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parser: optionally rewrite numbered params to positional params #306

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2 changes: 2 additions & 0 deletions internal/dinosql/config.go
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,8 @@ type PackageSettings struct {
EmitJSONTags bool `json:"emit_json_tags"`
EmitPreparedQueries bool `json:"emit_prepared_queries"`
Overrides []Override `json:"overrides"`
// HACK: this is only set in tests, only here till Kotlin support can be merged.
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@mightyguava mightyguava Jan 28, 2020

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I promise to remove this when Kolint support is merged :)

rewriteParams bool
}

type Override struct {
Expand Down
77 changes: 59 additions & 18 deletions internal/dinosql/parser.go
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Original file line number Diff line number Diff line change
Expand Up @@ -229,7 +229,8 @@ func ParseQueries(c core.Catalog, pkg PackageSettings) (*Result, error) {
continue
}
for _, stmt := range tree.Statements {
query, err := parseQuery(c, stmt, source)
rewriteParameters := pkg.rewriteParams
query, err := parseQuery(c, stmt, source, rewriteParameters)
if err == errUnsupportedStatementType {
continue
}
Expand Down Expand Up @@ -407,7 +408,7 @@ func validateCmd(n nodes.Node, name, cmd string) error {

var errUnsupportedStatementType = errors.New("parseQuery: unsupported statement type")

func parseQuery(c core.Catalog, stmt nodes.Node, source string) (*Query, error) {
func parseQuery(c core.Catalog, stmt nodes.Node, source string, rewriteParameters bool) (*Query, error) {
if err := validateParamRef(stmt); err != nil {
return nil, err
}
Expand Down Expand Up @@ -443,6 +444,16 @@ func parseQuery(c core.Catalog, stmt nodes.Node, source string) (*Query, error)
}
rvs := rangeVars(raw.Stmt)
refs := findParameters(raw.Stmt)
var edits []edit
if rewriteParameters {
edits, err = rewriteNumberedParameters(refs, raw, rawSQL)
if err != nil {
return nil, err
}
} else {
refs = uniqueParamRefs(refs)
sort.Slice(refs, func(i, j int) bool { return refs[i].ref.Number < refs[j].ref.Number })
}
params, err := resolveCatalogRefs(c, rvs, refs)
if err != nil {
return nil, err
Expand All @@ -452,7 +463,13 @@ func parseQuery(c core.Catalog, stmt nodes.Node, source string) (*Query, error)
if err != nil {
return nil, err
}
expanded, err := expand(c, raw, rawSQL)
expandEdits, err := expand(c, raw, rawSQL)
if err != nil {
return nil, err
}
edits = append(edits, expandEdits...)

expanded, err := editQuery(rawSQL, edits)
if err != nil {
return nil, err
}
Expand All @@ -472,6 +489,18 @@ func parseQuery(c core.Catalog, stmt nodes.Node, source string) (*Query, error)
}, nil
}

func rewriteNumberedParameters(refs []paramRef, raw nodes.RawStmt, sql string) ([]edit, error) {
edits := make([]edit, len(refs))
for i, ref := range refs {
edits[i] = edit{
Location: ref.ref.Location - raw.StmtLocation,
Old: fmt.Sprintf("$%d", ref.ref.Number),
New: "?",
}
}
return edits, nil
}

func stripComments(sql string) (string, []string, error) {
s := bufio.NewScanner(strings.NewReader(sql))
var lines, comments []string
Expand All @@ -494,7 +523,7 @@ type edit struct {
New string
}

func expand(c core.Catalog, raw nodes.RawStmt, sql string) (string, error) {
func expand(c core.Catalog, raw nodes.RawStmt, sql string) ([]edit, error) {
list := search(raw, func(node nodes.Node) bool {
switch node.(type) {
case nodes.DeleteStmt:
Expand All @@ -507,17 +536,17 @@ func expand(c core.Catalog, raw nodes.RawStmt, sql string) (string, error) {
return true
})
if len(list.Items) == 0 {
return sql, nil
return nil, nil
}
var edits []edit
for _, item := range list.Items {
edit, err := expandStmt(c, raw, item)
if err != nil {
return "", err
return nil, err
}
edits = append(edits, edit...)
}
return editQuery(sql, edits)
return edits, nil
}

func expandStmt(c core.Catalog, raw nodes.RawStmt, node nodes.Node) ([]edit, error) {
Expand Down Expand Up @@ -958,7 +987,8 @@ type paramRef struct {
type paramSearch struct {
parent nodes.Node
rangeVar *nodes.RangeVar
refs map[int]paramRef
refs *[]paramRef
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@mightyguava mightyguava Jan 28, 2020 •
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So I tried to make Visit take a pointer receiver: (p *paramSearch), rather than doing a pointer to a slice here. This broke the DeleteVenue query parsing somehow. The parent for the second parameter became a FunctionCall instead of an Expr. I'm a compilers noob so I decided to not dive down that rabbit hole.

