feat(dbml): @postgres/@sqlite dialect directives (#19)

Add parseable `@<namespace>[(<target>)]: <args>` directives embedded in DBML. They are stored losslessly on each object's Metadata, round-trip unchanged through the DBML writer, and are translated to SQL only by the writer for the matching dialect. - models: Directive type + catalog; Metadata map added to Column and Index - dbml reader: parse and attach directives at database/table/column/index level; line-numbered errors; repeatable by default with singleton duplicate detection. Fixes a preexisting bug where an `indexes {}` closing brace ended the table early, dropping trailing Note: and directive lines. - dbml writer: re-emit directives at their location; idempotent output - pgsql writer: PARTITION BY / INHERITS / WITH / TABLESPACE (table), STORAGE / COMPRESSION / identity (column), WITH / TABLESPACE (index) - sqlite writer: WITHOUT ROWID / STRICT (table), COLLATE (column) - --strict-directives flag on ReaderOptions and WriterOptions - docs/DBML_DIRECTIVES.md + reader/writer READMEs Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Ss2MY5J11cRGwEz86ZXk7d
2026-09-08 16:17:37 +02:00
parent f968e3d4a6
commit ce3b615b0a
27 changed files with 1674 additions and 91 deletions
@@ -0,0 +1,184 @@
+package pgsql
+
+import (
+	"fmt"
+	"strings"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+// directiveNamespace is the dialect namespace this writer consumes. Directives
+// for other namespaces (e.g. "sqlite") are ignored and never emitted as SQL.
+const directiveNamespace = "postgres"
+
+// pgHandledDirectives maps a directive location to the set of postgres keys this
+// writer knows how to translate. In strict mode an unknown key for this
+// namespace at a supported location is a hard error.
+var pgHandledDirectives = map[string]map[string]bool{
+	models.DirectiveLocationTable:  {"partition": true, "inherits": true, "with": true, "tablespace": true},
+	models.DirectiveLocationColumn: {"storage": true, "compression": true, "identity": true},
+	models.DirectiveLocationIndex:  {"with": true, "tablespace": true},
+}
+
+// checkDirectives validates postgres directives across a schema when strict mode
+// is enabled. It returns an error for any postgres directive whose key this
+// writer cannot translate. With strict mode off it is a no-op.
+func (w *Writer) checkDirectives(schema *models.Schema) error {
+	if w.options == nil || !w.options.StrictDirectives {
+		return nil
+	}
+	for _, table := range schema.Tables {
+		if err := checkObjectDirectives(table.Metadata, models.DirectiveLocationTable, table.Name); err != nil {
+			return err
+		}
+		for _, col := range table.Columns {
+			if err := checkObjectDirectives(col.Metadata, models.DirectiveLocationColumn, table.Name+"."+col.Name); err != nil {
+				return err
+			}
+		}
+		for _, idx := range table.Indexes {
+			if err := checkObjectDirectives(idx.Metadata, models.DirectiveLocationIndex, idx.Name); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func checkObjectDirectives(meta map[string]any, location, owner string) error {
+	for _, d := range models.DirectivesForNamespace(meta, directiveNamespace) {
+		if !pgHandledDirectives[location][d.Key] {
+			return fmt.Errorf("pgsql: %s: unsupported @postgres directive %q at %s level (strict mode)", owner, d.Key, location)
+		}
+	}
+	return nil
+}
+
+// upperLeadingClause upcases a known leading keyword phrase in a directive
+// argument so the emitted SQL reads conventionally. Identifiers that follow are
+// left untouched.
+func upperLeadingClause(args, lowerPrefix, upperPrefix string) string {
+	args = strings.TrimSpace(args)
+	if strings.HasPrefix(strings.ToLower(args), lowerPrefix) {
+		return upperPrefix + args[len(lowerPrefix):]
+	}
+	return args
+}
+
+// pgTableDirectiveSuffix returns the clause appended after the closing ")" of a
+// CREATE TABLE statement, e.g. " PARTITION BY RANGE (created_at) TABLESPACE fast".
