fix(provider): keep /v4 base from getting a spurious /v1 chat path

The OpenAI-compatible client only treated a base URL ending in "/v1" as
already-versioned; any other base got "/v1/chat/completions" appended.

Z.AI's coding-plan base ends in "/paas/v4", so requests were sent to
".../paas/v4/v1/chat/completions" — a path that does not exist — and
every GLM model returned 404.

Match any trailing "/vN" version segment instead. This is behaviour-
identical for all existing providers (their versioned bases all end in
"/v1") and only changes Z.AI, which now hits ".../paas/v4/chat/completions".

commit: 9bb884ebbc8901df981d7d74087091ec0a20f952
author: Pietro Di Bello · 4mo ago · 2026-06-14 19:45 UTC
parent: 85a3c3b
signature: GPG Unverified4F1F41D0C6F3B477 The key is unknown

2 files · +62 -5

M packages/provider/openai.go +22 -5


@@ -8,12 +8,32 @@ import (
8	8		"fmt"
9	9		"io"
10	10		"net/http"
	11	+	"regexp"
11	12		"strings"
12	13		"time"
13	14		)
14	15
15	16		const openaiDefaultBaseURL = "https://api.openai.com"
16	17
	18	+	// versionSegmentSuffix matches a trailing API version segment such as
	19	+	// "/v1" or Z.AI's "/v4".
	20	+	var versionSegmentSuffix = regexp.MustCompile(`/v\d+$`)
	21	+
	22	+	// chatCompletionsURL builds the chat-completions endpoint for an
	23	+	// OpenAI-compatible base URL. A base that already carries an API
	24	+	// version segment gets "/chat/completions" appended directly; a bare
	25	+	// host (e.g. api.openai.com) gets the conventional "/v1/chat/completions".
	26	+	//
	27	+	// Matching any "/vN" segment (not just "/v1") keeps Z.AI's coding-plan
	28	+	// base, which ends in "/paas/v4", from getting a spurious "/v1" that
	29	+	// yields ".../paas/v4/v1/chat/completions" and a 404.
	30	+	func chatCompletionsURL(baseURL string) string {
	31	+	if versionSegmentSuffix.MatchString(baseURL) {
	32	+	return baseURL + "/chat/completions"
	33	+	}
	34	+	return baseURL + "/v1/chat/completions"
	35	+	}
	36	+
17	37		type openaiClient struct {
18	38		apiKey string
19	39		baseURL string

@@ -412,10 +432,7 @@ func buildOAIContentBlocks(blocks []Content, isError bool) []interface{} {
412	432		// ---- streaming ----
413	433
414	434		func (c *openaiClient) Stream(ctx context.Context, req Request) (<-chan Event, error) {
415		-	apiPath := "/v1/chat/completions"
416		-	if strings.HasSuffix(c.baseURL, "/v1") {
417		-	apiPath = "/chat/completions"
418		-	}
	435	+	endpoint := chatCompletionsURL(c.baseURL)
419	436		wire, err := c.buildRequest(req)
420	437		if err != nil {
421	438		return nil, err

@@ -425,7 +442,7 @@ func (c *openaiClient) Stream(ctx context.Context, req Request) (<-chan Event, e
425	442		return nil, err
426	443		}
427	444		newReq := func() (*http.Request, error) {
428		-	httpReq, err := http.NewRequestWithContext(ctx, "POST", c.baseURL+apiPath, bytes.NewReader(body))
	445	+	httpReq, err := http.NewRequestWithContext(ctx, "POST", endpoint, bytes.NewReader(body))
429	446		if err != nil {
430	447		return nil, err
431	448		}

 	"fmt"
 	"io"
 	"net/http"
+	"regexp"
 	"strings"
 	"time"
 )
 const openaiDefaultBaseURL = "https://api.openai.com"
+// versionSegmentSuffix matches a trailing API version segment such as
+// "/v1" or Z.AI's "/v4".
+var versionSegmentSuffix = regexp.MustCompile(`/v\d+$`)
+// chatCompletionsURL builds the chat-completions endpoint for an
+// OpenAI-compatible base URL. A base that already carries an API
+// version segment gets "/chat/completions" appended directly; a bare
+// host (e.g. api.openai.com) gets the conventional "/v1/chat/completions".
+//
+// Matching any "/vN" segment (not just "/v1") keeps Z.AI's coding-plan
+// base, which ends in "/paas/v4", from getting a spurious "/v1" that
+// yields ".../paas/v4/v1/chat/completions" and a 404.
+func chatCompletionsURL(baseURL string) string {
+	if versionSegmentSuffix.MatchString(baseURL) {
+		return baseURL + "/chat/completions"
+	}
+	return baseURL + "/v1/chat/completions"
+}
 type openaiClient struct {
 	apiKey  string
 	baseURL string
 // ---- streaming ----
 func (c *openaiClient) Stream(ctx context.Context, req Request) (<-chan Event, error) {
-	apiPath := "/v1/chat/completions"
+	endpoint := chatCompletionsURL(c.baseURL)
-	if strings.HasSuffix(c.baseURL, "/v1") {
-		apiPath = "/chat/completions"
-	}
 	wire, err := c.buildRequest(req)
 	if err != nil {
 		return nil, err
 		return nil, err
 	}
 	newReq := func() (*http.Request, error) {
-		httpReq, err := http.NewRequestWithContext(ctx, "POST", c.baseURL+apiPath, bytes.NewReader(body))
+		httpReq, err := http.NewRequestWithContext(ctx, "POST", endpoint, bytes.NewReader(body))
 		if err != nil {
 			return nil, err
 		}

