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added data loss to sync_schema_result #1474

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Merged
fnc12 merged 1 commit into from
Feb 11, 2026
Merged

added data loss to sync_schema_result #1474

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40 changes: 40 additions & 0 deletions .vscode/tasks.json
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Original file line number Diff line number Diff line change
@@ -1,6 +1,46 @@
{
"version": "2.0.0",
"tasks": [
{
"label": "CMake Configure (C++17)",
"type": "shell",
"command": "cmake",
"args": [
"-B",
"${workspaceFolder}/build",
"-S",
"${workspaceFolder}",
"-DSQLITE_ORM_ENABLE_CXX_17=ON",
"-DBUILD_TESTING=ON",
"-DCMAKE_BUILD_TYPE=Debug"
],
"group": "build",
"problemMatcher": [],
"presentation": {
"reveal": "always",
"panel": "shared"
}
},
{
"label": "CMake Build (C++17)",
"type": "shell",
"command": "cmake",
"args": [
"--build",
"${workspaceFolder}/build",
"--parallel"
],
"group": {
"kind": "build",
"isDefault": true
},
"dependsOn": "CMake Configure (C++17)",
"problemMatcher": "$gcc",
"presentation": {
"reveal": "always",
"panel": "shared"
}
},
{
"label": "Run unit_tests",
"type": "shell",
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3 changes: 3 additions & 0 deletions dev/implementations/storage_definitions.h
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Original file line number Diff line number Diff line change
Expand Up @@ -110,6 +110,9 @@ namespace sqlite_orm::internal {
this->drop_create_with_loss(db, table);
}
res = schema_stat;
} else if (schema_stat == sync_schema_result::dropped_and_recreated_with_data_loss) {
this->drop_create_with_loss(db, table);
res = schema_stat;
}
}
}
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20 changes: 18 additions & 2 deletions dev/storage.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1132,6 +1132,7 @@ namespace sqlite_orm::internal {

auto dbTableInfo = this->pragma.table_xinfo(table.name);
auto res = sync_schema_result::already_in_sync;
bool canPreserveData = true;

// first let's see if table with such name exists..
auto gottaCreateTable = !this->table_exists(db, table.name);
Expand Down Expand Up @@ -1163,7 +1164,20 @@ namespace sqlite_orm::internal {
}
}
if (gottaCreateTable) {
res = sync_schema_result::dropped_and_recreated;
// check if any new columns prevent data preservation
for (const table_xinfo* colInfo: columnsToAdd) {
if (!table.find_column_generated_storage_type(colInfo->name)) {
if (colInfo->notnull && colInfo->dflt_value.empty()) {
canPreserveData = false;
if (attempt_to_preserve) {
*attempt_to_preserve = false;
};
break;
}
}
}
res = canPreserveData ? sync_schema_result::dropped_and_recreated
: sync_schema_result::dropped_and_recreated_with_data_loss;
} else {
if (!columnsToAdd.empty()) {
// extra storage columns than table columns
Expand All @@ -1179,6 +1193,7 @@ namespace sqlite_orm::internal {
} else {
if (colInfo->notnull && colInfo->dflt_value.empty()) {
gottaCreateTable = true;
canPreserveData = false;
// no matter if preserve is true or false, there is no way to preserve data, so we wont try!
if (attempt_to_preserve) {
*attempt_to_preserve = false;
Expand All @@ -1194,7 +1209,8 @@ namespace sqlite_orm::internal {
res = sync_schema_result::new_columns_added;
}
} else {
res = sync_schema_result::dropped_and_recreated;
res = canPreserveData ? sync_schema_result::dropped_and_recreated
: sync_schema_result::dropped_and_recreated_with_data_loss;
}
} else {
if (res != sync_schema_result::old_columns_removed) {
Expand Down
8 changes: 4 additions & 4 deletions dev/storage_base.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1123,11 +1123,11 @@ namespace sqlite_orm::internal {
(dbColumnInfo.hidden == 0) == (storageColumnInfo.hidden == 0);
if (!columnsAreEqual) {
notEqual = true;
break;
} else {
dbTableInfo.erase(dbColumnInfoIt);
storageTableInfo.erase(storageTableInfo.begin() + storageColumnInfoIndex);
--storageColumnInfoIndex;
}
dbTableInfo.erase(dbColumnInfoIt);
storageTableInfo.erase(storageTableInfo.begin() + storageColumnInfoIndex);
--storageColumnInfoIndex;
} else {
columnsToAdd.push_back(&storageColumnInfo);
}
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15 changes: 12 additions & 3 deletions dev/sync_schema_result.h
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Original file line number Diff line number Diff line change
Expand Up @@ -36,11 +36,18 @@ SQLITE_ORM_EXPORT namespace sqlite_orm {
/**
* old table is dropped and new is recreated. Reasons :
* 1. delete excess columns in the table than storage if preseve = false
* 2. Lacking columns in the table cannot be added due to NULL and DEFAULT constraint
* 3. Reasons 1 and 2 both together
* 4. data_type mismatch between table and storage.
* 2. Reasons 1 and 4 both together
* 3. data_type mismatch between table and storage.
* Data is preserved through a backup table when preserve = true.
*/
dropped_and_recreated,

