caddyhttp: use errors.AsType for request body limit errors (#8090)

With the Go 1.26 floor, golangci-lint's modernize analyzer (errorsastype) flags the three errors.As calls that look for RequestBodyLimitError, which turned the Lint workflow red on master after #8056. Replace them with the generic errors.AsType; behavior is unchanged. Assistance disclosure: this change was made by an AI agent (Claude Sonnet 5.5, model ID claude-sonnet-5-5) acting as Matthew Holt's agent and under his approval. Build, go vet and the caddyhttp and caddyhttp/templates tests pass locally; golangci-lint itself was not run locally. Co-authored-by: Claude Code <noreply@anthropic.com>

Matt Holt committed Sep 30, 2026 at 13:50 UTC 0a137e2fafc3c3fffcd2f27c8ef0a78913165902

2 files changed +3 -6

modules/caddyhttp/templates/tplcontext.go

+1 -2

@@ -268,8 +268,7 @@ func (c TemplateContext) funcPlaceholder(name string) (string, error) {

268 // server renders the 413, and any other value, including unrelated

269 // errors, is converted to a string as before

270 if err, ok := value.(error); ok {

271 - var bodyLimit caddyhttp.RequestBodyLimitError

272 - if errors.As(err, &bodyLimit) {

271 + if bodyLimit, ok := errors.AsType[caddyhttp.RequestBodyLimitError](err); ok {

272 return "", caddyhttp.HandlerError{Err: bodyLimit, StatusCode: bodyLimit.StatusCode()}

273 }

274 }

modules/caddyhttp/vars.go

+2 -4

@@ -203,8 +203,7 @@ func (m VarsMatcher) MatchWithError(r *http.Request) (bool, error) {

203 // request_body max_size limit when {http.request.body} is

204 // truncated) instead of matching on its error text; unrelated

205 // errors are matched on their text as before

206 - var bodyLimit RequestBodyLimitError

207 - if errors.As(vv, &bodyLimit) {

206 + if bodyLimit, ok := errors.AsType[RequestBodyLimitError](vv); ok {

207 // wrap in a status-carrying handler error so the server

208 // renders the 413

209 return false, HandlerError{Err: bodyLimit, StatusCode: bodyLimit.StatusCode()}

@@ -350,8 +349,7 @@ func (m MatchVarsRE) MatchWithError(r *http.Request) (bool, error) {

349 // request_body max_size limit when {http.request.body} is

350 // truncated) instead of matching on its error text; unrelated

351 // errors are matched on their text as before

353 - var bodyLimit RequestBodyLimitError

354 - if errors.As(vv, &bodyLimit) {

352 + if bodyLimit, ok := errors.AsType[RequestBodyLimitError](vv); ok {

353 // wrap in a status-carrying handler error so the server

354 // renders the 413

355 return false, HandlerError{Err: bodyLimit, StatusCode: bodyLimit.StatusCode()}