[ci] simplify overlay scripts

3 files changed, 24 insertions, 19 deletions

diff --git a/dev/ci/ci-common.sh b/dev/ci/ci-common.sh
index 98ad834b4c..fdba690155 100644
--- a/dev/ci/ci-common.sh
+++ b/dev/ci/ci-common.sh
@@ -49,25 +49,34 @@ ls -l "$CI_BUILD_DIR" || true
 
 declare -A overlays
 
-overlay()
+# overlay <project> <giturl> <ref> <prnumber> [<prbranch>]
+#   creates an overlay for project using a given url and branch which is
+#   active for prnumber or prbranch. prbranch defaults to ref.
+function overlay()
 {
     local project=$1
     local ov_url=$2
     local ov_ref=$3
-
-    if ! is_in_projects "$1"; then
-      echo "Error: $1 is not a known project which can be overlayed"
-      exit 1
+    local ov_prnumber=$4
+    local ov_prbranch=$5
+    : "${ov_prbranch:=$ov_ref}"
+
+    if [ "$CI_PULL_REQUEST" = "$ov_prnumber" ] || [ "$CI_BRANCH" = "$ov_prbranch" ]; then
+      if ! is_in_projects "$project"; then
+        echo "Error: $1 is not a known project which can be overlayed"
+        exit 1
+      fi
+
+      overlays[${project}_URL]=$ov_url
+      overlays[${project}_REF]=$ov_ref
     fi
-
-    overlays[${project}_URL]=$ov_url
-    overlays[${project}_REF]=$ov_ref
 }
 
 set +x
 for overlay in "${ci_dir}"/user-overlays/*.sh; do
     # shellcheck source=/dev/null
-    . "${overlay}"
+    # the directoy can be empty
+    if [ -e "${overlay}" ]; then . "${overlay}"; fi
 done
 
 # shellcheck source=ci-basic-overlay.sh
diff --git a/dev/ci/user-overlays/README.md b/dev/ci/user-overlays/README.md
index 3f9ad5e878..14ee5e4199 100644
--- a/dev/ci/user-overlays/README.md
+++ b/dev/ci/user-overlays/README.md
@@ -21,14 +21,11 @@ and the branch name), then a `.sh` extension (`[0-9]{5}-[a-zA-Z0-9-_]+.sh`).
 Example: `13128-SkySkimmer-noinstance.sh` containing
 
 ```
-if [ "$CI_PULL_REQUEST" = "13128" ] || [ "$CI_BRANCH" = "noinstance" ]; then
-
-    overlay elpi https://github.com/SkySkimmer/coq-elpi noinstance
-
-fi
+overlay elpi https://github.com/SkySkimmer/coq-elpi noinstance 13128
 ```
 
-(`CI_PULL_REQUEST` and `CI_BRANCH` are set in [`ci-common.sh`](../ci-common.sh))
+See [`ci-common.sh`](../ci-common.sh) for the detailed documentation of
+the `overlay` function.
 
 ### Branching conventions
 
diff --git a/dev/tools/create_overlays.sh b/dev/tools/create_overlays.sh
index 78ed27ba03..ac8fd1676d 100755
--- a/dev/tools/create_overlays.sh
+++ b/dev/tools/create_overlays.sh
@@ -42,7 +42,7 @@ OVERLAY_BRANCH=$(git rev-parse --abbrev-ref HEAD)
 OVERLAY_FILE=$(mktemp overlay-XXXX)
 
 # Create the overlay file
-printf 'if [ "$CI_PULL_REQUEST" = "%s" ] || [ "$CI_BRANCH" = "%s" ]; then\n\n' "$PR_NUMBER" "$OVERLAY_BRANCH" > "$OVERLAY_FILE"
+> "$OVERLAY_FILE"
 
 # We first try to build the contribs
 while test $# -gt 0
@@ -66,12 +66,11 @@ do
     make ci-$_CONTRIB_NAME || true
     setup_contrib_git $_CONTRIB_DIR $_CONTRIB_GITPUSHURL
 
-    echo "    overlay ${_CONTRIB_NAME} $_CONTRIB_GITURL $OVERLAY_BRANCH" >> $OVERLAY_FILE
+    echo "overlay ${_CONTRIB_NAME} $_CONTRIB_GITURL $OVERLAY_BRANCH $PR_NUMBER" >> $OVERLAY_FILE
     echo "" >> $OVERLAY_FILE
     shift
 done
 
-# End the file; copy to overlays folder.
-echo "fi" >> $OVERLAY_FILE
+# Copy to overlays folder.
 PR_NUMBER=$(printf '%05d' "$PR_NUMBER")
 mv $OVERLAY_FILE dev/ci/user-overlays/$PR_NUMBER-$DEVELOPER_NAME-${OVERLAY_BRANCH///}.sh