fix: don't return error when SaveFileDialog is cancelled by the user

Author: FrancescoLuzzi

v2/internal/go-common-file-dialog/cfd/errors.go

@@ -4,4 +4,6 @@ import "errors"
 
 var (
 	ErrCancelled = errors.New("cancelled by user")
+	ErrInvalidGUID = errors.New("guid cannot be nil")
+	ErrEmptyFilters = errors.New("must specify at least one filter")
 )

v2/internal/go-common-file-dialog/cfd/iShellItemArray.go

@@ -58,7 +58,7 @@ func (vtbl *iShellItemArrayVtbl) getItemAt(objPtr unsafe.Pointer, index uintptr)
 		return "", err
 	}
 	if shellItem == nil {
-		return "", fmt.Errorf("shellItem is nil")
+		return "", ErrCancelled
 	}
 	defer shellItem.vtbl.release(unsafe.Pointer(shellItem))
 	return shellItem.vtbl.getDisplayName(unsafe.Pointer(shellItem))

v2/internal/go-common-file-dialog/cfd/vtblCommonFunc.go

@@ -34,7 +34,7 @@ func (vtbl *iModalWindowVtbl) show(objPtr unsafe.Pointer, hwnd uintptr) error {
 func (vtbl *iFileDialogVtbl) setFileTypes(objPtr unsafe.Pointer, filters []FileFilter) error {
 	cFileTypes := len(filters)
 	if cFileTypes < 0 {
-		return fmt.Errorf("must specify at least one filter")
+		return ErrEmptyFilters
 	}
 	comDlgFilterSpecs := make([]comDlgFilterSpec, cFileTypes)
 	for i := 0; i < cFileTypes; i++ {
@@ -168,7 +168,7 @@ func (vtbl *iFileDialogVtbl) getResultString(objPtr unsafe.Pointer) (string, err
 		return "", err
 	}
 	if shellItem == nil {
-		return "", fmt.Errorf("shellItem is nil")
+		return "", ErrCancelled
 	}
 	defer shellItem.vtbl.release(unsafe.Pointer(shellItem))
 	return shellItem.vtbl.getDisplayName(unsafe.Pointer(shellItem))
@@ -177,7 +177,7 @@ func (vtbl *iFileDialogVtbl) getResultString(objPtr unsafe.Pointer) (string, err
 func (vtbl *iFileDialogVtbl) setClientGuid(objPtr unsafe.Pointer, guid *ole.GUID) error {
 	// Ensure the GUID is not nil
 	if guid == nil {
-		return fmt.Errorf("guid cannot be nil")
+		return ErrInvalidGUID
 	}
 
 	// Call the SetClientGuid method

website/src/pages/changelog.mdx

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 - Fixed Window size issues on Wayland [PR](https://github.com/wailsapp/wails/pull/4047) by [@lyimmi](https://github.com/lyimmi)
+- Fixed SaveFileDialog cancellation result [PR](https://github.com/wailsapp/wails/pull/4253) by [@FrancescoLuzzi](https://github.com/FrancescoLuzzi)
 
 
 ### Changed
@@ -88,10 +89,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed CGO memory issue on Darwin by @leaanthony in [PR](https://github.com/wailsapp/wails/pull/3590)
 - Fixed an error that occurred when an author name contains a string that is not suitable for JSON. Fixed by @taiseiotsuka in [PR](https://github.com/wailsapp/wails/pull/3638)
 - Fixed MacOS build to use `outputfilename` from wails.json. [#3200](https://github.com/wailsapp/wails/issues/3200)
-- Fixed file drop events on windows. Fixed in [PR](https://github.com/wailsapp/wails/pull/3595) by @FrancescoLuzzi
 - Fixed doctor command not finding pkg-config on Solus. [PR #3670](https://github.com/wailsapp/wails/pull/3670) by [@ianmjones](https://github.com/ianmjones)
 - Fixed binding for struct fields that were exported but had no json tags. [PR #3678](https://github.com/wailsapp/wails/pull/3678)
-- Fixed file drop events on Windows in [PR](https://github.com/wailsapp/wails/pull/3595) by @FrancescoLuzzi
+- Fixed file drop events on Windows in [PR](https://github.com/wailsapp/wails/pull/3595) by [@FrancescoLuzzi](https://github.com/FrancescoLuzzi)
 - Modified `ZoomFactor` and `IsZoomControlEnabled` options to be Windows-only options in PR[#3644](https://github.com/wailsapp/wails/pull/3644) by @levinit
 - Added nil check for Drag-n-Drop on Windows. Fixed by in [PR](https://github.com/wailsapp/wails/pull/3597) by @leaanthony based on the suggestion by @Alpa-1 in [#3596](https://github.com/wailsapp/wails/issues/3596).
 - Fixed typos in various .mdx files. [PR #3628](https://github.com/wailsapp/wails/pull/3628) by [@deining](https://github.com/deining)