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author | 2024-11-25 15:42:37 +0000 | |
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committer | 2024-11-25 15:42:37 +0000 | |
commit | 3fceb5fc1a83a6ba3ca3c314eef50f0b45cd6009 (patch) | |
tree | d9fd78a82ec2352aad47d50cd9176e150f600b07 /vendor/github.com/uptrace/bun/migrate/diff.go | |
parent | [bugfix] notification types missing from link header (#3571) (diff) | |
download | gotosocial-3fceb5fc1a83a6ba3ca3c314eef50f0b45cd6009.tar.xz |
bumps uptrace/bun dependencies to v1.2.6 (#3569)
Diffstat (limited to 'vendor/github.com/uptrace/bun/migrate/diff.go')
-rw-r--r-- | vendor/github.com/uptrace/bun/migrate/diff.go | 411 |
1 files changed, 411 insertions, 0 deletions
diff --git a/vendor/github.com/uptrace/bun/migrate/diff.go b/vendor/github.com/uptrace/bun/migrate/diff.go new file mode 100644 index 000000000..42e55dcde --- /dev/null +++ b/vendor/github.com/uptrace/bun/migrate/diff.go @@ -0,0 +1,411 @@ +package migrate + +import ( + "github.com/uptrace/bun/migrate/sqlschema" +) + +// changeset is a set of changes to the database schema definition. +type changeset struct { + operations []Operation +} + +// Add new operations to the changeset. +func (c *changeset) Add(op ...Operation) { + c.operations = append(c.operations, op...) +} + +// diff calculates the diff between the current database schema and the target state. +// The changeset is not sorted -- the caller should resolve dependencies before applying the changes. +func diff(got, want sqlschema.Database, opts ...diffOption) *changeset { + d := newDetector(got, want, opts...) + return d.detectChanges() +} + +func (d *detector) detectChanges() *changeset { + currentTables := d.current.GetTables() + targetTables := d.target.GetTables() + +RenameCreate: + for wantName, wantTable := range targetTables.FromOldest() { + + // A table with this name exists in the database. We assume that schema objects won't + // be renamed to an already existing name, nor do we support such cases. + // Simply check if the table definition has changed. + if haveTable, ok := currentTables.Get(wantName); ok { + d.detectColumnChanges(haveTable, wantTable, true) + d.detectConstraintChanges(haveTable, wantTable) + continue + } + + // Find all renamed tables. We assume that renamed tables have the same signature. + for haveName, haveTable := range currentTables.FromOldest() { + if _, exists := targetTables.Get(haveName); !exists && d.canRename(haveTable, wantTable) { + d.changes.Add(&RenameTableOp{ + TableName: haveTable.GetName(), + NewName: wantName, + }) + d.refMap.RenameTable(haveTable.GetName(), wantName) + + // Find renamed columns, if any, and check if constraints (PK, UNIQUE) have been updated. + // We need not check wantTable any further. + d.detectColumnChanges(haveTable, wantTable, false) + d.detectConstraintChanges(haveTable, wantTable) + currentTables.Delete(haveName) + continue RenameCreate + } + } + + // If wantTable does not exist in the database and was not renamed + // then we need to create this table in the database. + additional := wantTable.(*sqlschema.BunTable) + d.changes.Add(&CreateTableOp{ + TableName: wantTable.GetName(), + Model: additional.Model, + }) + } + + // Drop any remaining "current" tables which do not have a model. + for name, table := range currentTables.FromOldest() { + if _, keep := targetTables.Get(name); !keep { + d.changes.Add(&DropTableOp{ + TableName: table.GetName(), + }) + } + } + + targetFKs := d.target.GetForeignKeys() + currentFKs := d.refMap.Deref() + + for fk := range targetFKs { + if _, ok := currentFKs[fk]; !ok { + d.changes.Add(&AddForeignKeyOp{ + ForeignKey: fk, + ConstraintName: "", // leave empty to let each dialect apply their convention + }) + } + } + + for fk, name := range currentFKs { + if _, ok := targetFKs[fk]; !ok { + d.changes.Add(&DropForeignKeyOp{ + ConstraintName: name, + ForeignKey: fk, + }) + } + } + + return &d.changes +} + +// detechColumnChanges finds renamed columns and, if checkType == true, columns with changed type. +func (d *detector) detectColumnChanges(current, target sqlschema.Table, checkType bool) { + currentColumns := current.GetColumns() + targetColumns := target.GetColumns() + +ChangeRename: + for tName, tCol := range targetColumns.FromOldest() { + + // This column exists in the database, so it hasn't been renamed, dropped, or added. + // Still, we should not delete(columns, thisColumn), because later