add debug logging around alloaction and

deallocation of connection handles

odbc-api/src/handles.rs

@@ -34,6 +34,7 @@ pub use {
     statement::{AsStatementRef, ParameterDescription, Statement, StatementImpl, StatementRef},
 };
 
+use log::debug;
 use odbc_sys::{Handle, HandleType, SQLFreeHandle, SqlReturn};
 use std::thread::panicking;
 
@@ -45,7 +46,9 @@ use std::thread::panicking;
 /// `handle` Must be a valid ODBC handle and `handle_type` must match its type.
 pub unsafe fn drop_handle(handle: Handle, handle_type: HandleType) {
     match SQLFreeHandle(handle_type, handle) {
-        SqlReturn::SUCCESS => (),
+        SqlReturn::SUCCESS => {
+            debug!("SQLFreeHandle dropped {handle:?} of type {handle_type:?}.");
+        },
         other => {
             // Avoid panicking, if we already have a panic. We don't want to mask the
             // original error.

odbc-api/src/handles/connection.rs

@@ -10,6 +10,7 @@ use super::{
     statement::StatementImpl,
     OutputStringBuffer, SqlResult,
 };
+use log::debug;
 use odbc_sys::{
     CompletionType, ConnectionAttribute, DriverConnectOption, HDbc, HEnv, HStmt, HWnd, Handle,
     HandleType, InfoType, Pointer, SQLAllocHandle, SQLDisconnect, SQLEndTran, IS_UINTEGER,
@@ -395,6 +396,13 @@ impl<'c> Connection<'c> {
             null_mut(),
         )
         .into_sql_result("SQLGetConnectAttr")
-        .on_success(|| out)
+        .on_success(|| {
+            let handle = self.handle;
+            debug!(
+                "SQLGetConnectAttr called with attribute '{attribute:?}' for connection \
+                '{handle:?}' reported '{out}'."
+            );
+            out
+        })
     }
 }

odbc-api/src/handles/environment.rs

@@ -5,6 +5,7 @@ use super::{
     sql_result::{ExtSqlReturn, SqlResult},
     Connection,
 };
+use log::debug;
 use odbc_sys::{
     AttrCpMatch, AttrOdbcVersion, EnvironmentAttribute, FetchOrientation, HDbc, HEnv, Handle,
     HandleType, SQLAllocHandle, SQLSetEnvAttr,
@@ -129,7 +130,10 @@ impl Environment {
         unsafe {
             SQLAllocHandle(HandleType::Dbc, self.as_handle(), &mut handle)
                 .into_sql_result("SQLAllocHandle")
-                .on_success(|| Connection::new(handle as HDbc))
+                .on_success(|| {
+                    let handle = handle as HDbc;
+                    debug!("SQLAllocHandle allocated connection (Dbc) handle '{handle:?}'");
+                    Connection::new(handle)})
         }
     }