Re-order drop DDL

Author: jayvdb

butane_core/src/migrations/adb.rs

@@ -616,7 +616,9 @@ pub fn diff(old: &ADB, new: &ADB) -> Vec<Operation> {
     }
 
     // Remove tables
-    let removed_tables = old_names.difference(&new_names);
+    let removed_tables: Vec<&String> = old_names.difference(&new_names).copied().collect();
+    let removed_tables =
+        reorder_table_drops(old, &removed_tables).expect("failed reordering table drops");
     for removed in removed_tables.clone() {
         let removed: &str = removed.as_ref();
         let table = old.tables.get(removed).expect("no table").clone();
@@ -644,6 +646,29 @@ pub fn diff(old: &ADB, new: &ADB) -> Vec<Operation> {
     ops
 }
 
+/// Drop tables without dependencies first.
+fn reorder_table_drops(old: &ADB, removed_table_names: &[&String]) -> Result<Vec<String>> {
+    use std::collections::HashSet;
+    let removed_table_names: HashSet<&String> = removed_table_names.iter().copied().collect();
+    let mut new_table_order: Vec<String> = vec![];
+    while new_table_order.len() != removed_table_names.len() {
+        for removed_table_name in &removed_table_names {
+            let removed_table = old
+                .tables
+                .get(*removed_table_name)
+                .ok_or(Error::MigrationError("Table should exist".to_string()))?;
+            for column in &removed_table.columns {
+                if let Some(_reference) = &column.reference {
+                    continue;
+                }
+            }
+            // No columns are a reference, so this table can be dropped first.
+            new_table_order.push((**removed_table_name).clone());
+        }
+    }
+    Ok(new_table_order)
+}
+
 fn col_by_name<'a>(columns: &'a [AColumn], name: &str) -> Option<&'a AColumn> {
     columns.iter().find(|c| c.name == name)
 }

examples/getting_started/.butane/migrations/20201229_144636751_init/pg_down.sql

@@ -1,4 +1,8 @@
+
+
+
+
+DROP TABLE Tag;
 DROP TABLE Blog;
-DROP TABLE Post;
 DROP TABLE Post_tags_Many;
-DROP TABLE Tag;
+DROP TABLE Post;

examples/getting_started/.butane/migrations/20201229_144636751_init/sqlite_down.sql

@@ -1,4 +1,8 @@
-DROP TABLE Blog;
-DROP TABLE Post;
+
+
+
+
 DROP TABLE Post_tags_Many;
+DROP TABLE Blog;
 DROP TABLE Tag;
+DROP TABLE Post;

examples/getting_started/src/butane_migrations.rs

@@ -160,8 +160,8 @@ pub fn get_migrations() -> Result<MemMigrations, butane::Error> {
         "sqlite": "CREATE TABLE Blog (\nid INTEGER NOT NULL PRIMARY KEY,\n\"name\" TEXT NOT NULL\n);\nCREATE TABLE Post (\nid INTEGER NOT NULL PRIMARY KEY,\ntitle TEXT NOT NULL,\nbody TEXT NOT NULL,\npublished INTEGER NOT NULL,\nblog INTEGER NOT NULL,\nbyline TEXT\n);\nCREATE TABLE Post_tags_Many (\nowner INTEGER NOT NULL,\nhas TEXT NOT NULL\n);\nCREATE TABLE Tag (\ntag TEXT NOT NULL PRIMARY KEY\n);\nCREATE TABLE IF NOT EXISTS butane_migrations (\n\"name\" TEXT NOT NULL PRIMARY KEY\n);\n"
       },
       "down": {
-        "pg": "DROP TABLE Blog;\nDROP TABLE Post;\nDROP TABLE Post_tags_Many;\nDROP TABLE Tag;\n",
-        "sqlite": "DROP TABLE Blog;\nDROP TABLE Post;\nDROP TABLE Post_tags_Many;\nDROP TABLE Tag;\n"
+        "pg": "\n\n\n\nDROP TABLE Tag;\nDROP TABLE Blog;\nDROP TABLE Post_tags_Many;\nDROP TABLE Post;\n",
+        "sqlite": "\n\n\n\nDROP TABLE Post_tags_Many;\nDROP TABLE Blog;\nDROP TABLE Tag;\nDROP TABLE Post;\n"
       }
     },
     "20201229_171630604_likes": {

