refactor: Make latest commits syntax sugar (sourcenetwork#890)

* Make latestCommits syntax sugar around commits

* Remove commit-type related code

query/graphql/mapper/commitSelect.go

@@ -12,25 +12,13 @@ package mapper
 
 import "github.com/sourcenetwork/defradb/client"
 
-// CommitType represents a type of [CommitSelect]
-type CommitType int
-
-const (
-	NoneCommitType = CommitType(iota)
-	LatestCommits
-	Commits
-)
-
 // CommitSelect represents a commit request from a consumer.
 //
 // E.g. commits, or latestCommits.
 type CommitSelect struct {
 	// The underlying Select, defining the information requested.
 	Select
 
-	// The type of commit select request.
-	Type CommitType
-
 	// The key of the target document for which to get commits for.
 	DocKey string
 
@@ -52,7 +40,6 @@ func (s *CommitSelect) cloneTo(index int) *CommitSelect {
 	return &CommitSelect{
 		Select:    *s.Select.cloneTo(index),
 		DocKey:    s.DocKey,
-		Type:      s.Type,
 		FieldName: s.FieldName,
 		Cid:       s.Cid,
 	}

query/graphql/mapper/mapper.go

@@ -791,7 +791,6 @@ func ToCommitSelect(ctx context.Context, txn datastore.Txn, parsed *parser.Commi
 	return &CommitSelect{
 		Select:    *underlyingSelect,
 		DocKey:    parsed.DocKey,
-		Type:      CommitType(parsed.Type),
 		FieldName: parsed.FieldName,
 		Depth:     parsed.Depth,
 		Cid:       parsed.Cid,

query/graphql/parser/commit.go

@@ -16,32 +16,18 @@ import (
 	"github.com/graphql-go/graphql/language/ast"
 
 	"github.com/sourcenetwork/defradb/client"
-	"github.com/sourcenetwork/defradb/errors"
+	"github.com/sourcenetwork/defradb/core"
 	parserTypes "github.com/sourcenetwork/defradb/query/graphql/parser/types"
 )
 
-type CommitType int
-
-const (
-	NoneCommitType = CommitType(iota)
-	LatestCommits
-	Commits
-)
-
 var (
-	commitNameToType = map[string]CommitType{
-		"latestCommits": LatestCommits,
-		"commits":       Commits,
-	}
-
 	_ Selection = (*CommitSelect)(nil)
 )
 
 type CommitSelect struct {
 	Alias string
 	Name  string
 
-	Type      CommitType
 	DocKey    string
 	FieldName client.Option[string]
 	Cid       string
@@ -75,12 +61,6 @@ func parseCommitSelect(field *ast.Field) (*CommitSelect, error) {
 		Alias: getFieldAlias(field),
 	}
 
-	var ok bool
-	commit.Type, ok = commitNameToType[commit.Name]
-	if !ok {
-		return nil, errors.New("Unknown Database query")
-	}
-
 	for _, argument := range field.Arguments {
 		prop := argument.Name.Value
 		if prop == parserTypes.DocKey {
@@ -142,6 +122,19 @@ func parseCommitSelect(field *ast.Field) (*CommitSelect, error) {
 		}
 	}
 
+	// latestCommits is just syntax sugar around a commits query
+	if commit.Name == parserTypes.LatestCommitsQueryName {
+		// Depth is not exposed as an input parameter for latestCommits,
+		// so we can blindly set it here without worrying about existing
+		// values
+		commit.Depth = client.Some(uint64(1))
+
+		if !commit.FieldName.HasValue() {
+			// latest commits defaults to composite commits only at the moment
+			commit.FieldName = client.Some(core.COMPOSITE_NAMESPACE)
+		}
+	}
+
 	// no sub fields (unlikely)
 	if field.SelectionSet == nil {
 		return commit, nil

query/graphql/parser/types/types.go

@@ -84,6 +84,8 @@ const (
 
 	ExplainLabel = "explain"
 
+	LatestCommitsQueryName = "latestCommits"
+
 	CommitTypeName  = "Commit"
 	LinksFieldName  = "links"
 	HeightFieldName = "height"

query/graphql/planner/commit.go

@@ -16,7 +16,6 @@ import (
 	cid "github.com/ipfs/go-cid"
 
 	"github.com/sourcenetwork/defradb/core"
-	"github.com/sourcenetwork/defradb/errors"
 	"github.com/sourcenetwork/defradb/query/graphql/mapper"
 )
 