A packages/provider/openai_url_test.go +40 -0

@@ -0,0 +1,40 @@
	1	+	package provider
	2	+
	3	+	import "testing"
	4	+
	5	+	// TestChatCompletionsURL pins the endpoint built for OpenAI-compatible
	6	+	// providers. The regression that motivated it: Z.AI's coding-plan base
	7	+	// carries a "/v4" version segment, so blindly appending
	8	+	// "/v1/chat/completions" produced ".../paas/v4/v1/chat/completions"
	9	+	// and a 404. Any base that already ends in a version segment must get
	10	+	// "/chat/completions" appended directly.
	11	+	func TestChatCompletionsURL(t *testing.T) {
	12	+	cases := []struct {
	13	+	name string
	14	+	baseURL string
	15	+	want string
	16	+	}{
	17	+	{
	18	+	name: "bare host gets conventional /v1 path",
	19	+	baseURL: "https://api.openai.com",
	20	+	want: "https://api.openai.com/v1/chat/completions",
	21	+	},
	22	+	{
	23	+	name: "v1 base is not doubled",
	24	+	baseURL: "https://api.moonshot.ai/v1",
	25	+	want: "https://api.moonshot.ai/v1/chat/completions",
	26	+	},
	27	+	{
	28	+	name: "zai coding plan v4 base is not given a spurious /v1",
	29	+	baseURL: "https://api.z.ai/api/coding/paas/v4",
	30	+	want: "https://api.z.ai/api/coding/paas/v4/chat/completions",
	31	+	},
	32	+	}
	33	+	for _, tc := range cases {
	34	+	t.Run(tc.name, func(t *testing.T) {
	35	+	if got := chatCompletionsURL(tc.baseURL); got != tc.want {
	36	+	t.Errorf("chatCompletionsURL(%q) = %q, want %q", tc.baseURL, got, tc.want)
	37	+	}
	38	+	})
	39	+	}
	40	+	}

@@ -0,0 +1,40 @@
	1	+	package provider
	2	+
	3	+	import "testing"
	4	+
	5	+	// TestChatCompletionsURL pins the endpoint built for OpenAI-compatible
	6	+	// providers. The regression that motivated it: Z.AI's coding-plan base
	7	+	// carries a "/v4" version segment, so blindly appending
	8	+	// "/v1/chat/completions" produced ".../paas/v4/v1/chat/completions"
	9	+	// and a 404. Any base that already ends in a version segment must get
	10	+	// "/chat/completions" appended directly.
	11	+	func TestChatCompletionsURL(t *testing.T) {
	12	+	cases := []struct {
	13	+	name string
	14	+	baseURL string
	15	+	want string
	16	+	}{
	17	+	{
	18	+	name: "bare host gets conventional /v1 path",
	19	+	baseURL: "https://api.openai.com",
	20	+	want: "https://api.openai.com/v1/chat/completions",
	21	+	},
	22	+	{
	23	+	name: "v1 base is not doubled",
	24	+	baseURL: "https://api.moonshot.ai/v1",
	25	+	want: "https://api.moonshot.ai/v1/chat/completions",
	26	+	},
	27	+	{
	28	+	name: "zai coding plan v4 base is not given a spurious /v1",
	29	+	baseURL: "https://api.z.ai/api/coding/paas/v4",
	30	+	want: "https://api.z.ai/api/coding/paas/v4/chat/completions",
	31	+	},
	32	+	}
	33	+	for _, tc := range cases {
	34	+	t.Run(tc.name, func(t *testing.T) {
	35	+	if got := chatCompletionsURL(tc.baseURL); got != tc.want {
	36	+	t.Errorf("chatCompletionsURL(%q) = %q, want %q", tc.baseURL, got, tc.want)
	37	+	}
	38	+	})
	39	+	}
	40	+	}