feat(lint): add linter rules for migration and naming conventions

* Implement migration safety rules: - MIG001: Warn on CREATE INDEX without CONCURRENT. - MIG002: Warn on ALTER TABLE ADD COLUMN NOT NULL without DEFAULT. - MIG003: Warn on ALTER TABLE ADD CONSTRAINT without NOT VALID. * Implement naming conventions rules: - NAM001: Warn on non-snake_case table names. - NAM002: Warn on non-snake_case column names in CREATE TABLE. - NAM003: Warn on non-snake_case function names. * Add test fixtures for all new rules.
2026-06-27 22:15:02 +02:00
parent 932c83dbad
commit 7fb76bae3d
16 changed files with 1032 additions and 12 deletions
@@ -0,0 +1,171 @@
+package lint
+
+import (
+	"fmt"
+
+	pg_query "github.com/pganalyze/pg_query_go/v6"
+
+	"github.com/hein/pgtidy/pkg/diagnostics"
+	"github.com/hein/pgtidy/pkg/pgast"
+)
+
+// MIG001 — CREATE INDEX without CONCURRENT.
+// A non-concurrent index build holds ShareLock for its entire duration,
+// blocking all writes on the table. In production migrations use
+// CREATE INDEX CONCURRENTLY instead.
+type ruleMIG001 struct{}
+
+func (ruleMIG001) ID() string                    { return "MIG001" }
+func (ruleMIG001) Severity() diagnostics.Severity { return diagnostics.SeverityWarning }
+
+func (ruleMIG001) Check(stmts []*pg_query.RawStmt, src string) []diagnostics.Diagnostic {
+	var out []diagnostics.Diagnostic
+	for _, raw := range stmts {
+		idx, ok := raw.Stmt.GetNode().(*pg_query.Node_IndexStmt)
+		if !ok {
+			continue
+		}
+		s := idx.IndexStmt
+		if s.Concurrent || s.Isconstraint {
+			continue
+		}
+		line, col := pgast.LocationToLineCol(src, pgast.FirstTokenOffset(src, int(raw.StmtLocation)))
+		out = append(out, diagnostics.Diagnostic{
+			RuleID:   "MIG001",
+			Severity: diagnostics.SeverityWarning,
+			Message:  fmt.Sprintf("CREATE INDEX on %q without CONCURRENT blocks writes; use CREATE INDEX CONCURRENTLY", relName(s.Relation)),
+			Line:     line,
+			Col:      col,
+		})
+	}
+	return out
+}
+
+// MIG002 — ALTER TABLE ADD COLUMN with NOT NULL and no DEFAULT.
+// Pre-PG11 this rewrites the whole table. Even on PG11+ the column may require
+// a costly table scan to validate the NOT NULL constraint when no DEFAULT is
+// supplied. Use a nullable column first, backfill, then add the constraint.
+type ruleMIG002 struct{}
+
+func (ruleMIG002) ID() string                    { return "MIG002" }
+func (ruleMIG002) Severity() diagnostics.Severity { return diagnostics.SeverityWarning }
+
+func (ruleMIG002) Check(stmts []*pg_query.RawStmt, src string) []diagnostics.Diagnostic {
+	var out []diagnostics.Diagnostic
+	for _, raw := range stmts {
+		alt, ok := raw.Stmt.GetNode().(*pg_query.Node_AlterTableStmt)
+		if !ok {
+			continue
+		}
+		tbl := alt.AlterTableStmt
+		for _, cmdNode := range tbl.Cmds {
+			cmd, ok := cmdNode.GetNode().(*pg_query.Node_AlterTableCmd)
+			if !ok {
+				continue
+			}
+			ac := cmd.AlterTableCmd
+			if ac.Subtype != pg_query.AlterTableType_AT_AddColumn {
+				continue
+			}
+			col, ok := ac.Def.GetNode().(*pg_query.Node_ColumnDef)
+			if !ok {
+				continue
+			}
+			if hasNotNullNoDefault(col.ColumnDef.Constraints) {
+				line, col2 := pgast.LocationToLineCol(src, pgast.FirstTokenOffset(src, int(raw.StmtLocation)))
+				out = append(out, diagnostics.Diagnostic{
+					RuleID:   "MIG002",
+					Severity: diagnostics.SeverityWarning,
+					Message:  fmt.Sprintf("ALTER TABLE %q ADD COLUMN with NOT NULL and no DEFAULT may rewrite the table; add nullable, backfill, then constrain", relName(tbl.Relation)),
+					Line:     line,
+					Col:      col2,
+				})
+			}
+		}
+	}
+	return out
+}
+
+// MIG003 — ALTER TABLE ADD CONSTRAINT (FK or CHECK) without NOT VALID.