examples/newtype/.butane/migrations/20240401_095709389_init/pg_down.sql

@@ -1,4 +1,9 @@
-DROP TABLE Blog;
+ALTER TABLE Post DROP CONSTRAINT Post_blog_fkey;
+ALTER TABLE Post_tags_Many DROP CONSTRAINT Post_tags_Many_owner_fkey;
+ALTER TABLE Post_tags_Many DROP CONSTRAINT Post_tags_Many_has_fkey;
+
+
 DROP TABLE Post;
 DROP TABLE Post_tags_Many;
+DROP TABLE Blog;
 DROP TABLE Tag;

examples/newtype/.butane/migrations/20240401_095709389_init/pg_up.sql

@@ -8,7 +8,7 @@ title TEXT NOT NULL,
 body TEXT NOT NULL,
 published BOOLEAN NOT NULL,
 blog BYTEA NOT NULL,
-byline TEXT ,
+byline TEXT,
 likes INTEGER NOT NULL
 );
 CREATE TABLE Post_tags_Many (

examples/newtype/.butane/migrations/20240401_095709389_init/sqlite_down.sql

@@ -1,4 +1,8 @@
+
+
+
+
+DROP TABLE Tag;
 DROP TABLE Blog;
 DROP TABLE Post;
 DROP TABLE Post_tags_Many;
-DROP TABLE Tag;

examples/newtype/.butane/migrations/20240406_035726416_tags/pg_up.sql

@@ -1,3 +1,6 @@
-DROP TABLE Post_tags_Many;
+
+ALTER TABLE Post_tags_Many DROP CONSTRAINT Post_tags_Many_owner_fkey;
+ALTER TABLE Post_tags_Many DROP CONSTRAINT Post_tags_Many_has_fkey;
 DROP TABLE Tag;
+DROP TABLE Post_tags_Many;
 ALTER TABLE Post ADD COLUMN tags JSONB NOT NULL DEFAULT null;

examples/newtype/.butane/migrations/20240406_035726416_tags/sqlite_up.sql

@@ -1,3 +1,5 @@
-DROP TABLE Post_tags_Many;
+
+
 DROP TABLE Tag;
+DROP TABLE Post_tags_Many;
 ALTER TABLE Post ADD COLUMN tags TEXT NOT NULL DEFAULT null;

examples/newtype/Cargo.toml

@@ -9,6 +9,7 @@ publish = false
 doc = false
 
 [features]
+debug = ["butane/log", "butane/debug"]
 default = ["pg", "sqlite", "sqlite-bundled"]
 pg = ["butane/pg"]
 sqlite = ["butane/sqlite"]

