' + str(to_root) + '/common.css"><link rel="stylesheet" href="' + str(to_root) + '/javadoc.css">')
     p.write_text(html)
 
+# Publish the JaCoCo report of the working tree, if it was built with `./mvnw -Pcoverage verify`
+coverage:
+  if [ -f ../target/site/jacoco/jacoco.csv ]; then \
+    cp -r ../target/site/jacoco '{{build}}/site/{{latest_version_name}}/coverage' && \
+    python3 ../scripts/jacoco_summary.py ../target/site/jacoco/jacoco.csv --badge '{{build}}/site/{{latest_version_name}}/coverage/badge.json'; \
+  fi
+
 prepare:
   rm -rf '{{build}}/site'
   mkdir -p '{{build}}/site'
@@ -105,5 +127,5 @@ log:
   @echo "Available tags: {{all_versions}}"
   @echo "Current tag: {{latest_version}}"
 
-all: log prepare (version latest_version_name) && rewrite-version-links
+all: log prepare (version latest_version_name) && coverage rewrite-version-links
   set -e; for v in {{all_versions}}; do just 'all_versions={{all_versions}}' 'latest_version={{latest_version}}' version "$v"; done

pom.xml

@@ -342,7 +342,7 @@
 
   <profiles>
     <profile>
-      <!-- Record test coverage of the Java code with JaCoCo, report in target/site/jacoco/jacoco.xml -->
+      <!-- Record test coverage of the Java code with JaCoCo, report in target/site/jacoco -->
       <id>coverage</id>
       <build>
         <plugins>

scripts/jacoco_summary.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+"""Summarize line coverage from a JaCoCo CSV report.
+
+Prints a Markdown summary line, and with --badge also writes a shields.io endpoint badge JSON file.
+"""
+import argparse
+import csv
+import json
+
+parser = argparse.ArgumentParser(description=__doc__)
+parser.add_argument("csv", help="JaCoCo CSV report, e.g. target/site/jacoco/jacoco.csv")
+parser.add_argument("--badge", help="write shields.io endpoint badge JSON to this file")
+args = parser.parse_args()
+
+missed = covered = 0
+with open(args.csv, newline="") as f:
+    for row in csv.DictReader(f):
+        missed += int(row["LINE_MISSED"])
+        covered += int(row["LINE_COVERED"])
+total = missed + covered
+pct = 100 * covered / total
+
+print(f"Line coverage: **{pct:.1f}%** ({covered} of {total} lines)")
+
+if args.badge:
+    color = "brightgreen" if pct >= 80 else "yellow" if pct >= 60 else "red"
+    with open(args.badge, "w") as f:
+        json.dump({"schemaVersion": 1, "label": "coverage", "message": f"{pct:.1f}%", "color": color}, f)