feat(config): add ability to delete multivar

lib/src/bindings/config.dart

@@ -251,7 +251,7 @@ List<String> getMultivarValue(
 /// Set the value of a multivar config variable in the config file with the
 /// highest level (usually the local one).
 ///
-/// The regular expression is applied case-sensitively on the value.
+/// The regexp is applied case-sensitively on the value.
 void setMultivarValue(
   Pointer<git_config> cfg,
   String variable,
@@ -267,3 +267,20 @@ void setMultivarValue(
   calloc.free(regexpC);
   calloc.free(valueC);
 }
+
+/// Deletes one or several values from a multivar in the config file
+/// with the highest level (usually the local one).
+///
+/// The regexp is applied case-sensitively on the value.
+void deleteMultivar(
+  Pointer<git_config> cfg,
+  String variable,
+  String regexp,
+) {
+  final name = variable.toNativeUtf8().cast<Int8>();
+  final regexpC = regexp.toNativeUtf8().cast<Int8>();
+  libgit2.git_config_delete_multivar(cfg, name, regexpC);
+
+  calloc.free(name);
+  calloc.free(regexpC);
+}

lib/src/config.dart

@@ -105,12 +105,12 @@ class Config {
   /// Pointer to memory address for allocated config object.
   late Pointer<Pointer<git_config>> configPointer;
 
-  /// Returns map of all the config variables and their values
+  /// Returns map of all the config variables and their values.
   Map<String, String> getEntries() {
     return config.getEntries(configPointer.value);
   }
 
-  /// Returns the value of config [variable]
+  /// Returns the value of config [variable].
   String getValue(String variable) {
     try {
       return config.getValue(configPointer.value, variable);
@@ -119,7 +119,7 @@ class Config {
     }
   }
 
-  /// Sets the [value] of config [variable]
+  /// Sets the [value] of config [variable].
   void setValue(String variable, dynamic value) {
     try {
       if (value.runtimeType == bool) {
@@ -158,11 +158,20 @@ class Config {
   /// highest level (usually the local one).
   ///
   /// The [regexp] is applied case-sensitively on the value.
-  /// Empty [regexp] sets [value] for all values of a multivar [variable]
+  /// Empty [regexp] sets [value] for all values of a multivar [variable].
   void setMultivarValue(String variable, String regexp, String value) {
     config.setMultivarValue(configPointer.value, variable, regexp, value);
   }
 
+  /// Deletes one or several values from a multivar [variable] in the config file
+  /// with the highest level (usually the local one).
+  ///
+  /// The [regexp] is applied case-sensitively on the value.
+  /// Empty [regexp] deletes all values of a multivar [variable].
+  void deleteMultivar(String variable, String regexp) {
+    config.deleteMultivar(configPointer.value, variable, regexp);
+  }
+
   /// Releases memory allocated for config object.
   void close() {
     calloc.free(configPointer);

test/config_test.dart

@@ -80,6 +80,7 @@ void main() {
 
     group('deleteEntry()', () {
       test('successfully deletes entry', () {
+        expect(config.getValue('core.bare'), equals('false'));
         config.deleteEntry('core.bare');
         final entries = config.getEntries();
         expect(entries['core.bare'], isNull);
@@ -133,6 +134,37 @@ void main() {
         expect(multivarValues.length, equals(2));
       });
     });
+
+    group('deleteMultivar()', () {
+      test('successfully deletes value of a multivar', () {
+        expect(
+          config.getMultivarValue('core.gitproxy', regexp: 'for kernel.org\$'),
+          ['proxy-command for kernel.org'],
+        );
+
+        config.deleteMultivar('core.gitproxy', 'for kernel.org\$');
+
+        expect(
+          config.getMultivarValue('core.gitproxy', regexp: 'for kernel.org\$'),
+          [],
+        );
+      });
+
+      test('successfully deletes all values of a multivar when regexp is empty',
+          () {
+        expect(
+          config.getMultivarValue('core.gitproxy'),
+          [
+            'proxy-command for kernel.org',
+            'default-proxy',
+          ],
+        );
+
+        config.deleteMultivar('core.gitproxy', '');
+
+        expect(config.getMultivarValue('core.gitproxy'), []);
+      });
+    });
   });
   ;
 }