fix: parse dynamic table query from DDL

Previously we have been extracting the `query` portion of dynamic table
definitions from the stored DDL in Snowflake by searching for the string
position of keywords that preceded the query. However, this approach has
proven inadequate as there are many ways to write working dynamic table
definitions that conflict with string position assumptions.

Observing that definitions of views and materialized views have faced
similar challenges but are currently working, this commit extends the
existing ViewSelectStatementExtractor that is currently being used to
extract the query definition from view and materialized view DDL
statements, applying the same approach to dynamic table DDL statements.

pkg/resources/dynamic_table.go

@@ -3,12 +3,12 @@ package resources
 import (
 	"context"
 	"database/sql"
-	"errors"
 	"log"
 	"strings"
 
 	"github.com/Snowflake-Labs/terraform-provider-snowflake/pkg/helpers"
 	"github.com/Snowflake-Labs/terraform-provider-snowflake/pkg/sdk"
+	"github.com/Snowflake-Labs/terraform-provider-snowflake/pkg/snowflake"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 )
 
@@ -243,7 +243,8 @@ func ReadDynamicTable(d *schema.ResourceData, meta interface{}) error {
 		return err
 	}
 
-	query, err := getQueryFromDDL(dynamicTable.Text)
+	extractor := snowflake.NewViewSelectStatementExtractor(dynamicTable.Text)
+	query, err := extractor.ExtractDynamicTable()
 	if err != nil {
 		return err
 	}
@@ -254,33 +255,6 @@ func ReadDynamicTable(d *schema.ResourceData, meta interface{}) error {
 	return nil
 }
 
-/*
- * Previous implementation tried to match query part from the whole dynamic table DDL statement by just using `AS`.
- * It was failing for table names containing `AS` (like `REASON`). It was also failing for other parts containing `AS`.
- * We cannot simply match by ` AS ` because this can still be part of COMMENT or SELECT query itself.
- * We have considered not setting the query at all but it was not ideal because of:
- * - possible external changes to dynamic table (drop and recreate externally with different query);
- * - import not 100% correct.
- * We did not want to complicate the implementation too much by introducing parsers.
- * One more thing worth mentioning is the whitespace that can be introduced by the user that is still returned by SHOW.
- * For now, we just normalize the DDL before extraction of query.
- *
- * The outcome implementation matches by ` AS SELECT ` and checks the number of matches.
- * If more matches are found, the error is returned to inform user about possible cause of error.
- *
- * Refer to issue https://github.com/Snowflake-Labs/terraform-provider-snowflake/issues/2329.
- */
-func getQueryFromDDL(text string) (string, error) {
-	normalizedDDL := normalizeQuery(text)
-	matchSubstring := " AS SELECT "
-	matches := strings.Count(strings.ToUpper(normalizedDDL), matchSubstring)
-	if matches != 1 {
-		return "", errors.New("too many matches found. There is no way of getting ONLY the 'query' used to create the dynamic table from Snowflake. We try to get it from the whole creation statement but there may be cases where it fails. Please submit the issue on Github (refer to #2329)")
-	}
-	idx := strings.Index(strings.ToUpper(normalizedDDL), " AS SELECT ")
-	return strings.TrimSpace(normalizedDDL[idx+4:]), nil
-}
-
 func parseTargetLag(v interface{}) sdk.TargetLag {
 	var result sdk.TargetLag
 	tl := v.([]interface{})[0].(map[string]interface{})

pkg/resources/dynamic_table_acceptance_test.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"database/sql"
 	"fmt"
-	"regexp"
 	"strings"
 	"testing"
 
@@ -336,7 +335,7 @@ func TestAcc_DynamicTable_issue2329(t *testing.T) {
 func TestAcc_DynamicTable_issue2329_with_matching_comment(t *testing.T) {
 	dynamicTableName := strings.ToUpper(acctest.RandStringFromCharSet(4, acctest.CharSetAlpha) + "AS" + acctest.RandStringFromCharSet(4, acctest.CharSetAlpha))
 	tableName := dynamicTableName + "_table"
-	query := fmt.Sprintf(`select "id" from "%v"."%v"."%v"`, acc.TestDatabaseName, acc.TestSchemaName, tableName)
+	query := fmt.Sprintf(`with temp as (select "id" from "%v"."%v"."%v") select * from temp`, acc.TestDatabaseName, acc.TestSchemaName, tableName)
 	m := func() map[string]config.Variable {
 		return map[string]config.Variable{
 			"name":       config.StringVariable(dynamicTableName),
@@ -361,7 +360,10 @@ func TestAcc_DynamicTable_issue2329_with_matching_comment(t *testing.T) {
 			{
 				ConfigDirectory: acc.ConfigurationDirectory("TestAcc_DynamicTable_issue2329/1"),
 				ConfigVariables: m(),
-				ExpectError:     regexp.MustCompile(`too many matches found. There is no way of getting ONLY the 'query' used to create the dynamic table from Snowflake. We try to get it from the whole creation statement but there may be cases where it fails. Please submit the issue on Github \(refer to #2329\)`),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("snowflake_dynamic_table.dt", "name", dynamicTableName),
+					resource.TestCheckResourceAttr("snowflake_dynamic_table.dt", "query", query),
+				),
 			},
 		},
 	})

pkg/snowflake/parser.go

@@ -87,6 +87,36 @@ func (e *ViewSelectStatementExtractor) ExtractMaterializedView() (string, error)
 	return string(e.input[e.pos:]), nil
 }
 
