ci: migrate to flint v2 for linting

Replace the v1-era remote bash task and separate markdown lint job with
flint v2, which runs all checks (lychee, markdownlint-cli2,
google-java-format, ktlint, license-header) from a single binary.

- Add flint, google-java-format, ktlint to mise.toml
- Create .github/config/flint.toml with license-header check for
  *.java and *.kt (mirrors spotless config); excludes gradlew,
  spotless.license.java, CHANGELOG.md, licenses/licenses.md
- Add ktlint editorconfig overrides to .editorconfig (mirrors the
  editorConfigOverride() calls in otel.spotless-conventions.gradle.kts)
- Replace reusable-link-check.yml + reusable-markdown-lint-check.yml
  with a single reusable-lint-check.yml running `mise run lint`
- Spotless remains authoritative for formatting; flint provides fast
  local feedback and CI link/markdown/license checking

Signed-off-by: Gregor Zeitlinger <gregor.zeitlinger@grafana.com>

Author: zeitlinger

.editorconfig

@@ -761,3 +761,16 @@ ij_properties_spaces_around_key_value_delimiter = false
 [{*.yaml, *.yml}]
 ij_yaml_keep_indents_on_empty_lines = false
 ij_yaml_keep_line_breaks = true
+
+# ktlint overrides (mirrors otel.spotless-conventions.gradle.kts)
+[{*.kt, *.kts}]
+max_line_length = 160
+continuation_indent_size = 2
+ktlint_standard_no-wildcard-imports = disabled
+ktlint_standard_package-name = disabled
+ktlint_standard_max-line-length = disabled
+ktlint_standard_trailing-comma-on-call-site = disabled
+ktlint_standard_trailing-comma-on-declaration-site = disabled
+ktlint_standard_wrapping = disabled
+ktlint_standard_property-naming = disabled
+ktlint_standard_function-literal = disabled

.github/config/flint.toml

@@ -0,0 +1,10 @@
+[settings]
+exclude = "gradlew|buildscripts/spotless\\.license\\.java|CHANGELOG\\.md|licenses/licenses\\.md"
+
+[checks.license-header]
+text = """
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */"""
+patterns = ["**/*.java", "**/*.kt"]

.github/workflows/build-daily.yml

@@ -25,11 +25,8 @@ jobs:
   muzzle:
     uses: ./.github/workflows/reusable-muzzle.yml
 
-  link-check:
-    uses: ./.github/workflows/reusable-link-check.yml
-
-  markdown-lint-check:
-    uses: ./.github/workflows/reusable-markdown-lint-check.yml
+  lint:
+    uses: ./.github/workflows/reusable-lint-check.yml
 
   publish-snapshots:
     environment: protected

.github/workflows/build-pull-request.yml

@@ -40,15 +40,11 @@ jobs:
     with:
       cache-read-only: true
 
-  # this is not a required check to avoid blocking pull requests if external links break
-  markdown-check:
+  lint:
     # release branches are excluded because the README.md javaagent download link has to be updated
     # on release branches before the release download has been published
     if: "!startsWith(github.ref_name, 'release/') && !startsWith(github.base_ref, 'release/')"
-    uses: ./.github/workflows/reusable-link-check.yml
-
-  markdown-lint-check:
-    uses: ./.github/workflows/reusable-markdown-lint-check.yml
+    uses: ./.github/workflows/reusable-lint-check.yml
 
   required-status-check:
     # test-latest-deps is not included in the required status checks
@@ -63,7 +59,7 @@ jobs:
     needs:
       - common
       - muzzle
-      - markdown-lint-check
+      - lint
     runs-on: ubuntu-latest
     if: always()
     steps:
@@ -73,7 +69,7 @@ jobs:
             !startsWith(github.base_ref, 'release/') &&
             (
               needs.muzzle.result != 'success' ||
-              needs.markdown-lint-check.result != 'success'
+              needs.lint.result != 'success'
             )
           )
         run: exit 1 # fail

.github/workflows/build.yml

@@ -34,14 +34,8 @@ jobs:
     if: "!startsWith(github.ref_name, 'release/')"
     uses: ./.github/workflows/reusable-muzzle.yml
 
-  link-check:
-    # release branches are excluded to avoid unnecessary maintenance if external links break
-    # (and also because the README.md javaagent download link has to be updated on release branches
-    #  before the release download has been published)
+  lint:
+    # release branches are excluded because the README.md javaagent download link has to be updated
+    # on release branches before the release download has been published
     if: "!startsWith(github.ref_name, 'release/')"
-    uses: ./.github/workflows/reusable-link-check.yml
-
-  markdown-lint-check:
-    # release branches are excluded
-    if: "!startsWith(github.ref_name, 'release/')"
-    uses: ./.github/workflows/reusable-markdown-lint-check.yml
+    uses: ./.github/workflows/reusable-lint-check.yml

.github/workflows/reusable-link-check.yml .github/workflows/reusable-lint-check.yml.github/workflows/reusable-link-check.yml renamed to .github/workflows/reusable-lint-check.yml

@@ -1,4 +1,4 @@
-name: Reusable - Link check
+name: Reusable - Lint check
 
 on:
   workflow_call:
@@ -7,7 +7,7 @@ permissions:
   contents: read
 
 jobs:
-  link-check:
+  lint-check:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
@@ -16,16 +16,16 @@ jobs:
 
       - uses: jdx/mise-action@1648a7812b9aeae629881980618f079932869151 # v4.0.1
 
-      - name: Link check for pull requests
+      - name: Lint for pull requests
         if: github.event_name == 'pull_request'
         env:
           GITHUB_TOKEN: ${{ github.token }}
           GITHUB_HEAD_SHA: ${{ github.event.pull_request.head.sha }}
           PR_HEAD_REPO: ${{ github.event.pull_request.head.repo.full_name }}
-        run: mise run lint:links
+        run: mise run lint
 
-      - name: Link check for pushes and scheduled workflows
+      - name: Lint for pushes and scheduled workflows
         if: github.event_name != 'pull_request'
         env:
           GITHUB_TOKEN: ${{ github.token }}
-        run: mise run lint:links --full
+        run: mise run lint

.github/workflows/reusable-markdown-lint-check.yml

@@ -1,6 +1,12 @@
 [tools]
+"cargo:https://github.com/grafana/flint" = "rev:113b8cd5910bfd58881cd520daf02040d25b640e"
 lychee = "0.23.0"
 markdownlint-cli2 = "0.22.0"
+"github:google/google-java-format" = "1.35.0"
+"github:pinterest/ktlint" = "1.8.0"
+
+[env]
+FLINT_CONFIG_DIR = ".github/config"
 
 [settings]
 # Only install tools explicitly defined in the [tools] section above
@@ -12,7 +18,11 @@ windows_executable_extensions = ["sh"]
 windows_default_file_shell_args = "bash"
 use_file_shell_for_executable_tasks = true
 
-# Pick the tasks you need from flint (https://github.com/grafana/flint)
-[tasks."lint:links"]
-description = "Check for broken links in changed files + all local links"
-file = "https://raw.githubusercontent.com/grafana/flint/eded4cd370c729289a6de327a1a26831e10a39b9/tasks/lint/links.sh" # v0.20.2
+[tasks.lint]
+run = "flint run"
+
+[tasks."lint:fix"]
+run = "flint run --fix"
+
+[tasks."lint:pre-commit"]
+run = "flint run --fix --fast-only"