+func pgTableDirectiveSuffix(table *models.Table) string {
+	directives := models.DirectivesForNamespace(table.Metadata, directiveNamespace)
+	if len(directives) == 0 {
+		return ""
+	}
+
+	byKey := firstByKey(directives)
+
+	var parts []string
+	if d, ok := byKey["partition"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "partition by", "PARTITION BY"))
+	}
+	if d, ok := byKey["inherits"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "inherits", "INHERITS"))
+	}
+	if d, ok := byKey["with"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "with", "WITH"))
+	}
+	if d, ok := byKey["tablespace"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "tablespace", "TABLESPACE"))
+	}
+	if len(parts) == 0 {
+		return ""
+	}
+	return " " + strings.Join(parts, " ")
+}
+
+// pgColumnDirectiveSuffix returns the clause appended to a column definition,
+// e.g. " STORAGE PLAIN" or " GENERATED ALWAYS AS IDENTITY".
+func pgColumnDirectiveSuffix(col *models.Column) string {
+	directives := models.DirectivesForNamespace(col.Metadata, directiveNamespace)
+	if len(directives) == 0 {
+		return ""
+	}
+	byKey := firstByKey(directives)
+
+	var parts []string
+	if d, ok := byKey["storage"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "storage", "STORAGE"))
+	}
+	if d, ok := byKey["compression"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "compression", "COMPRESSION"))
+	}
+	if d, ok := byKey["identity"]; ok {
+		parts = append(parts, identityClause(d.Args))
+	}
+	if len(parts) == 0 {
+		return ""
+	}
+	return " " + strings.Join(parts, " ")
+}
+
+// identityClause maps the two documented identity forms to standard SQL,
+// falling back to a verbatim (upcased-keyword) rendering.
+func identityClause(args string) string {
+	switch strings.ToLower(strings.Join(strings.Fields(args), " ")) {
+	case "identity always":
+		return "GENERATED ALWAYS AS IDENTITY"
+	case "identity default", "identity by default":
+		return "GENERATED BY DEFAULT AS IDENTITY"
+	default:
+		return upperLeadingClause(args, "identity", "IDENTITY")
+	}
+}
+
+// pgIndexDirectiveWith returns the parenthesised storage-parameter list from an
+// @postgres: with (...) index directive, e.g. "fillfactor=90", or "".
+func pgIndexDirectiveWith(index *models.Index) string {
+	for _, d := range models.DirectivesForNamespace(index.Metadata, directiveNamespace) {
+		if d.Key != "with" {
+			continue
+		}
+		inner := d.Args
+		if i := strings.Index(inner, "("); i >= 0 {
+			if j := strings.LastIndex(inner, ")"); j > i {
+				return strings.TrimSpace(inner[i+1 : j])
+			}
+		}
+		return strings.TrimSpace(strings.TrimPrefix(strings.ToLower(inner), "with"))
+	}
+	return ""
+}
+
+// pgIndexWithParams returns the storage-parameter list to use for an index,
+// preferring an @postgres: with (...) directive over the given fallback (e.g.
+// one derived from the index comment).
+func pgIndexWithParams(index *models.Index, fallback string) string {
+	if p := pgIndexDirectiveWith(index); p != "" {
+		return p
+	}
+	return fallback
+}
+
+// pgIndexDirectiveTablespace returns the tablespace name from an
+// @postgres: tablespace <name> index directive, or "".
+func pgIndexDirectiveTablespace(index *models.Index) string {
+	for _, d := range models.DirectivesForNamespace(index.Metadata, directiveNamespace) {
+		if d.Key == "tablespace" {
+			return strings.TrimSpace(strings.TrimPrefix(strings.ToLower(d.Args), "tablespace"))
+		}
+	}
+	return ""
+}
+
+// firstByKey indexes directives by key, keeping the first occurrence (the
+// documented postgres keys used here are all singletons).
+func firstByKey(directives []models.Directive) map[string]models.Directive {
+	byKey := make(map[string]models.Directive, len(directives))
+	for _, d := range directives {
+		if _, exists := byKey[d.Key]; !exists {
+			byKey[d.Key] = d
+		}
+	}
+	return byKey
+}