Make the forge's tools act as an account of their own, not the administrator (issue 469, ADR 0365 clause 2)

The tools' token reached everything the administrator may do, so their boundary rested on their own guards.
The gitea module now makes a plain account, mesh-tools, with the admin login, gives it write on code, issues
and pull requests of every novox repository through one team, and mints the tools' token for it; the admin's
old token goes only after the new one is kept. The Go forge bundle sends that token, never the admin login.
The forge shows protection rules only to a repository administrator, so every check reads a branch's
protection from the branch. mesh-admin stays a ready author, so marks made before the move keep counting.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

modules/gitea/cmd/forge/account_test.go

@@ -0,0 +1,120 @@
+package main
+
+// The commit and the reads act as the tools' own account (novox/hq ADR 0365 §2, issue 469): the token the module
+// keeps for `mesh-tools`, never the admin login. That account is no repository's administrator, so the forge
+// refuses it the protection rules (403, as gitea's reqAdmin does); the commit then judges an existing branch by the
+// protection the forge says it applies, and leaves a branch not made yet to the forge's own judgement.
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"gitea/internal/forgehttp"
+)
+
+const toolsToken = "tools-token-never-shown"
+
+// asTools serves the fake forge to a bundle holding the tools' token: only that token is taken, the rules are
+// refused as to a non-administrator, and the branches named protected say so as the forge does.
+func asTools(t *testing.T, f *fakeForge, protected map[string]string, scopes string) (*Forge, *[]string) {
+	dir := t.TempDir()
+	file := filepath.Join(dir, "token")
+	if err := os.WriteFile(file, []byte(toolsToken+"\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(file+".scopes", []byte(scopes+"\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	var seen []string
+	const repo = "/api/v1/repos/acme/app"
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		seen = append(seen, r.Method+" "+r.URL.Path)
+		if _, _, basic := r.BasicAuth(); basic || r.Header.Get("Authorization") != "token "+toolsToken {
+			http.Error(w, "unauthorized", 401)
+			return
+		}
+		if r.URL.Path == repo+"/branch_protections" {
+			http.Error(w, `{"message":"token does not have the administration of this repository"}`, 403)
+			return
+		}
+		if name := strings.TrimPrefix(r.URL.Path, repo+"/branches/"); r.Method == "GET" && name != r.URL.Path {
+			if rule, ok := protected[name]; ok {
+				_, _ = w.Write([]byte(`{"name":"` + name + `","commit":{"id":"c0"},"protected":true,"effective_branch_protection_name":"` + rule + `"}`))
+				return
+			}
+		}
+		r.SetBasicAuth("mesh-admin", f.password) // the fake's own door, past the token checked above
+		f.handle(w, r)
+	}))
+	t.Cleanup(srv.Close)
+	return &Forge{Client: forgehttp.Client{URL: srv.URL, TokenFile: file, Account: "mesh-tools"}}, &seen
+}
+
+func TestTheToolsAccountCommitsOnANewBranchWithItsTokenThoughTheRulesAreNotItsToRead(t *testing.T) {
+	f := newFake(t)
+	forge, _ := asTools(t, f, nil, "read:user,write:issue,write:repository for mesh-tools")
+	got, err := commit(context.Background(), forge, ask(t, map[string]any{"branch": "fix/365",
+		"files": filesArg(map[string]any{"path": "x", "content": "x"})}))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(f.writes) != 1 || !got.Created {
+		t.Fatalf("%d writes, %+v", len(f.writes), got)
+	}
+}
+
+func TestTheToolsAccountIsRefusedAProtectedBranchTheForgeSaysItGuardsAndTheDefaultBranch(t *testing.T) {
+	for branch, rule := range map[string]string{"release/1.0": "release/*", "fix/1-old": "fix/1-old", "main": ""} {
+		f := newFake(t)
+		protected := map[string]string{}
+		if rule != "" {
+			protected[branch] = rule
+		}
+		forge, _ := asTools(t, f, protected, "read:user,write:issue,write:repository for mesh-tools")
+		_, err := commit(context.Background(), forge, ask(t, map[string]any{"branch": branch,
+			"files": filesArg(map[string]any{"path": "x", "content": "x"})}))
+		if err == nil || !strings.Contains(err.Error(), "refused") || !strings.Contains(err.Error(), "ADR 0266") {
+			t.Errorf("%s: %v", branch, err)
+		}
+		if rule != "" && !strings.Contains(err.Error(), rule) {
+			t.Errorf("%s: the rule %s is not named: %v", branch, rule, err)
+		}
+		if len(f.writes)+len(f.patches) != 0 {
+			t.Errorf("%s: something was written", branch)
+		}
+	}
+}
+
+func TestATokenKeptForTheAdministratorIsNeverSent(t *testing.T) {
+	f := newFake(t)
+	// What the module kept before ADR 0365: the admin's token, its scopes line naming no account.
+	forge, seen := asTools(t, f, nil, "read:user,write:issue,write:repository")
+	_, err := commit(context.Background(), forge, ask(t, map[string]any{"branch": "fix/365",
+		"files": filesArg(map[string]any{"path": "x", "content": "x"})}))
+	if err == nil || !strings.Contains(err.Error(), "not mesh-tools's") {
+		t.Fatalf("%v", err)
+	}
+	if len(*seen) != 0 {
+		t.Fatalf("the forge was asked %v", *seen)
+	}
+}
+
+func TestTheBundleHandedATokenFileNeedsNoAdminLogin(t *testing.T) {
+	t.Setenv("MESH_GITEA_URL", "http://127.0.0.1:3000")
+	t.Setenv("MESH_GITEA_TOKEN_FILE", "/state/token")
+	t.Setenv("MESH_GITEA_TOOLS_USER", "")
+	t.Setenv("MESH_GITEA_ADMIN_USER", "")
+	t.Setenv("MESH_GITEA_ADMIN_PASSWORD_FILE", "")
+	f, err := ForgeFromEnv()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if f.TokenFile != "/state/token" || f.Account != "mesh-tools" || f.User != "" || f.PasswordFile != "" {
+		t.Fatalf("%+v", f.Client)
+	}
+}