seen map[int]struct{}

// XXX: Gross state hack for limit
limitCount nodes.Node
Expand Down Expand Up @@ -1005,7 +1035,8 @@ func (p paramSearch) Visit(node nodes.Node) Visitor {
continue
}
// TODO: Out-of-bounds panic
p.refs[ref.Number] = paramRef{parent: n.Cols.Items[i], ref: ref, rv: p.rangeVar}
*p.refs = append(*p.refs, paramRef{parent: n.Cols.Items[i], ref: ref, rv: p.rangeVar})
p.seen[ref.Location] = struct{}{}
}
for _, vl := range s.ValuesLists {
for i, v := range vl {
Expand All @@ -1014,7 +1045,8 @@ func (p paramSearch) Visit(node nodes.Node) Visitor {
continue
}
// TODO: Out-of-bounds panic
p.refs[ref.Number] = paramRef{parent: n.Cols.Items[i], ref: ref, rv: p.rangeVar}
*p.refs = append(*p.refs, paramRef{parent: n.Cols.Items[i], ref: ref, rv: p.rangeVar})
p.seen[ref.Location] = struct{}{}
}
}
}
Expand Down Expand Up @@ -1050,7 +1082,7 @@ func (p paramSearch) Visit(node nodes.Node) Visitor {
parent = limitOffset{}
}
}
if _, found := p.refs[n.Number]; found {
if _, found := p.seen[n.Location]; found {
break
}

Expand All @@ -1072,21 +1104,18 @@ func (p paramSearch) Visit(node nodes.Node) Visitor {
}

if set {
p.refs[n.Number] = paramRef{parent: parent, ref: n, rv: p.rangeVar}
*p.refs = append(*p.refs, paramRef{parent: parent, ref: n, rv: p.rangeVar})
p.seen[n.Location] = struct{}{}
}
return nil
}
return p
}

func findParameters(root nodes.Node) []paramRef {
v := paramSearch{refs: map[int]paramRef{}}
Walk(v, root)
refs := make([]paramRef, 0)
for _, r := range v.refs {
refs = append(refs, r)
}
sort.Slice(refs, func(i, j int) bool { return refs[i].ref.Number < refs[j].ref.Number })
v := paramSearch{seen: make(map[int]struct{}), refs: &refs}
Walk(v, root)
return refs
}

Expand Down Expand Up @@ -1348,3 +1377,15 @@ func resolveCatalogRefs(c core.Catalog, rvs []nodes.RangeVar, args []paramRef) (
}
return a, nil
}

func uniqueParamRefs(in []paramRef) []paramRef {
m := make(map[int]struct{}, len(in))
o := make([]paramRef, 0, len(in))
for _, v := range in {
if _, ok := m[v.ref.Number]; !ok {
m[v.ref.Number] = struct{}{}
o = append(o, v)
}
}
return o
}
56 changes: 48 additions & 8 deletions internal/dinosql/parser_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@ package dinosql
import (
"testing"

"github.com/google/go-cmp/cmp"
pg "github.com/lfittl/pg_query_go"
nodes "github.com/lfittl/pg_query_go/nodes"
)
Expand Down Expand Up @@ -87,13 +88,14 @@ func TestLineColumn(t *testing.T) {

func TestExtractArgs(t *testing.T) {
queries := []struct {
query string
count int
query string
bindNumbers []int
}{
{"SELECT * FROM venue WHERE slug = $1 AND city = $2", 2},
{"SELECT * FROM venue WHERE slug = $1", 1},
{"SELECT * FROM venue LIMIT $1", 1},
{"SELECT * FROM venue OFFSET $1", 1},
{"SELECT * FROM venue WHERE slug = $1 AND city = $2", []int{1, 2}},
{"SELECT * FROM venue WHERE slug = $1 AND region = $2 AND city = $3 AND country = $2", []int{1, 2, 3, 2}},
{"SELECT * FROM venue WHERE slug = $1", []int{1}},
{"SELECT * FROM venue LIMIT $1", []int{1}},
{"SELECT * FROM venue OFFSET $1", []int{1}},
}
for _, q := range queries {
tree, err := pg.Parse(q.query)
Expand All @@ -105,8 +107,46 @@ func TestExtractArgs(t *testing.T) {
if err != nil {
t.Error(err)
}
if len(refs) != q.count {
t.Errorf("expected %d refs, got %d", q.count, len(refs))
nums := make([]int, len(refs))
for i, n := range refs {
nums[i] = n.ref.Number
}
if diff := cmp.Diff(q.bindNumbers, nums); diff != "" {
t.Errorf("expected bindings %v, got %v", q.bindNumbers, nums)
}
}
}
}

func TestRewriteParameters(t *testing.T) {
queries := []struct {
orig string
new string
}{
{"SELECT * FROM venue WHERE slug = $1 AND city = $3 AND bar = $2", "SELECT * FROM venue WHERE slug = ? AND city = ? AND bar = ?"},
{"DELETE FROM venue WHERE slug = $1 AND slug = $1", "DELETE FROM venue WHERE slug = ? AND slug = ?"},
{"SELECT * FROM venue LIMIT $1", "SELECT * FROM venue LIMIT ?"},
}
for _, q := range queries {
tree, err := pg.Parse(q.orig)
if err != nil {
t.Fatal(err)
}
for _, stmt := range tree.Statements {
refs := findParameters(stmt)
if err != nil {
t.Error(err)
}
edits, err := rewriteNumberedParameters(refs, stmt.(nodes.RawStmt), q.orig)
if err != nil {
t.Error(err)
}
rewritten, err := editQuery(q.orig, edits)
if err != nil {
t.Error(err)
}
if rewritten != q.new {
t.Errorf("expected %q, got %q", q.new, rewritten)
}
}
}
Expand Down