Resolve maven dependencies before building

This tries to solve build timeouts while downloading dependencies.
Also the job timeout for PRs is 30 minutes - if it takes longer,
something is wrong.

.ci/build-pr.sh

@@ -3,13 +3,14 @@
 source $(dirname $0)/inc/logger.inc
 source $(dirname $0)/inc/setup-secrets.inc
 source $(dirname $0)/inc/regression-tester.inc
+source $(dirname $0)/inc/maven-dependencies.inc
 source ${HOME}/java.env
 
 set -e
 #set -x
 
-export MAVEN_OPTS="-Dmaven.wagon.httpconnectionManager.ttlSeconds=180 -Dmaven.wagon.http.retryHandler.count=3"
-#export MAVEN_OPTS="-Dhttp.keepAlive=false -Dmaven.wagon.http.pool=false"
+maven_dependencies_resolve
+
 ./mvnw -e -V clean verify
 
 # Danger is executed only on the linux runner

.ci/inc/maven-dependencies.inc

@@ -0,0 +1,25 @@
+
+#
+# On azure, outgoing idle connection are dropped after 4 minutes.
+# Usually, you can configure wagon with ttl. But these settings are
+# ignored, as soon as dokka-maven-plugin is loaded.
+# dokka-maven-plugin tries to load additional dependencies at runtime
+# and injects a different http client, which is not configured correctly
+# and thus maven fails if it tries to download later in the build process
+# further dependencies.
+#
+# The workaround applied here is: first resolve all dependencies,
+# then explicitly get dokka-maven-plugin and then resolve all plugins
+# execpt for dokka-maven-plugin, as it does not play well with dependency-plugin.
+#
+function maven_dependencies_resolve() {
+    dokka_version=$(./mvnw -q -Dexec.executable="echo" -Dexec.args='${dokka.version}' --non-recursive org.codehaus.mojo:exec-maven-plugin:3.0.0:exec)
+
+    ./mvnw dependency:resolve
+    ./mvnw dependency:get -DgroupId=org.jetbrains.dokka \
+           -DartifactId=dokka-maven-plugin \
+           -Dversion=${dokka_version} \
+           -Dpackaging=jar \
+           -DremoteRepositories=jcenter::default::https://jcenter.bintray.com/
+    ./mvnw dependency:resolve-plugins -DexcludeGroupIds=org.jetbrains.dokka
+}

.github/workflows/pull-requests.yml

@@ -7,6 +7,7 @@ jobs:
   build:
     runs-on: ${{ matrix.os }}
     continue-on-error: false
+    timeout-minutes: 30
     if: "!contains(github.event.head_commit.message, '[skip ci]')"
     strategy:
       matrix:
@@ -34,6 +35,7 @@ jobs:
         run: .ci/build-pr.sh
         shell: bash
         env:
+          MAVEN_OPTS: -Dmaven.wagon.httpconnectionManager.ttlSeconds=180 -Dmaven.wagon.http.retryHandler.count=3
           PMD_CI_SECRET_PASSPHRASE: ${{ secrets.PMD_CI_SECRET_PASSPHRASE }}
           PMD_CI_BRANCH: ${{ github.ref }}
           PMD_CI_PULL_REQUEST_NUMBER: ${{ github.event.number }}

.github/workflows/troubleshooting.yml

@@ -1,12 +1,11 @@
 name: troubleshooting
 
-on: pull_request
+on: workflow_dispatch
 
 jobs:
   build:
     runs-on: ${{ matrix.os }}
     continue-on-error: false
-    if: "!contains(github.event.head_commit.message, '[skip ci]')"
     strategy:
       matrix:
         #os: [ ubuntu-latest, windows-latest, macos-latest ]