Bug Description
In flow/retriever/router/router.go, the NewRetriever function builds a default router function when config.Router is nil, but then accidentally stores config.Router (which is still nil) into the routerRetriever struct instead of the local router variable. This causes a nil pointer dereference panic when Retrieve() is called without a custom Router configured.
Affected File
flow/retriever/router/router.go
Root Cause
func NewRetriever(ctx context.Context, config *Config) (retriever.Retriever, error) {
// ...
router := config.Router
if router == nil {
// correctly build a default router
var retrieverSet []string
for k := range config.Retrievers {
retrieverSet = append(retrieverSet, k)
}
router = func(ctx context.Context, query string) ([]string, error) {
return retrieverSet, nil
}
}
// ...
return &routerRetriever{
retrievers: config.Retrievers,
router: config.Router, // BUG: should be `router`, not `config.Router`
fusionFunc: fusion,
}, nil
}When config.Router is nil (the common case where the user relies on the default all-retrievers router), the struct field routerRetriever.router is also nil. The Retrieve() method then calls e.router(routeCtx, query), which panics with a nil pointer dereference.
Steps to Reproduce
retrieverA := /* some retriever.Retriever */
retrieverB := /* some retriever.Retriever */
// config.Router is intentionally omitted — expecting the default "all retrievers" behavior
rr, err := router.NewRetriever(ctx, &router.Config{
Retrievers: map[string]retriever.Retriever{
"a": retrieverA,
"b": retrieverB,
},
// Router not set, FusionFunc not set
})
if err != nil {
log.Fatal(err)
}
// PANICS: runtime error: invalid memory address or nil pointer dereference
docs, err := rr.Retrieve(ctx, "some query")Expected Behavior
NewRetriever should store the resolved (possibly default) router variable into the struct, not config.Router. When config.Router is nil, all registered retrievers should be queried (the intended default behavior).
Fix
Change line in NewRetriever:
// Before (buggy)
return &routerRetriever{
retrievers: config.Retrievers,
router: config.Router,
fusionFunc: fusion,
}, nil
// After (fixed)
return &routerRetriever{
retrievers: config.Retrievers,
router: router,
fusionFunc: fusion,
}, nilImpact
Any caller that omits Config.Router (relying on the documented default behavior of querying all retrievers) will encounter a nil pointer dereference panic at runtime instead of the intended behavior.
Bug Description
In
flow/retriever/router/router.go, theNewRetrieverfunction builds a default router function whenconfig.Routerisnil, but then accidentally storesconfig.Router(which is stillnil) into therouterRetrieverstruct instead of the localroutervariable. This causes a nil pointer dereference panic whenRetrieve()is called without a customRouterconfigured.Affected File
flow/retriever/router/router.goRoot Cause
When
config.Routerisnil(the common case where the user relies on the default all-retrievers router), the struct fieldrouterRetriever.routeris alsonil. TheRetrieve()method then callse.router(routeCtx, query), which panics with a nil pointer dereference.Steps to Reproduce
Expected Behavior
NewRetrievershould store the resolved (possibly default)routervariable into the struct, notconfig.Router. Whenconfig.Routerisnil, all registered retrievers should be queried (the intended default behavior).Fix
Change line in
NewRetriever:Impact
Any caller that omits
Config.Router(relying on the documented default behavior of querying all retrievers) will encounter a nil pointer dereference panic at runtime instead of the intended behavior.