fix: don't drop handlers that collide with a Mount()/Route() pattern by VojtechVitek · Pull Request #1148 · go-chi/chi

VojtechVitek · 2026-08-09T16:42:19Z

Fixes #830: a handler sharing a pattern with a Route()/Mount() call was invisible to Walk()/Routes(), because the mount's internal stub handler caused the whole node to be hidden.

r.Route("/foo", func(r chi.Router) {
    r.Route("/bar", func(r chi.Router) { r.Get("/{id}", h) })
    r.Get("/bar", h) // routable, but invisible to Walk
})

Builds on #1146 (thanks @deepakganesh78 for the diagnosis, repro, and the sameHandler idea), with two corrections found by testing Routes() directly instead of only Walk:

Only hides the stub's "*" slot on leaf nodes — subroute nodes still need it, since walk() reads Handlers["*"] to pick up With() middleware from a *ChainHandler. Fix Walk for routes with handlers and subrouters #1146 hides it everywhere, which leaks two extra Route entries per Mount()/Route() call.
Drops Fix Walk for routes with handlers and subrouters #1146's unrelated walk() change (continue/subrouteMw) — reverting just that half still passes everything.

Also adds a regression test for #750 (middlewares on a Group() not reaching a Route() mounted inside it) — already fixed on master, this just locks it in.

Credits — reported, diagnosed, or attempted a fix on these two issues:

chi.Walk missing routes #830: @sauerbraten (reported), @ganicus, @lai0xn, @deepakganesh78 (Fix Walk for routes with handlers and subrouters #1146)
chi.Walk missing middlewares #750: @ebabani (reported), @pkieltyka, @ganicus

Testing: TestWalkRouteWithHandlerAndSubrouter, TestRoutesHidesMountStub, TestWalkMiddlewaresAcrossGroupAndRoute; go build/vet/gofmt -l/test ./... all clean.

Mount() (and Route(), which is sugar for it) registers a synthetic "stub" handler on its exact mount pattern to connect it to the subrouter. node.routes() used that stub as a signal to hide the whole node from Routes()/Walk() — but if a real handler was also registered on that same pattern (e.g. r.Get("/bar", h) next to r.Route("/bar", ...)), it got hidden too, even though the route is perfectly routable. routes() now compares each handler against the stub by identity (sameHandler, using reflection since http.HandlerFunc isn't == comparable) and only hides the stub itself, keeping any real handler that shares the node. The "*" slot is only filtered on leaf nodes, since Walk() also reads Handlers["*"] to detect a *ChainHandler and propagate With() middleware into a subrouter — that entry has to survive even when it's the same value as the stub. Fixes #830. Also adds a regression test for #750 (middlewares registered on a Group not reaching handlers on a Route() mounted inside it), which turns out to already be fixed on master — this just locks it in.

Chan, Pointer, and UnsafePointer are already == comparable in Go — only Func, Map, and Slice aren't, and Map/Slice identity was never a real case here (the stub is always http.HandlerFunc or *ChainHandler).

…desMountStub

VojtechVitek

LGTM

@giortzisg

VojtechVitek mentioned this pull request Aug 9, 2026

Fix Walk for routes with handlers and subrouters #1146

Closed

VojtechVitek added 4 commits August 10, 2026 10:35

Trim comments in routes() to just the why

7ff59a3

Rename sameHandler to equalHandlers; narrow the reflect switch to Func

b088fe4

Chan, Pointer, and UnsafePointer are already == comparable in Go — only Func, Map, and Slice aren't, and Map/Slice identity was never a real case here (the stub is always http.HandlerFunc or *ChainHandler).

Explain why Routes() reports /api/* and not /api/{id} in TestRoutesHi…

f8b69fa

…desMountStub

Trim comment in TestRoutesHidesMountStub

0281853

VojtechVitek mentioned this pull request Aug 10, 2026

Design: convenience for a flattened, fully-qualified route listing #1149

Closed

VojtechVitek commented Aug 10, 2026

View reviewed changes

Comment thread tree_test.go

This was referenced Aug 10, 2026

chi.Walk missing middlewares #750

Closed

chi.Walk missing routes #830

Closed

VojtechVitek merged commit 29164f0 into master Aug 20, 2026
16 checks passed

VojtechVitek deleted the fix/walk-routes-mount-stub-leak branch August 20, 2026 08:55

sk-sanjay01 mentioned this pull request Aug 26, 2026

fix: panic on Mount() when a router is mounted onto itself #1159

Merged

vtmocanu mentioned this pull request Aug 28, 2026

fix(deps): update go-chi/chi/v5 to v5.3.2 vtmocanu/uzi#741

Merged

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fix: don't drop handlers that collide with a Mount()/Route() pattern - #1148

fix: don't drop handlers that collide with a Mount()/Route() pattern#1148
VojtechVitek merged 5 commits into
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fix/walk-routes-mount-stub-leak

VojtechVitek commented Aug 9, 2026 •

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VojtechVitek commented Aug 9, 2026 •

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