[chore] Update interactionPolicy sub-policy parsing in line with documented defaults (#4229)

# Description

> If this is a code change, please include a summary of what you've coded, and link to the issue(s) it closes/implements.
>
> If this is a documentation change, please briefly describe what you've changed and why.

Brings our parsing of unset sub-policies in line with the defaults documented here: https://docs.gotosocial.org/en/v0.19.1/federation/interaction_policy/#defaults-per-sub-policy

Closes https://codeberg.org/superseriousbusiness/gotosocial/issues/4146

Part of https://codeberg.org/superseriousbusiness/gotosocial/issues/4026

## Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: `[ ]` -> `[x]`

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [x] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [x] I/we have commented the added code, particularly in hard-to-understand areas.
- [ ] I/we have made any necessary changes to documentation.
- [x] I/we have added tests that cover new code.
- [x] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4229
Co-authored-by: tobi <tobi.smethurst@protonmail.com>
Co-committed-by: tobi <tobi.smethurst@protonmail.com>

internal/filter/interaction/interactable.go

@@ -84,8 +84,8 @@ func (f *Filter) StatusLikeable(
 	}
 
 	switch {
-	// If status has policy set, check against that.
-	case status.InteractionPolicy != nil:
+	// If status has canLike sub-policy set, check against that.
+	case status.InteractionPolicy != nil && status.InteractionPolicy.CanLike != nil:
 		return f.checkPolicy(
 			ctx,
 			requester,
@@ -95,19 +95,18 @@ func (f *Filter) StatusLikeable(
 
 	// If status is local and has no policy set,
 	// check against the default policy for this
-	// visibility, as we're interaction-policy aware.
+	// visibility, as we're canLike sub-policy aware.
 	case *status.Local:
-		policy := gtsmodel.DefaultInteractionPolicyFor(status.Visibility)
 		return f.checkPolicy(
 			ctx,
 			requester,
 			status,
-			policy.CanLike,
+			gtsmodel.DefaultCanLikeFor(status.Visibility),
 		)
 
 	// Otherwise, assume the status is from an
 	// instance that does not use / does not care
-	// about interaction policies, and just return OK.
+	// about canLike sub-policy, and just return OK.
 	default:
 		return &gtsmodel.PolicyCheckResult{
 			Permission: gtsmodel.PolicyPermissionAutomaticApproval,
@@ -235,8 +234,8 @@ func (f *Filter) StatusReplyable(
 	}
 
 	switch {
-	// If status has policy set, check against that.
-	case status.InteractionPolicy != nil:
+	// If status has canReply sub-policy set, check against that.
+	case status.InteractionPolicy != nil && status.InteractionPolicy.CanReply != nil:
 		return f.checkPolicy(
 			ctx,
 			requester,
@@ -245,20 +244,19 @@ func (f *Filter) StatusReplyable(
 		)
 
 	// If status is local and has no policy set,
-	// check against the default policy for this
-	// visibility, as we're interaction-policy aware.
+	// check against the default canReply for this
+	// visibility, as we're canReply sub-policy aware.
 	case *status.Local:
-		policy := gtsmodel.DefaultInteractionPolicyFor(status.Visibility)
 		return f.checkPolicy(
 			ctx,
 			requester,
 			status,
-			policy.CanReply,
+			gtsmodel.DefaultCanReplyFor(status.Visibility),
 		)
 
 	// Otherwise, assume the status is from an
 	// instance that does not use / does not care
-	// about interaction policies, and just return OK.
+	// about canReply sub-policy, and just return OK.
 	default:
 		return &gtsmodel.PolicyCheckResult{
 			Permission: gtsmodel.PolicyPermissionAutomaticApproval,
@@ -297,8 +295,8 @@ func (f *Filter) StatusBoostable(
 	}
 
 	switch {
-	// If status has policy set, check against that.
-	case status.InteractionPolicy != nil:
+	// If status has canAnnounce sub-policy set, check against that.
+	case status.InteractionPolicy != nil && status.InteractionPolicy.CanAnnounce != nil:
 		return f.checkPolicy(
 			ctx,
 			requester,
@@ -319,7 +317,7 @@ func (f *Filter) StatusBoostable(
 		)
 
 	// Status is from an instance that does not use
-	// or does not care about interaction policies.
+	// or does not care about canAnnounce sub-policy.
 	// We can boost it if it's unlisted or public.
 	case status.Visibility == gtsmodel.VisibilityPublic ||
 		status.Visibility == gtsmodel.VisibilityUnlocked:
@@ -340,7 +338,7 @@ func (f *Filter) checkPolicy(
 	ctx context.Context,
 	requester *gtsmodel.Account,
 	status *gtsmodel.Status,
-	rules gtsmodel.PolicyRules,
+	rules *gtsmodel.PolicyRules,
 ) (*gtsmodel.PolicyCheckResult, error) {
 