examples/newtype/src/butane_migrations.rs

@@ -209,12 +209,12 @@ pub fn get_migrations() -> Result<MemMigrations, butane::Error> {
       },
       "from": null,
       "up": {
-        "pg": "CREATE TABLE Blog (\nid BYTEA NOT NULL PRIMARY KEY,\n\"name\" TEXT NOT NULL\n);\nCREATE TABLE Post (\nid BYTEA NOT NULL PRIMARY KEY,\ntitle TEXT NOT NULL,\nbody TEXT NOT NULL,\npublished BOOLEAN NOT NULL,\nblog BYTEA NOT NULL,\nbyline TEXT ,\nlikes INTEGER NOT NULL\n);\nCREATE TABLE Post_tags_Many (\nowner BYTEA NOT NULL,\nhas TEXT NOT NULL\n);\nCREATE TABLE Tag (\ntag TEXT NOT NULL PRIMARY KEY\n);\nALTER TABLE Post ADD FOREIGN KEY (blog) REFERENCES Blog(id);\nALTER TABLE Post_tags_Many ADD FOREIGN KEY (owner) REFERENCES Post(id);\nALTER TABLE Post_tags_Many ADD FOREIGN KEY (has) REFERENCES Tag(tag);\nCREATE TABLE IF NOT EXISTS butane_migrations (\n\"name\" TEXT NOT NULL PRIMARY KEY\n);\n",
+        "pg": "CREATE TABLE Blog (\nid BYTEA NOT NULL PRIMARY KEY,\n\"name\" TEXT NOT NULL\n);\nCREATE TABLE Post (\nid BYTEA NOT NULL PRIMARY KEY,\ntitle TEXT NOT NULL,\nbody TEXT NOT NULL,\npublished BOOLEAN NOT NULL,\nblog BYTEA NOT NULL,\nbyline TEXT,\nlikes INTEGER NOT NULL\n);\nCREATE TABLE Post_tags_Many (\nowner BYTEA NOT NULL,\nhas TEXT NOT NULL\n);\nCREATE TABLE Tag (\ntag TEXT NOT NULL PRIMARY KEY\n);\nALTER TABLE Post ADD FOREIGN KEY (blog) REFERENCES Blog(id);\nALTER TABLE Post_tags_Many ADD FOREIGN KEY (owner) REFERENCES Post(id);\nALTER TABLE Post_tags_Many ADD FOREIGN KEY (has) REFERENCES Tag(tag);\nCREATE TABLE IF NOT EXISTS butane_migrations (\n\"name\" TEXT NOT NULL PRIMARY KEY\n);\n",
         "sqlite": "CREATE TABLE Blog (\nid BLOB NOT NULL PRIMARY KEY,\n\"name\" TEXT NOT NULL\n);\nCREATE TABLE Post (\nid BLOB NOT NULL PRIMARY KEY,\ntitle TEXT NOT NULL,\nbody TEXT NOT NULL,\npublished INTEGER NOT NULL,\nblog BLOB NOT NULL,\nbyline TEXT,\nlikes INTEGER NOT NULL,\nFOREIGN KEY (blog) REFERENCES Blog(id)\n);\nCREATE TABLE Post_tags_Many (\nowner BLOB NOT NULL,\nhas TEXT NOT NULL,\nFOREIGN KEY (owner) REFERENCES Post(id)\nFOREIGN KEY (has) REFERENCES Tag(tag)\n);\nCREATE TABLE Tag (\ntag TEXT NOT NULL PRIMARY KEY\n);\n\n\nCREATE TABLE IF NOT EXISTS butane_migrations (\n\"name\" TEXT NOT NULL PRIMARY KEY\n);\n"
       },
       "down": {
-        "pg": "DROP TABLE Blog;\nDROP TABLE Post;\nDROP TABLE Post_tags_Many;\nDROP TABLE Tag;\n",
-        "sqlite": "DROP TABLE Blog;\nDROP TABLE Post;\nDROP TABLE Post_tags_Many;\nDROP TABLE Tag;\n"
+        "pg": "ALTER TABLE Post DROP CONSTRAINT Post_blog_fkey;\nALTER TABLE Post_tags_Many DROP CONSTRAINT Post_tags_Many_owner_fkey;\nALTER TABLE Post_tags_Many DROP CONSTRAINT Post_tags_Many_has_fkey;\n\n\nDROP TABLE Post;\nDROP TABLE Post_tags_Many;\nDROP TABLE Blog;\nDROP TABLE Tag;\n",
+        "sqlite": "\n\n\n\nDROP TABLE Tag;\nDROP TABLE Blog;\nDROP TABLE Post;\nDROP TABLE Post_tags_Many;\n"
       }
     },
     "20240406_035726416_tags": {
@@ -372,8 +372,8 @@ pub fn get_migrations() -> Result<MemMigrations, butane::Error> {
       },
       "from": "20240401_095709389_init",
       "up": {
-        "pg": "DROP TABLE Post_tags_Many;\nDROP TABLE Tag;\nALTER TABLE Post ADD COLUMN tags JSONB NOT NULL DEFAULT null;\n",
-        "sqlite": "DROP TABLE Post_tags_Many;\nDROP TABLE Tag;\nALTER TABLE Post ADD COLUMN tags TEXT NOT NULL DEFAULT null;\n"
+        "pg": "\nALTER TABLE Post_tags_Many DROP CONSTRAINT Post_tags_Many_owner_fkey;\nALTER TABLE Post_tags_Many DROP CONSTRAINT Post_tags_Many_has_fkey;\nDROP TABLE Tag;\nDROP TABLE Post_tags_Many;\nALTER TABLE Post ADD COLUMN tags JSONB NOT NULL DEFAULT null;\n",
+        "sqlite": "\n\nDROP TABLE Tag;\nDROP TABLE Post_tags_Many;\nALTER TABLE Post ADD COLUMN tags TEXT NOT NULL DEFAULT null;\n"
       },
       "down": {
         "pg": "CREATE TABLE Post_tags_Many (\nowner BYTEA NOT NULL,\nhas TEXT NOT NULL\n);\nCREATE TABLE Tag (\ntag TEXT NOT NULL PRIMARY KEY\n);\nALTER TABLE Post DROP COLUMN tags;\nALTER TABLE Post_tags_Many ADD FOREIGN KEY (owner) REFERENCES Post(id);\nALTER TABLE Post_tags_Many ADD FOREIGN KEY (has) REFERENCES Tag(tag);\n",