Match the forge's 404 by its status, not by digits a path's sha may hold (issue 1845)

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/forge.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"regexp"
 	"strings"
 
 	"mesh-delivery-checker/internal/check"
@@ -18,6 +19,9 @@ const (
 	commitsTool = "gitea.gitea_commits"
 )
 
+// notFoundStatus is the 404 of the forge's error, `Gitea API <path>: <status> <body>`.
+var notFoundStatus = regexp.MustCompile(`: 404( |$)`)
+
 // forgeReads reads the forge through call (mesh-sdk process.Conn.Call as the checker's own account).
 type forgeReads struct {
 	call func(key string, body any) (json.RawMessage, error)
@@ -33,8 +37,9 @@ func (f forgeReads) File(_ context.Context, repository, path, ref string) (strin
 	owner, repo := ownerRepo(repository)
 	raw, err := f.call(getFileTool, map[string]string{"owner": owner, "repo": repo, "path": path, "ref": ref})
 	if err != nil {
-		if strings.Contains(err.Error(), "404") {
-			// The forge answers 404 for a file the ref does not hold (issue 1845).
+		if notFoundStatus.MatchString(err.Error()) {
+			// The forge answers 404 for a file the ref does not hold (issue 1845). The status is matched in its own place,
+			// after the path's colon: the path carries a sha that may hold the digits 404.
 			return "", fmt.Errorf("%w: %v", check.ErrNotFound, err)
 		}
 		return "", err

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/forge_test.go

@@ -79,7 +79,9 @@ func TestAFileTheRefDoesNotHoldIsNotFoundAndOtherFailuresAreNot(t *testing.T) {
 	if _, err := f.File(context.Background(), "novox/mesh-catalog", "checks/particulars/go.mod", "98ca97fc"); !errors.Is(err, check.ErrNotFound) {
 		t.Errorf("a 404 is %v, want ErrNotFound", err)
 	}
-	f = forgeReads{call: func(string, any) (json.RawMessage, error) { return nil, errors.New("Gitea API: 500 internal error") }}
+	f = forgeReads{call: func(string, any) (json.RawMessage, error) {
+		return nil, errors.New("Gitea API contents/go.mod?ref=1111111111111111111111111111111404abcde: 500 internal error")
+	}}
 	if _, err := f.File(context.Background(), "novox/mesh-catalog", "go.mod", "main"); err == nil || errors.Is(err, check.ErrNotFound) {
 		t.Errorf("a 500 is %v, want a failure that is not ErrNotFound", err)
 	}