/**
* old table is dropped and new is recreated with data loss.
* Data cannot be preserved because a new NOT NULL column without
* a default value is being added, making backup impossible.
*/
dropped_and_recreated_with_data_loss,
};

inline std::ostream& operator<<(std::ostream& os, sync_schema_result value) {
Expand All @@ -57,6 +64,8 @@ SQLITE_ORM_EXPORT namespace sqlite_orm {
return os << "old excess columns removed and new columns added";
case sync_schema_result::dropped_and_recreated:
return os << "old table dropped and recreated";
case sync_schema_result::dropped_and_recreated_with_data_loss:
return os << "old table dropped and recreated with data loss";
}
return os;
}
Expand Down
46 changes: 37 additions & 9 deletions include/sqlite_orm/sqlite_orm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -12390,11 +12390,18 @@ SQLITE_ORM_EXPORT namespace sqlite_orm {
/**
* old table is dropped and new is recreated. Reasons :
* 1. delete excess columns in the table than storage if preseve = false
* 2. Lacking columns in the table cannot be added due to NULL and DEFAULT constraint
* 3. Reasons 1 and 2 both together
* 4. data_type mismatch between table and storage.
* 2. Reasons 1 and 4 both together
* 3. data_type mismatch between table and storage.
* Data is preserved through a backup table when preserve = true.
*/
dropped_and_recreated,

/**
* old table is dropped and new is recreated with data loss.
* Data cannot be preserved because a new NOT NULL column without
* a default value is being added, making backup impossible.
*/
dropped_and_recreated_with_data_loss,
};

inline std::ostream& operator<<(std::ostream& os, sync_schema_result value) {
Expand All @@ -12411,6 +12418,8 @@ SQLITE_ORM_EXPORT namespace sqlite_orm {
return os << "old excess columns removed and new columns added";
case sync_schema_result::dropped_and_recreated:
return os << "old table dropped and recreated";
case sync_schema_result::dropped_and_recreated_with_data_loss:
return os << "old table dropped and recreated with data loss";
}
return os;
}
Expand Down Expand Up @@ -19784,11 +19793,11 @@ namespace sqlite_orm::internal {
(dbColumnInfo.hidden == 0) == (storageColumnInfo.hidden == 0);
if (!columnsAreEqual) {
notEqual = true;
break;
} else {
dbTableInfo.erase(dbColumnInfoIt);
storageTableInfo.erase(storageTableInfo.begin() + storageColumnInfoIndex);
--storageColumnInfoIndex;
}
dbTableInfo.erase(dbColumnInfoIt);
storageTableInfo.erase(storageTableInfo.begin() + storageColumnInfoIndex);
--storageColumnInfoIndex;
} else {
columnsToAdd.push_back(&storageColumnInfo);
}
Expand Down Expand Up @@ -25037,6 +25046,7 @@ namespace sqlite_orm::internal {

auto dbTableInfo = this->pragma.table_xinfo(table.name);
auto res = sync_schema_result::already_in_sync;
bool canPreserveData = true;