modules/gitea/cmd/forge/commit.go

@@ -9,6 +9,8 @@ import (
 	"net/url"
 	"strings"
 	"unicode/utf8"
+
+	"gitea/internal/forgehttp"
 )
 
 // gitea_commit (novox/hq issue 375): one commit on a branch of its own, so an agent follows the branch / pull
@@ -211,7 +213,32 @@ func commit(ctx context.Context, f *Forge, a CommitAsk) (*Committed, error) {
 	// Read the rules, or refuse: a branch the rules could not be read for is never written (fails closed).
 	var rules []Protection
 	if err := f.GetJSON(ctx, repo+"/branch_protections", &rules); err != nil {
-		return nil, fmt.Errorf("the protection rules of %s/%s could not be read, so the commit was not judged and nothing was sent: %w", a.Owner, a.Repo, err)
+		var status *forgehttp.StatusError
+		if !errors.As(err, &status) || status.Status != http.StatusForbidden {
+			return nil, fmt.Errorf("the protection rules of %s/%s could not be read, so the commit was not judged and nothing was sent: %w", a.Owner, a.Repo, err)
+		}
+		// The rules are a repository administrator's to read, and the tools' account is none (novox/hq ADR 0365
+		// §2). What it may read is the protection the forge applies to an existing branch: one protected is
+		// refused here. A branch not made yet is covered by no rule this account can see, and the forge itself
+		// judges the commit that makes it against every rule, refusing one a rule guards.
+		if err := targetRefused(a.Branch, r.DefaultBranch, nil); err != nil {
+			return nil, err
+		}
+		b, err := f.branch(ctx, repo, a.Branch)
+		if err != nil {
+			return nil, fmt.Errorf("whether a protection rule guards %s of %s/%s could not be read, so nothing was sent: %w", a.Branch, a.Owner, a.Repo, err)
+		}
+		if b != nil && b.Protected {
+			rule := b.Rule
+			if rule == "" {
+				rule = a.Branch
+			}
+			rules = []Protection{{RuleName: rule}}
+			if !ruleCovers(rule, a.Branch) {
+				return nil, refuse("a commit on %s is refused: the protection rule %s guards it (novox/hq ADR 0266). Put it on a "+
+					"branch of its own. Nothing was sent", a.Branch, rule)
+			}
+		}
 	}
 	if err := targetRefused(a.Branch, r.DefaultBranch, rules); err != nil {
 		return nil, err

modules/gitea/cmd/forge/forge.go

@@ -11,8 +11,8 @@ import (
 	"gitea/internal/forgehttp"
 )
 
-// The forge as this bundle reaches it: its own HTTP interface on the machine, as the forge's admin account
-// (internal/forgehttp, shared with the npm-registry bundle beside it).
+// The forge as this bundle reaches it: its own HTTP interface on the machine, as the tools' own account (novox/hq
+// ADR 0365 §2; internal/forgehttp, shared with the npm-registry bundle beside it).
 
 // Forge is the forge's HTTP interface.
 type Forge struct {
@@ -91,12 +91,15 @@ func (p Protection) name() string {
 	return p.BranchName
 }
 
-// Branch is one branch with the commit it points at.
+// Branch is one branch with the commit it points at, and the protection the forge applies to it: what an account
+// that may not read the rules themselves (the tools' account, novox/hq ADR 0365) knows of them.
 type Branch struct {
 	Name   string `json:"name"`
 	Commit struct {
 		ID string `json:"id"`
 	} `json:"commit"`
+	Protected bool   `json:"protected"`
+	Rule      string `json:"effective_branch_protection_name"`
 }
 
 // branch is the named branch, nil when the forge has none of that name.

modules/gitea/cmd/forge/forge_test.go

@@ -619,11 +619,17 @@ func TestToolsAreTheOnesTheReadmeNamesAndTheManifestBuilds(t *testing.T) {
 			if len(a.Loads) != 1 || a.Loads[0] != a.Binary {
 				t.Errorf("the bundle loads %v, not its binary %s", a.Loads, a.Binary)
 			}
-			for _, k := range []string{"MESH_GITEA_URL", "MESH_GITEA_ADMIN_USER", "MESH_GITEA_ADMIN_PASSWORD_FILE"} {
+			// The tools' own account, never the admin login (novox/hq ADR 0365 §2).
+			for _, k := range []string{"MESH_GITEA_URL", "MESH_GITEA_TOOLS_USER", "MESH_GITEA_TOKEN_FILE"} {
 				if a.Env[k] == "" {
 					t.Errorf("the bundle is not given %s", k)
 				}
 			}
+			for _, k := range []string{"MESH_GITEA_ADMIN_USER", "MESH_GITEA_ADMIN_PASSWORD_FILE"} {
+				if a.Env[k] != "" {
+					t.Errorf("the bundle is given %s: it acts as the tools' account, not the administrator", k)
+				}
+			}
 		}
 	}
 	if !found {