From 25265dab63d6eaff370098068100c0305e447086 Mon Sep 17 00:00:00 2001
From: Chris Bargmann <github@cbrgm.net>
Date: Wed, 12 Aug 2026 15:11:11 +0200
Subject: [PATCH] ci(gen): ignore go-github version-only changes in apidiff
 gate

---
 scripts/apidiff.sh | 47 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 44 insertions(+), 3 deletions(-)

diff --git a/scripts/apidiff.sh b/scripts/apidiff.sh
index 6524a821..d8a4d96d 100755
--- a/scripts/apidiff.sh
+++ b/scripts/apidiff.sh
@@ -1,10 +1,48 @@
 #!/usr/bin/env bash
 # Fail if the exported API of ./githubevents changed incompatibly vs a base ref.
+#
+# A go-github major bump (e.g. v89 -> v90) re-exports every event type under a
+# new import path, which apidiff reports as incompatible even though nothing in
+# our own surface changed. Those version-only diffs are filtered out here so the
+# gate still catches real breaks (renames, signature changes, removals, and any
+# real field change go-github makes to an event type) without blocking routine
+# dependency bumps.
 set -euo pipefail
 
 BASE="${1:-origin/main}"
 PKG="./githubevents"
 
+# real_incompatible_changes reads apidiff output on stdin and prints only the
+# incompatible changes that are NOT purely a go-github version-path bump. A
+# "changed from X to Y" line whose X and Y are identical once the go-github
+# major (/vN/) is normalized away is a version-only change and is dropped.
+real_incompatible_changes() {
+  local line norm rest from to in_incompat=0
+  while IFS= read -r line; do
+    case "$line" in
+      "Incompatible changes:") in_incompat=1; continue ;;
+      "Compatible changes:") in_incompat=0; continue ;;
+      "") in_incompat=0; continue ;;
+    esac
+    [ "$in_incompat" -eq 1 ] || continue
+    case "$line" in "- "*) ;; *) continue ;; esac
+
+    norm="$(printf '%s' "$line" | sed 's#go-github/v[0-9]\{1,\}#go-github/vN#g')"
+    case "$norm" in
+      *" changed from "*" to "*)
+        rest="${norm#* changed from }"
+        from="${rest% to *}"
+        to="${rest#* to }"
+        [ "$from" = "$to" ] && continue
+        ;;
+    esac
+    printf '%s\n' "$line"
+  done
+}
+
+# When sourced for testing, stop here.
+[ "${APIDIFF_LIB:-0}" = 1 ] && return 0
+
 command -v apidiff >/dev/null 2>&1 || { echo "apidiff not installed; run 'make tools'"; exit 1; }
 
 work="$(mktemp -d)"
@@ -17,8 +55,11 @@ git worktree add --quiet --detach "$base_wt" "$BASE"
 
 out="$(apidiff "$work/base.api" "$PKG")"
 printf '%s\n' "$out"
-if printf '%s\n' "$out" | grep -q '^Incompatible changes:'; then
-  echo ">> incompatible API changes detected"
+
+real="$(printf '%s\n' "$out" | real_incompatible_changes)"
+if [ -n "$real" ]; then
+  echo ">> incompatible API changes detected (beyond go-github version bump):"
+  printf '%s\n' "$real"
   exit 1
 fi
-echo ">> API compatible"
+echo ">> API compatible (go-github version-only changes ignored)"