fix(webhook): detach async goroutine from pooled echo.Context

pkg/modules/webhook/pool_safe_context.go

@@ -0,0 +1,58 @@
+package webhook
+
+import (
+	"sync"
+
+	"github.com/labstack/echo/v4"
+)
+
+// poolSafeContext wraps an [echo.Context] and keeps a private snapshot of
+// the values that downstream middleware and route handlers read from the
+// store. Echo returns an [echo.Context] to its sync.Pool as soon as the
+// synchronous handler returns, including when the webhook middleware
+// returns [api.ErrAsyncProcess]. A concurrent request can then claim the
+// recycled context and c.Reset() wipes the shared store out from under
+// the webhook goroutine, which causes any
+// `c.Get("logger").(*slog.Logger)`-style assertion further down the
+// chain to panic on a nil value.
+//
+// Wrapping c before handing it to the goroutine insulates the async work
+// from pool reuse: Get/Set read and write the private store while every
+// other [echo.Context] method delegates to the embedded context for
+// anything the downstream might still need.
+type poolSafeContext struct {
+	echo.Context
+	mu    sync.RWMutex
+	store map[string]any
+}
+
+// newPoolSafeContext snapshots the given keys from c into a detached
+// store and returns a wrapper whose Get/Set operate on that store
+// exclusively. Keys absent from c are omitted; the wrapper still
+// returns nil for them, matching [echo.Context.Get] behavior.
+func newPoolSafeContext(c echo.Context, keys ...string) *poolSafeContext {
+	store := make(map[string]any, len(keys))
+	for _, key := range keys {
+		if v := c.Get(key); v != nil {
+			store[key] = v
+		}
+	}
+	return &poolSafeContext{Context: c, store: store}
+}
+
+// Get returns the value stored in the detached store, not the embedded
+// context's pooled store.
+func (p *poolSafeContext) Get(key string) any {
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	return p.store[key]
+}
+
+// Set writes to the detached store, not the embedded context's pooled
+// store. This prevents downstream middleware writes from leaking into a
+// later request that claims the same pooled context.
+func (p *poolSafeContext) Set(key string, val any) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.store[key] = val
+}