fix: improve error handling for GitHub fetch failures and adjust issu…

backend/spi_api.go

@@ -2,12 +2,14 @@ package main
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/url"
 	"strconv"
 	"strings"
 	"time"
 
+	plugin "github.com/Paca-AI/plugin-sdk-go"
 	gp "github.com/Paca-AI/plugin-sdk-go/gitprovider"
 )
 
@@ -67,7 +69,7 @@ func (a *ghAPI) doRaw(method, path string, body any, accept string) (int, string
 	}
 	resp, err := fetch(method, rawURL, h, payload)
 	if err != nil {
-		return 0, "", nil, gp.Errorf(gp.CodeTransient, "GitHub is unreachable")
+		return 0, "", nil, fetchFailure(err)
 	}
 	if resp.Status == 401 && a.refresh != nil {
 		refresh := a.refresh
@@ -81,7 +83,7 @@ func (a *ghAPI) doRaw(method, path string, body any, accept string) (int, string
 		a.token = tok
 		h["Authorization"] = "Bearer " + tok
 		if resp, err = fetch(method, rawURL, h, payload); err != nil {
-			return 0, "", nil, gp.Errorf(gp.CodeTransient, "GitHub is unreachable")
+			return 0, "", nil, fetchFailure(err)
 		}
 	}
 	if resp.Status >= 400 {
@@ -90,6 +92,16 @@ func (a *ghAPI) doRaw(method, path string, body any, accept string) (int, string
 	return resp.Status, resp.Body, resp.Headers, nil
 }
 
+// fetchFailure maps a failed host fetch to a *gp.Error. A response too large
+// for the plugin to receive is a size problem, not an outage, so it must not
+// be reported (or retried) as "GitHub is unreachable".
+func fetchFailure(err error) error {
+	if errors.Is(err, plugin.ErrResponseTooLarge) {
+		return gp.Errorf(gp.CodeInternal, "GitHub's response was too large for the plugin to receive")
+	}
+	return gp.Errorf(gp.CodeTransient, "GitHub is unreachable")
+}
+
 func (a *ghAPI) get(path string, out any) error {
 	text, err := a.do("GET", path, nil, "")
 	if err != nil {

backend/spi_issues_test.go

@@ -2,7 +2,10 @@ package main
 
 import (
 	"encoding/json"
+	"errors"
+	"fmt"
 	"net/url"
+	"strings"
 	"testing"
 
 	plugin "github.com/Paca-AI/plugin-sdk-go"
@@ -11,6 +14,16 @@ import (
 
 func TestListIssuesFiltersPullRequestsWithoutLosingPages(t *testing.T) {
 	p, g, _ := seededProvider(t)
+	// Page 1 is a full page (100 rows) holding a single real issue among pull
+	// requests; page 2 is short, so it is the last.
+	fullPage := func() []map[string]any {
+		rows := make([]map[string]any, listPerPage)
+		for i := range rows {
+			rows[i] = map[string]any{"number": i + 1, "pull_request": map[string]any{"url": "x"}}
+		}
+		rows[0] = map[string]any{"number": 101, "title": "Bug", "body": "Details", "state": "closed", "html_url": "https://github.com/acme/web/issues/101", "user": map[string]string{"login": "alice"}, "labels": []map[string]string{{"name": "bug"}}, "assignees": []map[string]string{{"login": "bob"}}}
+		return rows
+	}
 	fetch = func(method, rawURL string, headers map[string]string, body string) (*plugin.FetchResponse, error) {
 		u, err := url.Parse(rawURL)
 		if err != nil {
@@ -19,39 +32,56 @@ func TestListIssuesFiltersPullRequestsWithoutLosingPages(t *testing.T) {
 		if u.Path != "/repos/acme/web/issues" {
 			return g.fetch(method, rawURL, headers, body)
 		}
-		if method != "GET" || u.Query().Get("state") != "closed" || u.Query().Get("per_page") != "1" {
+		if method != "GET" || u.Query().Get("state") != "closed" || u.Query().Get("per_page") != "100" {
 			t.Fatalf("unexpected request: %s %s", method, rawURL)
 		}
 		switch u.Query().Get("page") {
 		case "1":
-			return resp(200, []map[string]any{{"number": 1, "pull_request": map[string]any{"url": "x"}}})
+			return resp(200, fullPage())
 		case "2":
-			return resp(200, []map[string]any{{"number": 101, "title": "Bug", "body": "Details", "state": "closed", "html_url": "https://github.com/acme/web/issues/101", "user": map[string]string{"login": "alice"}, "labels": []map[string]string{{"name": "bug"}}, "assignees": []map[string]string{{"login": "bob"}}}})
-		case "3":
-			return resp(200, []map[string]any{})
+			return resp(200, []map[string]any{{"number": 202, "pull_request": map[string]any{"url": "x"}}})
 		default:
 			t.Fatalf("unexpected page: %s", rawURL)
 			return nil, nil
 		}
 	}
 	first, err := p.ListIssues(bg, gp.ListIssuesRequest{Target: webTarget(), State: "closed"})
-	if err != nil || len(first.Items) != 0 || first.NextCursor != "2" {
+	if err != nil || len(first.Items) != 1 || first.NextCursor != "2" {
 		t.Fatalf("first page: %+v, %v", first, err)
 	}
 	second, err := p.ListIssues(bg, gp.ListIssuesRequest{Target: webTarget(), State: "closed", Cursor: first.NextCursor})
-	if err != nil || len(second.Items) != 1 || second.NextCursor != "3" {
+	if err != nil || len(second.Items) != 0 || second.NextCursor != "" {
 		t.Fatalf("second page: %+v, %v", second, err)
 	}
-	third, err := p.ListIssues(bg, gp.ListIssuesRequest{Target: webTarget(), State: "closed", Cursor: second.NextCursor})
-	if err != nil || len(third.Items) != 0 || third.NextCursor != "" {
-		t.Fatalf("third page: %+v, %v", third, err)
-	}
-	i := second.Items[0]
+	i := first.Items[0]
 	if i.Number != "101" || i.Title != "Bug" || i.Body != "Details" || i.State != "closed" || i.Author != "alice" || i.URL != "https://github.com/acme/web/issues/101" || len(i.Labels) != 1 || i.Labels[0] != "bug" || len(i.Assignees) != 1 || i.Assignees[0] != "bob" {
 		t.Fatalf("issue fields: %+v", i)
 	}
 }
 
