From d88faafb2f706d6bed7ef921c87da7947b74fa85 Mon Sep 17 00:00:00 2001
From: Shuntaro Takahashi <shuntaro-takahashi@m3.com>
Date: Mon, 18 May 2026 17:48:50 +0900
Subject: [PATCH] fix: restore errors.Is for flag.ErrHelp regressed by JSON-RPC
 merge
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#3736 changed `err == flag.ErrHelp` to `errors.Is(err, flag.ErrHelp)` in
`codegen/example/templates/client_endpoint_init.go.tpl` so the generated
example client passes `golangci-lint` with `errorlint` enabled.

That fix was later overwritten by #3734 (Add JSON-RPC 2.0 Transport
Support, commit 8931cbb), which appears to have rebased on a pre-#3736
state and silently reverted the line back to `err == flag.ErrHelp`.

This commit restores the `errors.Is` form and updates the affected
golden testdata files. No other source change is required — the
`errors` package is already in the import spec list for the generated
file (`codegen/example/example_client.go:41`).
---
 codegen/example/templates/client_endpoint_init.go.tpl           | 2 +-
 codegen/example/testdata/client-no-server.golden                | 2 +-
 .../client-single-server-multiple-hosts-with-variables.golden   | 2 +-
 .../example/testdata/client-single-server-multiple-hosts.golden | 2 +-
 .../client-single-server-single-host-with-variables.golden      | 2 +-
 .../example/testdata/client-single-server-single-host.golden    | 2 +-
 6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/codegen/example/templates/client_endpoint_init.go.tpl b/codegen/example/templates/client_endpoint_init.go.tpl
index e5ae63d491..02353b8c76 100644
--- a/codegen/example/templates/client_endpoint_init.go.tpl
+++ b/codegen/example/templates/client_endpoint_init.go.tpl
@@ -31,7 +31,7 @@
 		}
 	}
 	if err != nil {
-		if err == flag.ErrHelp {
+		if errors.Is(err, flag.ErrHelp) {
 			os.Exit(0)
 		}
 		fmt.Fprintln(os.Stderr, err.Error())
diff --git a/codegen/example/testdata/client-no-server.golden b/codegen/example/testdata/client-no-server.golden
index 938a380cab..4bed82edee 100644
--- a/codegen/example/testdata/client-no-server.golden
+++ b/codegen/example/testdata/client-no-server.golden
@@ -61,7 +61,7 @@ func main() {
 		}
 	}
 	if err != nil {
-		if err == flag.ErrHelp {
+		if errors.Is(err, flag.ErrHelp) {
 			os.Exit(0)
 		}
 		fmt.Fprintln(os.Stderr, err.Error())
diff --git a/codegen/example/testdata/client-single-server-multiple-hosts-with-variables.golden b/codegen/example/testdata/client-single-server-multiple-hosts-with-variables.golden
index b36af674e6..bb0df699fc 100644
--- a/codegen/example/testdata/client-single-server-multiple-hosts-with-variables.golden
+++ b/codegen/example/testdata/client-single-server-multiple-hosts-with-variables.golden
@@ -80,7 +80,7 @@ func main() {
 		}
 	}
 	if err != nil {
-		if err == flag.ErrHelp {
+		if errors.Is(err, flag.ErrHelp) {
 			os.Exit(0)
 		}
 		fmt.Fprintln(os.Stderr, err.Error())
diff --git a/codegen/example/testdata/client-single-server-multiple-hosts.golden b/codegen/example/testdata/client-single-server-multiple-hosts.golden
index 0e6730a575..efb2085ef0 100644
--- a/codegen/example/testdata/client-single-server-multiple-hosts.golden
+++ b/codegen/example/testdata/client-single-server-multiple-hosts.golden
@@ -61,7 +61,7 @@ func main() {
 		}
 	}
 	if err != nil {
-		if err == flag.ErrHelp {
+		if errors.Is(err, flag.ErrHelp) {
 			os.Exit(0)
 		}
 		fmt.Fprintln(os.Stderr, err.Error())
diff --git a/codegen/example/testdata/client-single-server-single-host-with-variables.golden b/codegen/example/testdata/client-single-server-single-host-with-variables.golden
index 060a82e459..4fd6755bc6 100644
--- a/codegen/example/testdata/client-single-server-single-host-with-variables.golden
+++ b/codegen/example/testdata/client-single-server-single-host-with-variables.golden
@@ -77,7 +77,7 @@ func main() {
 		}
 	}
 	if err != nil {
-		if err == flag.ErrHelp {
+		if errors.Is(err, flag.ErrHelp) {
 			os.Exit(0)
 		}
 		fmt.Fprintln(os.Stderr, err.Error())
diff --git a/codegen/example/testdata/client-single-server-single-host.golden b/codegen/example/testdata/client-single-server-single-host.golden
index f6b0fc4520..fadb54b2b9 100644
--- a/codegen/example/testdata/client-single-server-single-host.golden
+++ b/codegen/example/testdata/client-single-server-single-host.golden
@@ -61,7 +61,7 @@ func main() {
 		}
 	}
 	if err != nil {
-		if err == flag.ErrHelp {
+		if errors.Is(err, flag.ErrHelp) {
 			os.Exit(0)
 		}
 		fmt.Fprintln(os.Stderr, err.Error())