+// Without NOT VALID, PostgreSQL validates all existing rows immediately,
+// holding locks that block concurrent writes. Use NOT VALID + a separate
+// VALIDATE CONSTRAINT to spread the lock window.
+type ruleMIG003 struct{}
+
+func (ruleMIG003) ID() string                    { return "MIG003" }
+func (ruleMIG003) Severity() diagnostics.Severity { return diagnostics.SeverityWarning }
+
+func (ruleMIG003) Check(stmts []*pg_query.RawStmt, src string) []diagnostics.Diagnostic {
+	var out []diagnostics.Diagnostic
+	for _, raw := range stmts {
+		alt, ok := raw.Stmt.GetNode().(*pg_query.Node_AlterTableStmt)
+		if !ok {
+			continue
+		}
+		tbl := alt.AlterTableStmt
+		for _, cmdNode := range tbl.Cmds {
+			cmd, ok := cmdNode.GetNode().(*pg_query.Node_AlterTableCmd)
+			if !ok {
+				continue
+			}
+			if cmd.AlterTableCmd.Subtype != pg_query.AlterTableType_AT_AddConstraint {
+				continue
+			}
+			con, ok := cmd.AlterTableCmd.Def.GetNode().(*pg_query.Node_Constraint)
+			if !ok {
+				continue
+			}
+			c := con.Constraint
+			if c.Contype != pg_query.ConstrType_CONSTR_FOREIGN && c.Contype != pg_query.ConstrType_CONSTR_CHECK {
+				continue
+			}
+			if c.SkipValidation {
+				continue // NOT VALID is present
+			}
+			kind := "FOREIGN KEY"
+			if c.Contype == pg_query.ConstrType_CONSTR_CHECK {
+				kind = "CHECK"
+			}
+			line, col := pgast.LocationToLineCol(src, pgast.FirstTokenOffset(src, int(raw.StmtLocation)))
+			out = append(out, diagnostics.Diagnostic{
+				RuleID:   "MIG003",
+				Severity: diagnostics.SeverityWarning,
+				Message:  fmt.Sprintf("ALTER TABLE %q ADD %s CONSTRAINT without NOT VALID validates all rows immediately; use NOT VALID + VALIDATE CONSTRAINT", relName(tbl.Relation), kind),
+				Line:     line,
+				Col:      col,
+			})
+		}
+	}
+	return out
+}
+
+// hasNotNullNoDefault returns true when the constraint list has CONSTR_NOTNULL
+// but no CONSTR_DEFAULT.
+func hasNotNullNoDefault(constraints []*pg_query.Node) bool {
+	hasNN := false
+	hasDef := false
+	for _, cn := range constraints {
+		c, ok := cn.GetNode().(*pg_query.Node_Constraint)
+		if !ok {
+			continue
+		}
+		switch c.Constraint.Contype {
+		case pg_query.ConstrType_CONSTR_NOTNULL:
+			hasNN = true
+		case pg_query.ConstrType_CONSTR_DEFAULT:
+			hasDef = true
+		}
+	}
+	return hasNN && !hasDef
+}
+
+// relName returns "schema.rel" or "rel" from a RangeVar.
+func relName(rv *pg_query.RangeVar) string {
+	if rv == nil {
+		return "?"
+	}
+	if rv.Schemaname != "" {
+		return rv.Schemaname + "." + rv.Relname
+	}
+	return rv.Relname
+}