 	// Wrap context to be able to
@@ -349,8 +347,8 @@ func (f *Filter) checkPolicy(
 	fctx.Context = ctx
 
 	// Check if requester matches a PolicyValue
-	// to be always allowed to do this.
-	matchAlways, matchAlwaysValue, err := f.matchPolicy(fctx,
+	// to be automatically approved for this.
+	matchAutomatic, matchAutomaticValue, err := f.matchPolicy(fctx,
 		requester,
 		status,
 		rules.AutomaticApproval,
@@ -360,40 +358,40 @@ func (f *Filter) checkPolicy(
 	}
 
 	// Check if requester matches a PolicyValue
-	// to be allowed to do this pending approval.
-	matchWithApproval, _, err := f.matchPolicy(fctx,
+	// to be manually approved for this.
+	matchManual, _, err := f.matchPolicy(fctx,
 		requester,
 		status,
 		rules.ManualApproval,
 	)
 	if err != nil {
-		return nil, gtserror.Newf("error checking policy approval match: %w", err)
+		return nil, gtserror.Newf("error checking policy match: %w", err)
 	}
 
 	switch {
 
 	// Prefer explicit match,
-	// prioritizing "always".
-	case matchAlways == explicit:
+	// prioritizing automatic.
+	case matchAutomatic == explicit:
 		return &gtsmodel.PolicyCheckResult{
 			Permission:          gtsmodel.PolicyPermissionAutomaticApproval,
-			PermissionMatchedOn: &matchAlwaysValue,
+			PermissionMatchedOn: &matchAutomaticValue,
 		}, nil
 
-	case matchWithApproval == explicit:
+	case matchManual == explicit:
 		return &gtsmodel.PolicyCheckResult{
 			Permission: gtsmodel.PolicyPermissionManualApproval,
 		}, nil
 
 	// Then try implicit match,
-	// prioritizing "always".
-	case matchAlways == implicit:
+	// prioritizing automatic.
+	case matchAutomatic == implicit:
 		return &gtsmodel.PolicyCheckResult{
 			Permission:          gtsmodel.PolicyPermissionAutomaticApproval,
-			PermissionMatchedOn: &matchAlwaysValue,
+			PermissionMatchedOn: &matchAutomaticValue,
 		}, nil
 
-	case matchWithApproval == implicit:
+	case matchManual == implicit:
 		return &gtsmodel.PolicyCheckResult{
 			Permission: gtsmodel.PolicyPermissionManualApproval,
 		}, nil