we will need to + // check that we do not try to rename a column to an already a name that already exists. + if cCol, ok := currentColumns.Get(tName); ok { + if checkType && !d.equalColumns(cCol, tCol) { + d.changes.Add(&ChangeColumnTypeOp{ + TableName: target.GetName(), + Column: tName, + From: cCol, + To: d.makeTargetColDef(cCol, tCol), + }) + } + continue + } + + // Column tName does not exist in the database -- it's been either renamed or added. + // Find renamed columns first. + for cName, cCol := range currentColumns.FromOldest() { + // Cannot rename if a column with this name already exists or the types differ. + if _, exists := targetColumns.Get(cName); exists || !d.equalColumns(tCol, cCol) { + continue + } + d.changes.Add(&RenameColumnOp{ + TableName: target.GetName(), + OldName: cName, + NewName: tName, + }) + d.refMap.RenameColumn(target.GetName(), cName, tName) + currentColumns.Delete(cName) // no need to check this column again + + // Update primary key definition to avoid superficially recreating the constraint. + current.GetPrimaryKey().Columns.Replace(cName, tName) + + continue ChangeRename + } + + d.changes.Add(&AddColumnOp{ + TableName: target.GetName(), + ColumnName: tName, + Column: tCol, + }) + } + + // Drop columns which do not exist in the target schema and were not renamed. + for cName, cCol := range currentColumns.FromOldest() { + if _, keep := targetColumns.Get(cName); !keep { + d.changes.Add(&DropColumnOp{ + TableName: target.GetName(), + ColumnName: cName, + Column: cCol, + }) + } + } +} + +func (d *detector) detectConstraintChanges(current, target sqlschema.Table) { +Add: + for _, want := range target.GetUniqueConstraints() { + for _, got := range current.GetUniqueConstraints() { + if got.Equals(want) { + continue Add + } + } + d.changes.Add(&AddUniqueConstraintOp{ + TableName: target.GetName(), + Unique: want, + }) + } + +Drop: + for _, got := range current.GetUniqueConstraints() { + for _, want := range target.GetUniqueConstraints() { + if got.Equals(want) { + continue Drop + } + } + + d.changes.Add(&DropUniqueConstraintOp{ + TableName: target.GetName(), + Unique: got, + }) + } + + targetPK := target.GetPrimaryKey() + currentPK := current.GetPrimaryKey() + + // Detect primary key changes + if targetPK == nil && currentPK == nil { + return + } + switch { + case targetPK == nil && currentPK != nil: + d.changes.Add(&DropPrimaryKeyOp{ + TableName: target.GetName(), + PrimaryKey: *currentPK, + }) + case currentPK == nil && targetPK != nil: + d.changes.Add(&AddPrimaryKeyOp{ + TableName: target.GetName(), + PrimaryKey: *targetPK, + }) + case targetPK.Columns != currentPK.Columns: + d.changes.Add(&ChangePrimaryKeyOp{ + TableName: target.GetName(), + Old: *currentPK, + New: *targetPK, + }) + } +} + +func newDetector(got, want sqlschema.Database, opts ...diffOption) *detector { + cfg := &detectorConfig{ + cmpType: func(c1, c2 sqlschema.Column) bool { + return c1.GetSQLType() == c2.GetSQLType() && c1.GetVarcharLen() == c2.GetVarcharLen() + }, + } + for _, opt := range opts { + opt(cfg) + } + + return &detector{ + current: got, + target: want, + refMap: newRefMap(got.GetForeignKeys()), + cmpType: cfg.cmpType, + } +} + +type diffOption func(*detectorConfig) + +func withCompareTypeFunc(f CompareTypeFunc) diffOption { + return func(cfg *detectorConfig) { + cfg.cmpType = f + } +} + +// detectorConfig controls how differences in the model states are resolved. +type detectorConfig struct { + cmpType CompareTypeFunc +} + +// detector may modify the passed database schemas, so it isn't safe to re-use them. +type detector struct { + // current state represents the existing database schema. + current sqlschema.Database + + // target state represents the database schema defined in bun models. + target sqlschema.Database + + changes changeset + refMap refMap + + // cmpType determines column type equivalence. + // Default is direct comparison with '==' operator, which is inaccurate + // due to the existence of dialect-specific type aliases. The caller + // should pass a concrete InspectorDialect.EquuivalentType for robust comparison. + cmpType CompareTypeFunc +} + +// canRename checks if t1 can be renamed to t2. +func (d detector) canRename(t1, t2 sqlschema.Table) bool { + return t1.GetSchema() == t2.GetSchema() && equalSignatures(t1, t2, d.equalColumns) +} + +func (d detector) equalColumns(col1, col2 sqlschema.Column) bool { + return