+func (e *ViewSelectStatementExtractor) ExtractDynamicTable() (string, error) {
+	fmt.Printf("[DEBUG] extracting dynamic table query %s\n", string(e.input))
+	e.consumeSpace()
+	e.consumeToken("create")
+	e.consumeSpace()
+	e.consumeToken("or replace")
+	e.consumeSpace()
+	e.consumeToken("dynamic table")
+	e.consumeSpace()
+	e.consumeID()
+	// TODO column list
+	e.consumeSpace()
+	e.consumeComment()
+	e.consumeSpace()
+	e.consumeQuotedParameter("lag")
+	e.consumeSpace()
+	e.consumeTokenParameter("warehouse")
+	e.consumeSpace()
+	e.consumeTokenParameter("refresh_mode")
+	e.consumeSpace()
+	e.consumeTokenParameter("initialize")
+	e.consumeSpace()
+	e.consumeTokenParameter("warehouse")
+	e.consumeSpace()
+	e.consumeToken("as")
+	e.consumeSpace()
+
+	return string(e.input[e.pos:]), nil
+}
+
 // consumeToken will move e.pos forward iff the token is the next part of the input. Comparison is
 // case-insensitive. Will return true if consumed.
 func (e *ViewSelectStatementExtractor) consumeToken(t string) bool {
@@ -134,7 +164,11 @@ func (e *ViewSelectStatementExtractor) consumeNonSpace() {
 }
 
 func (e *ViewSelectStatementExtractor) consumeComment() {
-	if c := e.consumeToken("comment"); !c {
+	e.consumeQuotedParameter("comment")
+}
+
+func (e *ViewSelectStatementExtractor) consumeQuotedParameter(param string) {
+	if c := e.consumeToken(param); !c {
 		return
 	}
 
@@ -173,6 +207,21 @@ func (e *ViewSelectStatementExtractor) consumeComment() {
 	}
 }
 
+func (e *ViewSelectStatementExtractor) consumeTokenParameter(param string) {
+	if c := e.consumeToken(param); !c {
+		return
+	}
+
+	e.consumeSpace()
+
+	if c := e.consumeToken("="); !c {
+		return
+	}
+
+	e.consumeSpace()
+	e.consumeNonSpace()
+}
+
 func (e *ViewSelectStatementExtractor) consumeClusterBy() {
 	if e.input[e.pos] != '(' {
 		return

pkg/snowflake/parser_test.go

@@ -137,6 +137,69 @@ from bar;`
 	}
 }
 
+func TestViewSelectStatementExtractor_ExtractDynamicTable(t *testing.T) {
+	basic := "create dynamic table foo lag = 'DOWNSTREAM' refresh_mode = 'AUTO' initialize = 'ON_CREATE' warehouse = COMPUTE_WH as select * from bar;"
+	caps := "CREATE DYNAMIC TABLE FOO LAG = 'DOWNSTREAM' REFRESH_MODE = 'AUTO' INITIALIZE = 'ON_CREATE' WAREHOUSE = COMPUTE_WH AS SELECT * FROM BAR;"
+	parens := "create dynamic table foo lag = 'DOWNSTREAM' refresh_mode = 'AUTO' initialize = 'ON_CREATE' warehouse = COMPUTE_WH as (select * from bar);"
+	multiline := `
+create dynamic table foo
+lag = 'DOWNSTREAM'
+refresh_mode = 'AUTO'
+initialize = 'ON_CREATE'
+warehouse = COMPUTE_WH
+as select * from bar;`
+
+	multilineComment := `
+create dynamic table foo
+lag = 'DOWNSTREAM'
+refresh_mode = 'AUTO'
+initialize = 'ON_CREATE'
+warehouse = COMPUTE_WH
+as
+-- comment
+select *
+from bar;`
+
+	comment := `create dynamic table foo comment = 'asdf' lag = 'DOWNSTREAM' refresh_mode = 'AUTO' initialize = 'ON_CREATE' warehouse = COMPUTE_WH as select * from bar;`
+	commentEscape := `create dynamic table foo comment = 'asdf\'s are fun' lag = 'DOWNSTREAM' refresh_mode = 'AUTO' initialize = 'ON_CREATE' warehouse = COMPUTE_WH as select * from bar;`
+	orReplace := `create or replace dynamic table foo comment = 'asdf' lag = 'DOWNSTREAM' refresh_mode = 'AUTO' initialize = 'ON_CREATE' warehouse = COMPUTE_WH as select * from bar;`
+	identifier := `create or replace dynamic table "foo"."bar"."bam" comment = 'asdf\'s are fun' lag = 'DOWNSTREAM' refresh_mode = 'AUTO' initialize = 'ON_CREATE' warehouse = COMPUTE_WH as select * from bar;`
+
+	type args struct {
+		input string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    string
+		wantErr bool
+	}{
+		{"basic", args{basic}, "select * from bar;", false},
+		{"caps", args{caps}, "SELECT * FROM BAR;", false},
+		{"parens", args{parens}, "(select * from bar);", false},
+		{"multiline", args{multiline}, "select *\nfrom bar;", false},
+		{"multilineComment", args{multilineComment}, "-- comment\nselect *\nfrom bar;", false},
+		{"comment", args{comment}, "select * from bar;", false},
+		{"commentEscape", args{commentEscape}, "select * from bar;", false},
+		{"orReplace", args{orReplace}, "select * from bar;", false},
+		{"identifier", args{identifier}, "select * from bar;", false},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			e := NewViewSelectStatementExtractor(tt.args.input)
+			got, err := e.ExtractDynamicTable()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ViewSelectStatementExtractor.ExtractDynamicTable() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("ViewSelectStatementExtractor.ExtractDynamicTable() = '%v', want '%v'", got, tt.want)
+			}
+		})
+	}
+}
+
 func TestViewSelectStatementExtractor_consumeToken(t *testing.T) {
 	type fields struct {
 		input []rune