internal/filter/interaction/interactable_test.go

@@ -0,0 +1,207 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package interaction_test
+
+import (
+	"strconv"
+	"testing"
+
+	"code.superseriousbusiness.org/gotosocial/internal/gtsmodel"
+	"code.superseriousbusiness.org/gotosocial/testrig"
+	"github.com/stretchr/testify/suite"
+)
+
+const (
+	rMediaPath    = "../../../testrig/media"
+	rTemplatePath = "../../../web/template"
+)
+
+type InteractionTestSuite struct {
+	suite.Suite
+
+	testStatuses map[string]*gtsmodel.Status
+	testAccounts map[string]*gtsmodel.Account
+}
+
+func (suite *InteractionTestSuite) SetupSuite() {
+	testrig.InitTestConfig()
+	testrig.InitTestLog()
+
+	suite.testStatuses = testrig.NewTestStatuses()
+	suite.testAccounts = testrig.NewTestAccounts()
+}
+
+func (suite *InteractionTestSuite) TestInteractable() {
+	testStructs := testrig.SetupTestStructs(rMediaPath, rTemplatePath)
+	defer testrig.TearDownTestStructs(testStructs)
+
+	// Take zork's introduction post
+	// as the base post for these tests.
+	modelStatus := suite.testStatuses["local_account_1_status_1"]
+
+	ctx := suite.T().Context()
+	for i, test := range []struct {
+		policy    *gtsmodel.InteractionPolicy
+		account   *gtsmodel.Account
+		likeable  gtsmodel.PolicyPermission
+		replyable gtsmodel.PolicyPermission
+		boostable gtsmodel.PolicyPermission
+	}{
+		{
+			// Nil policy. Should all be fine as
+			// it will fall back to the default then.
+			policy:    nil,
+			account:   suite.testAccounts["admin_account"],
+			likeable:  gtsmodel.PolicyPermissionAutomaticApproval,
+			replyable: gtsmodel.PolicyPermissionAutomaticApproval,
+			boostable: gtsmodel.PolicyPermissionAutomaticApproval,
+		},
+		{
+			// Nil canLike, everything else
+			// restricted to author only.
+			// Only the nil sub-policy should be OK.
+			policy: &gtsmodel.InteractionPolicy{
+				CanLike: nil,
+				CanReply: &gtsmodel.PolicyRules{
+					AutomaticApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValueAuthor,
+					},
+				},
+				CanAnnounce: &gtsmodel.PolicyRules{
+					AutomaticApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValueAuthor,
+					},
+				},
+			},
+			account:   suite.testAccounts["admin_account"],
+			likeable:  gtsmodel.PolicyPermissionAutomaticApproval,
+			replyable: gtsmodel.PolicyPermissionForbidden,
+			boostable: gtsmodel.PolicyPermissionForbidden,
+		},
+		{
+			// All restricted it's the author's own
+			// account checking, so all should be fine.
+			policy: &gtsmodel.InteractionPolicy{
+				CanLike: &gtsmodel.PolicyRules{
+					AutomaticApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValueAuthor,
+					},
+				},
+				CanReply: &gtsmodel.PolicyRules{
+					AutomaticApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValueAuthor,
+					},
+				},
+				CanAnnounce: &gtsmodel.PolicyRules{
+					AutomaticApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValueAuthor,
+					},
+				},
+			},
+			account:   suite.testAccounts["local_account_1"],
+			likeable:  gtsmodel.PolicyPermissionAutomaticApproval,
+			replyable: gtsmodel.PolicyPermissionAutomaticApproval,
+			boostable: gtsmodel.PolicyPermissionAutomaticApproval,
+		},
+		{
+			// Followers can like automatically,
+			// everything else requires manual approval.
+			policy: &gtsmodel.InteractionPolicy{
+				CanLike: &gtsmodel.PolicyRules{
+					AutomaticApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValueAuthor,
+						gtsmodel.PolicyValueFollowers,
+					},
+					ManualApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValuePublic,
+					},
+				},
+				CanReply: &gtsmodel.PolicyRules{
+					AutomaticApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValueAuthor,
+					},
+					ManualApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValuePublic,
+					},
+				},
+				CanAnnounce: &gtsmodel.PolicyRules{
+					AutomaticApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValueAuthor,
+					},
+					ManualApproval: gtsmodel.PolicyValues{
+						gtsmodel.PolicyValuePublic,
+					},
+				},
+			},
+			account:   suite.testAccounts["admin_account"],
+			likeable:  gtsmodel.PolicyPermissionAutomaticApproval,
+			replyable: gtsmodel.PolicyPermissionManualApproval,
+			boostable: gtsmodel.PolicyPermissionManualApproval,
+		},
+	} {
+		// Copy model status.
+		status := new(gtsmodel.Status)
+		*status = *modelStatus
+
+		// Set test policy on it.
+		status.InteractionPolicy = test.policy
+
+		// Check likeableRes.
+		likeableRes, err := testStructs.InteractionFilter.StatusLikeable(ctx, test.account, status)
+		if err != nil {
+			suite.FailNow(err.Error())
+		}
+		if likeableRes.Permission != test.likeable {
+			suite.Fail(
+				"failure in case "+strconv.FormatInt(int64(i), 10),
+				"expected likeable result \"%s\", got \"%s\"",
+				likeableRes.Permission, test.likeable,
+			)
+		}
+
+		// Check replable.
+		replyableRes, err := testStructs.InteractionFilter.StatusReplyable(ctx, test.account, status)
+		if err != nil {
+			suite.FailNow(err.Error())
+		}
+		if replyableRes.Permission != test.replyable {
+			suite.Fail(
+				"failure in case "+strconv.FormatInt(int64(i), 10),
+				"expected replyable result \"%s\", got \"%s\"",
+				replyableRes.Permission, test.replyable,
+			)
+		}
+
+		// Check boostable.
+		boostableRes, err := testStructs.InteractionFilter.StatusBoostable(ctx, test.account, status)
+		if err != nil {
+			suite.FailNow(err.Error())
+		}
+		if boostableRes.Permission != test.boostable {
+			suite.Fail(
+				"failure in case "+strconv.FormatInt(int64(i), 10),
+				"expected boostable result \"%s\", got \"%s\"",
+				boostableRes.Permission, test.boostable,
+			)
+		}
+	}
+}
+
+func TestInteractionTestSuite(t *testing.T) {
+	suite.Run(t, new(InteractionTestSuite))
+}