+// A response the SDK could not deliver is a size problem; it must not be
+// reported as GitHub being unreachable (which core would treat as retryable).
+func TestFetchTooLargeIsNotReportedAsUnreachable(t *testing.T) {
+	p, g, _ := seededProvider(t)
+	fetch = func(method, rawURL string, headers map[string]string, body string) (*plugin.FetchResponse, error) {
+		if u, _ := url.Parse(rawURL); u.Path == "/repos/acme/web/issues" {
+			return nil, fmt.Errorf("plugin: fetch: %w: too big", plugin.ErrResponseTooLarge)
+		}
+		return g.fetch(method, rawURL, headers, body)
+	}
+	_, err := p.ListIssues(bg, gp.ListIssuesRequest{Target: webTarget()})
+	if codeOf(t, err) != gp.CodeInternal || strings.Contains(err.Error(), "unreachable") {
+		t.Fatalf("want a non-retryable size error, got: %v", err)
+	}
+	fetch = func(string, string, map[string]string, string) (*plugin.FetchResponse, error) {
+		return nil, errors.New("dial failed")
+	}
+	_, err = p.ListIssues(bg, gp.ListIssuesRequest{Target: webTarget()})
+	if codeOf(t, err) != gp.CodeTransient {
+		t.Fatalf("a genuine transport failure stays transient, got: %v", err)
+	}
+}
+
 func TestListIssuesValidatesAndPropagatesErrors(t *testing.T) {
 	p, g, _ := seededProvider(t)
 	for _, req := range []gp.ListIssuesRequest{

backend/spi_reads.go

@@ -419,14 +419,12 @@ func (p *ghProvider) ListIssues(_ context.Context, req gp.ListIssuesRequest) (gp
 		return gp.IssuePage{}, err
 	}
 	var issues []ghIssue
-	// shortcut: one large response can still exceed the WASM arena; upgrade the SDK transport limit handling.
-	if err := api.get(repo+"/issues?state="+state+"&per_page=1&page="+strconv.Itoa(pg), &issues); err != nil {
+	if err := api.get(repo+"/issues?state="+state+"&per_page="+strconv.Itoa(listPerPage)+"&page="+strconv.Itoa(pg), &issues); err != nil {
 		return gp.IssuePage{}, err
 	}
-	out := gp.IssuePage{Items: []gp.Issue{}}
-	if len(issues) > 0 {
-		out.NextCursor = strconv.Itoa(pg + 1)
-	}
+	// GitHub's issues endpoint also returns pull requests, so the cursor must
+	// follow the raw page size, not the filtered item count.
+	out := gp.IssuePage{Items: []gp.Issue{}, NextCursor: nextPage(len(issues), pg)}
 	for _, issue := range issues {
 		if len(issue.PullRequest) == 0 || string(issue.PullRequest) == "null" {
 			out.Items = append(out.Items, issue.toIssue())