gitlab-ci: improve issuebot trigger for merge requests

This should hopefully provide reliable triggering for issuebot on merge
requests.  Before, detecting the merge request number was happening on the
receiving side, and it had weird issues.

.gitlab-ci.yml

@@ -7,7 +7,6 @@ lint:
       - schedules
       - pipelines
   before_script:
-    - ./tools/trigger-issuebot
     - printf "Package\x3a androguard fdroidserver python3-asn1crypto python3-ruamel.yaml\nPin\x3a release a=stretch-backports\nPin-Priority\x3a 500\n" > /etc/apt/preferences.d/debian-stretch-backports.pref
     - echo "deb http://deb.debian.org/debian/ stretch-backports main" > /etc/apt/sources.list.d/backports.list
     - apt-get update
@@ -59,6 +58,18 @@ lint:
     - ./tools/check-metadata-summary-whitespace.py || export EXITVALUE=1
     - exit $EXITVALUE
 
+trigger-issuebot:
+  image: alpine
+  only:
+    - branches
+  except:
+    - master@fdroid/fdroiddata
+  variables:
+    GIT_DEPTH: "1"
+  script:
+    - apk add --no-cache bash curl
+    - ./tools/trigger-issuebot
+
 checkupdates_trigger:
   only:
     refs:
@@ -176,6 +187,9 @@ pages:
       - repo/index.xml
       - tmp/apkcache.json
     when: always
+  # needs lots of git history since it has to compare the merge request to current master
+  variables:
+    GIT_DEPTH: "5000"
   script:
     - apt-get update
     - apt-get dist-upgrade

tools/trigger-issuebot

@@ -1,9 +1,29 @@
 #!/bin/bash -e
 
+get_merge_request_iid() {
+    for page in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19; do
+	for mr in `curl --silent ${CI_API_V4_URL}/projects/${project_id}/merge_requests?page=${page} | grep -Eo '"iid": *[0-9]+' | grep -Eo '[0-9]+$'`; do
+	    if curl --silent ${CI_API_V4_URL}/projects/${project_id}/merge_requests/$mr/pipelines \
+		    | grep -Eo "\"id\": *${CI_PIPELINE_ID}," > /dev/null; then
+		echo $mr
+		return 0
+	    fi
+	done
+    done
+}
+
 # insecure "captcha"
 s=$((4`printf "$CI_COMMIT_SHA" | wc -c`-10))
 e=$((s+`echo "$CI_SERVER_HOST" | wc -c`+18))
 issuebot=`cat .issuebot | cut -b${s}-${e}`
+project_id=36528
+CI_MERGE_REQUEST_IID=`get_merge_request_iid`
+
+if test -z "$CI_MERGE_REQUEST_IID"; then
+    echo "$0 No merge request found, not triggering"
+    exit 0
+fi
+
 curl --silent --request POST \
      --form token=$issuebot \
      --form ref=master \
@@ -11,8 +31,9 @@ curl --silent --request POST \
      --form "variables[FROM_CI_COMMIT_REF_SLUG]=$CI_COMMIT_REF_SLUG" \
      --form "variables[FROM_CI_COMMIT_SHA]=$CI_COMMIT_SHA" \
      --form "variables[FROM_CI_JOB_ID]=$CI_JOB_ID" \
+     --form "variables[FROM_CI_MERGE_REQUEST_IID]=$CI_MERGE_REQUEST_IID" \
      --form "variables[FROM_CI_PIPELINE_ID]=$CI_PIPELINE_ID" \
      --form "variables[FROM_CI_PROJECT_PATH]=$CI_PROJECT_PATH" \
      --form "variables[FROM_CI_PROJECT_URL]=$CI_PROJECT_URL" \
-     ${CI_API_V4_URL}/projects/36528/trigger/pipeline > /dev/null \
+     ${CI_API_V4_URL}/projects/${project_id}/trigger/pipeline > /dev/null \
     || echo "$0 failed to post to a merge request"