// first let's see if table with such name exists..
auto gottaCreateTable = !this->table_exists(db, table.name);
Expand Down Expand Up @@ -25068,7 +25078,20 @@ namespace sqlite_orm::internal {
}
}
if (gottaCreateTable) {
res = sync_schema_result::dropped_and_recreated;
// check if any new columns prevent data preservation
for (const table_xinfo* colInfo: columnsToAdd) {
if (!table.find_column_generated_storage_type(colInfo->name)) {
if (colInfo->notnull && colInfo->dflt_value.empty()) {
canPreserveData = false;
if (attempt_to_preserve) {
*attempt_to_preserve = false;
};
break;
}
}
}
res = canPreserveData ? sync_schema_result::dropped_and_recreated
: sync_schema_result::dropped_and_recreated_with_data_loss;
} else {
if (!columnsToAdd.empty()) {
// extra storage columns than table columns
Expand All @@ -25084,6 +25107,7 @@ namespace sqlite_orm::internal {
} else {
if (colInfo->notnull && colInfo->dflt_value.empty()) {
gottaCreateTable = true;
canPreserveData = false;
// no matter if preserve is true or false, there is no way to preserve data, so we wont try!
if (attempt_to_preserve) {
*attempt_to_preserve = false;
Expand All @@ -25099,7 +25123,8 @@ namespace sqlite_orm::internal {
res = sync_schema_result::new_columns_added;
}
} else {
res = sync_schema_result::dropped_and_recreated;
res = canPreserveData ? sync_schema_result::dropped_and_recreated
: sync_schema_result::dropped_and_recreated_with_data_loss;
}
} else {
if (res != sync_schema_result::old_columns_removed) {
Expand Down Expand Up @@ -26035,6 +26060,9 @@ namespace sqlite_orm::internal {
this->drop_create_with_loss(db, table);
}
res = schema_stat;
} else if (schema_stat == sync_schema_result::dropped_and_recreated_with_data_loss) {
this->drop_create_with_loss(db, table);
res = schema_stat;
}
}
}
Expand Down
75 changes: 74 additions & 1 deletion tests/sync_schema_tests.cpp
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Expand Up @@ -376,7 +376,7 @@ TEST_CASE("sync_schema") {
}
REQUIRE(syncSchemaSimulateRes == syncSchemaRes);
decltype(syncSchemaRes) expected{
{tableName, sync_schema_result::dropped_and_recreated},
{tableName, sync_schema_result::dropped_and_recreated_with_data_loss},
};
REQUIRE(syncSchemaRes == expected);
auto users = storage.get_all<User>();
Expand Down Expand Up @@ -469,6 +469,79 @@ TEST_CASE("sync_schema") {
}
}

// https://github.com/fnc12/sqlite_orm/issues/1462
TEST_CASE("Distinguish dropped_and_recreated with and without backup") {
struct MyTableRecord {
int id = 0;
std::string name;
};

auto storagePath = "issue1462.sqlite";
std::remove(storagePath);

SECTION("sequential schema changes (exact issue scenario)") {
// Step 1: create initial table with a single column, insert data
{
auto storage = make_storage(storagePath, make_table("MyTable", make_column("id", &MyTableRecord::id)));
storage.sync_schema(true);
storage.insert(MyTableRecord{1, ""});
storage.insert(MyTableRecord{2, ""});
}
// Step 2: add primary key — data should be preserved
{
auto storage =
make_storage(storagePath, make_table("MyTable", make_column("id", &MyTableRecord::id, primary_key())));
auto simulateRes = storage.sync_schema_simulate(true);
auto syncRes = storage.sync_schema(true);
REQUIRE(simulateRes == syncRes);
REQUIRE(syncRes.at("MyTable") == sync_schema_result::dropped_and_recreated);

auto allRecords = storage.get_all<MyTableRecord>();
REQUIRE(allRecords.size() == 2);
}
// Step 3: add NOT NULL column without default — data should be lost
{
auto storage = make_storage(storagePath,
make_table("MyTable",
make_column("id", &MyTableRecord::id, primary_key()),
make_column("name", &MyTableRecord::name)));
auto simulateRes = storage.sync_schema_simulate(true);
auto syncRes = storage.sync_schema(true);
REQUIRE(simulateRes == syncRes);
REQUIRE(syncRes.at("MyTable") == sync_schema_result::dropped_and_recreated_with_data_loss);

auto allRecords = storage.get_all<MyTableRecord>();
REQUIRE(allRecords.empty());
}
}

SECTION("combined pk change and new NOT NULL column in one step") {
// create initial table with a single column, insert data
{
auto storage = make_storage(storagePath, make_table("MyTable", make_column("id", &MyTableRecord::id)));
storage.sync_schema(true);
storage.insert(MyTableRecord{1, ""});
storage.insert(MyTableRecord{2, ""});
}
// add primary key AND NOT NULL column without default at once — data should be lost
{
auto storage = make_storage(storagePath,
make_table("MyTable",
make_column("id", &MyTableRecord::id, primary_key()),
make_column("name", &MyTableRecord::name)));
auto simulateRes = storage.sync_schema_simulate(true);
auto syncRes = storage.sync_schema(true);
REQUIRE(simulateRes == syncRes);
REQUIRE(syncRes.at("MyTable") == sync_schema_result::dropped_and_recreated_with_data_loss);

auto allRecords = storage.get_all<MyTableRecord>();
REQUIRE(allRecords.empty());
}
}

std::remove(storagePath);
}

TEST_CASE("sync_schema_simulate") {
struct Cols {
int Col1 = 0;
Expand Down
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