@@ -107,20 +106,11 @@ func (n *commitSelectNode) Explain() (map[string]any, error) {
 }
 
 func (p *Planner) CommitSelect(parsed *mapper.CommitSelect) (planNode, error) {
-	// check type of commit select (all, latest, one)
-	var commit *commitSelectNode
-	var err error
-	switch parsed.Type {
-	case mapper.LatestCommits:
-		commit, err = p.commitSelectLatest(parsed)
-	case mapper.Commits:
-		commit, err = p.commitSelectAll(parsed)
-	default:
-		return nil, errors.New("Invalid CommitSelect type")
-	}
+	commit, err := p.buildCommitSelectNode(parsed)
 	if err != nil {
 		return nil, err
 	}
+
 	plan, err := p.SelectFromSource(&parsed.Select, commit, false, nil)
 	if err != nil {
 		return nil, err
@@ -132,34 +122,7 @@ func (p *Planner) CommitSelect(parsed *mapper.CommitSelect) (planNode, error) {
 	}, nil
 }
 
-// commitSelectLatest is a CommitSelect node initalized with a headsetScanNode and a DocKey
-func (p *Planner) commitSelectLatest(parsed *mapper.CommitSelect) (*commitSelectNode, error) {
-	headset := p.HeadScan(parsed)
-	dag := p.DAGScan(parsed, headset)
-	// @todo: Get Collection field ID
-	if !parsed.FieldName.HasValue() {
-		dag.field = core.COMPOSITE_NAMESPACE
-	} else {
-		dag.field = parsed.FieldName.Value()
-	}
-
-	if parsed.DocKey != "" {
-		key := core.DataStoreKey{}.WithDocKey(parsed.DocKey).WithFieldId(dag.field)
-		headset.key = key
-	}
-
-	commit := &commitSelectNode{
-		p:         p,
-		source:    dag,
-		docMapper: docMapper{&parsed.DocumentMapping},
-	}
-
-	return commit, nil
-}
-
-// commitSelectAll is a CommitSelect initialized with a headsetScanNode, and will
-// recursively return all graph commits in order.
-func (p *Planner) commitSelectAll(parsed *mapper.CommitSelect) (*commitSelectNode, error) {
+func (p *Planner) buildCommitSelectNode(parsed *mapper.CommitSelect) (*commitSelectNode, error) {
 	headset := p.HeadScan(parsed)
 	dag := p.DAGScan(parsed, headset)
 
@@ -191,11 +154,12 @@ func (p *Planner) commitSelectAll(parsed *mapper.CommitSelect) (*commitSelectNod
 	}
 
 	if parsed.Depth.HasValue() {
-		dag.depthLimit = uint32(parsed.Depth.Value())
+		dag.depthLimit = parsed.Depth.Value()
 	} else {
 		// infinite depth
-		dag.depthLimit = math.MaxUint32
+		dag.depthLimit = math.MaxUint64
 	}
+
 	// dag.key = &key
 	commit := &commitSelectNode{
 		p:         p,

query/graphql/planner/dagscan.go

@@ -146,8 +146,8 @@ type dagScanNode struct {
 	// since the depth check is done after the
 	// block scan.
 	// If we need an infinite depth, use math.MaxUint32
-	depthLimit   uint32
-	depthVisited uint32
+	depthLimit   uint64
+	depthVisited uint64
 	visitedNodes map[string]bool
 
 	queuedCids *list.List
@@ -312,7 +312,7 @@ func (n *dagScanNode) Next() (bool, error) {
 	n.depthVisited++
 	n.visitedNodes[n.currentCid.String()] = true // mark the current node as "visited"
 	if n.depthVisited < n.depthLimit {
-		// look for HEAD links
+		// traverse the merkle dag to fetch related commits
 		for _, h := range heads {
 			// queue our found heads
 			n.queuedCids.PushFront(h.Cid)

query/graphql/planner/select.go

@@ -294,10 +294,8 @@ func (n *selectNode) initFields(parsed *mapper.Select) ([]aggregateNode, error)
 					// a OneCommit subquery, with the supplied parameters.
 					commitSlct.DocKey = parsed.DocKeys.Value[0] // @todo check length
 					commitSlct.Cid = parsed.Cid
-					commitSlct.Type = mapper.Commits
-				} else {
-					commitSlct.Type = mapper.LatestCommits
 				}
+
 				commitPlan, err := n.p.CommitSelect(commitSlct)
 				if err != nil {
 					return nil, err