d.cmpType(col1, col2) && + col1.GetDefaultValue() == col2.GetDefaultValue() && + col1.GetIsNullable() == col2.GetIsNullable() && + col1.GetIsAutoIncrement() == col2.GetIsAutoIncrement() && + col1.GetIsIdentity() == col2.GetIsIdentity() +} + +func (d detector) makeTargetColDef(current, target sqlschema.Column) sqlschema.Column { + // Avoid unneccessary type-change migrations if the types are equivalent. + if d.cmpType(current, target) { + target = &sqlschema.BaseColumn{ + Name: target.GetName(), + DefaultValue: target.GetDefaultValue(), + IsNullable: target.GetIsNullable(), + IsAutoIncrement: target.GetIsAutoIncrement(), + IsIdentity: target.GetIsIdentity(), + + SQLType: current.GetSQLType(), + VarcharLen: current.GetVarcharLen(), + } + } + return target +} + +type CompareTypeFunc func(sqlschema.Column, sqlschema.Column) bool + +// equalSignatures determines if two tables have the same "signature". +func equalSignatures(t1, t2 sqlschema.Table, eq CompareTypeFunc) bool { + sig1 := newSignature(t1, eq) + sig2 := newSignature(t2, eq) + return sig1.Equals(sig2) +} + +// signature is a set of column definitions, which allows "relation/name-agnostic" comparison between them; +// meaning that two columns are considered equal if their types are the same. +type signature struct { + + // underlying stores the number of occurences for each unique column type. + // It helps to account for the fact that a table might have multiple columns that have the same type. + underlying map[sqlschema.BaseColumn]int + + eq CompareTypeFunc +} + +func newSignature(t sqlschema.Table, eq CompareTypeFunc) signature { + s := signature{ + underlying: make(map[sqlschema.BaseColumn]int), + eq: eq, + } + s.scan(t) + return s +} + +// scan iterates over table's field and counts occurrences of each unique column definition. +func (s *signature) scan(t sqlschema.Table) { + for _, icol := range t.GetColumns().FromOldest() { + scanCol := icol.(*sqlschema.BaseColumn) + // This is slightly more expensive than if the columns could be compared directly + // and we always did s.underlying[col]++, but we get type-equivalence in return. + col, count := s.getCount(*scanCol) + if count == 0 { + s.underlying[*scanCol] = 1 + } else { + s.underlying[col]++ + } + } +} + +// getCount uses CompareTypeFunc to find a column with the same (equivalent) SQL type +// and returns its count. Count 0 means there are no columns with of this type. +func (s *signature) getCount(keyCol sqlschema.BaseColumn) (key sqlschema.BaseColumn, count int) { + for col, cnt := range s.underlying { + if s.eq(&col, &keyCol) { + return col, cnt + } + } + return keyCol, 0 +} + +// Equals returns true if 2 signatures share an identical set of columns. +func (s *signature) Equals(other signature) bool { + if len(s.underlying) != len(other.underlying) { + return false + } + for col, count := range s.underlying { + if _, countOther := other.getCount(col); countOther != count { + return false + } + } + return true +} + +// refMap is a utility for tracking superficial changes in foreign keys, +// which do not require any modificiation in the database. +// Modern SQL dialects automatically updated foreign key constraints whenever +// a column or a table is renamed. Detector can use refMap to ignore any +// differences in foreign keys which were caused by renamed column/table. +type refMap map[*sqlschema.ForeignKey]string + +func newRefMap(fks map[sqlschema.ForeignKey]string) refMap { + rm := make(map[*sqlschema.ForeignKey]string) + for fk, name := range fks { + rm[&fk] = name + } + return rm +} + +// RenameT updates table name in all foreign key definions which depend on it. +func (rm refMap) RenameTable(tableName string, newName string) { + for fk := range rm { + switch tableName { + case fk.From.TableName: + fk.From.TableName = newName + case fk.To.TableName: + fk.To.TableName = newName + } + } +} + +// RenameColumn updates column name in all foreign key definions which depend on it. +func (rm refMap) RenameColumn(tableName string, column, newName string) { + for fk := range rm { + if tableName == fk.From.TableName { + fk.From.Column.Replace(column, newName) + } + if tableName == fk.To.TableName { + fk.To.Column.Replace(column, newName) + } + } +} + +// Deref returns copies of ForeignKey values to a map. +func (rm refMap) Deref() map[sqlschema.ForeignKey]string { + out := make(map[sqlschema.ForeignKey]string) + for fk, name := range rm { + out[*fk] = name + } + return out +} |