Mark some symbols to be deprecated #minor (#698)

This change introduces the file deprecated.go, which contains any
constants, functions, and types that are slated to be deprecated in the
next major release.

These symbols are deprecated because they refer to old spellings in
pre-1.0 libgit2. This also makes the build be done with the
`-DDEPRECATE_HARD` flag to avoid regressions.

This, together with
[gorelease](https://godoc.org/golang.org/x/exp/cmd/gorelease)[1] should
make releases safer going forward.

1: More information about how that works at
   https://go.googlesource.com/exp/+/refs/heads/master/apidiff/README.md

1 files changed, 25 insertions, 24 deletions

diff --git a/checkout.go b/checkout.go
index c6b9c87..fa6609a 100644
--- a/checkout.go
+++ b/checkout.go
@@ -51,7 +51,7 @@ const (
 type CheckoutNotifyCallback func(why CheckoutNotifyType, path string, baseline, target, workdir DiffFile) ErrorCode
 type CheckoutProgressCallback func(path string, completed, total uint) ErrorCode
 
-type CheckoutOpts struct {
+type CheckoutOptions struct {
 	Strategy         CheckoutStrategy   // Default will be a dry run
 	DisableFilters   bool               // Don't apply filters like CRLF conversion
 	DirMode          os.FileMode        // Default is 0755
@@ -65,19 +65,20 @@ type CheckoutOpts struct {
 	Baseline         *Tree
 }
 
-func checkoutOptionsFromC(c *C.git_checkout_options) CheckoutOpts {
-	opts := CheckoutOpts{}
-	opts.Strategy = CheckoutStrategy(c.checkout_strategy)
-	opts.DisableFilters = c.disable_filters != 0
-	opts.DirMode = os.FileMode(c.dir_mode)
-	opts.FileMode = os.FileMode(c.file_mode)
-	opts.FileOpenFlags = int(c.file_open_flags)
-	opts.NotifyFlags = CheckoutNotifyType(c.notify_flags)
+func checkoutOptionsFromC(c *C.git_checkout_options) CheckoutOptions {
+	opts := CheckoutOptions{
+		Strategy:       CheckoutStrategy(c.checkout_strategy),
+		DisableFilters: c.disable_filters != 0,
+		DirMode:        os.FileMode(c.dir_mode),
+		FileMode:       os.FileMode(c.file_mode),
+		FileOpenFlags:  int(c.file_open_flags),
+		NotifyFlags:    CheckoutNotifyType(c.notify_flags),
+	}
 	if c.notify_payload != nil {
-		opts.NotifyCallback = pointerHandles.Get(c.notify_payload).(*CheckoutOpts).NotifyCallback
+		opts.NotifyCallback = pointerHandles.Get(c.notify_payload).(*CheckoutOptions).NotifyCallback
 	}
 	if c.progress_payload != nil {
-		opts.ProgressCallback = pointerHandles.Get(c.progress_payload).(*CheckoutOpts).ProgressCallback
+		opts.ProgressCallback = pointerHandles.Get(c.progress_payload).(*CheckoutOptions).ProgressCallback
 	}
 	if c.target_directory != nil {
 		opts.TargetDirectory = C.GoString(c.target_directory)
@@ -85,12 +86,12 @@ func checkoutOptionsFromC(c *C.git_checkout_options) CheckoutOpts {
 	return opts
 }
 
-func (opts *CheckoutOpts) toC() *C.git_checkout_options {
+func (opts *CheckoutOptions) toC() *C.git_checkout_options {
 	if opts == nil {
 		return nil
 	}
 	c := C.git_checkout_options{}
-	populateCheckoutOpts(&c, opts)
+	populateCheckoutOptions(&c, opts)
 	return &c
 }
 
@@ -110,7 +111,7 @@ func checkoutNotifyCallback(why C.git_checkout_notify_t, cpath *C.char, cbaselin
 	if cworkdir != nil {
 		workdir = diffFileFromC((*C.git_diff_file)(cworkdir))
 	}
-	opts := pointerHandles.Get(data).(*CheckoutOpts)
+	opts := pointerHandles.Get(data).(*CheckoutOptions)
 	if opts.NotifyCallback == nil {
 		return 0
 	}
@@ -119,17 +120,17 @@ func checkoutNotifyCallback(why C.git_checkout_notify_t, cpath *C.char, cbaselin
 
 //export checkoutProgressCallback
 func checkoutProgressCallback(path *C.char, completed_steps, total_steps C.size_t, data unsafe.Pointer) int {
-	opts := pointerHandles.Get(data).(*CheckoutOpts)
+	opts := pointerHandles.Get(data).(*CheckoutOptions)
 	if opts.ProgressCallback == nil {
 		return 0
 	}
 	return int(opts.ProgressCallback(C.GoString(path), uint(completed_steps), uint(total_steps)))
 }
 
-// Convert the CheckoutOpts struct to the corresponding
+// Convert the CheckoutOptions struct to the corresponding
 // C-struct. Returns a pointer to ptr, or nil if opts is nil, in order
 // to help with what to pass.
-func populateCheckoutOpts(ptr *C.git_checkout_options, opts *CheckoutOpts) *C.git_checkout_options {
+func populateCheckoutOptions(ptr *C.git_checkout_options, opts *CheckoutOptions) *C.git_checkout_options {
 	if opts == nil {
 		return nil
 	}
@@ -165,7 +166,7 @@ func populateCheckoutOpts(ptr *C.git_checkout_options, opts *CheckoutOpts) *C.gi
 	return ptr
 }
 
-func freeCheckoutOpts(ptr *C.git_checkout_options) {
+func freeCheckoutOptions(ptr *C.git_checkout_options) {
 	if ptr == nil {
 		return
 	}
@@ -180,12 +181,12 @@ func freeCheckoutOpts(ptr *C.git_checkout_options) {
 
 // Updates files in the index and the working tree to match the content of
 // the commit pointed at by HEAD. opts may be nil.
-func (v *Repository) CheckoutHead(opts *CheckoutOpts) error {
+func (v *Repository) CheckoutHead(opts *CheckoutOptions) error {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
 	cOpts := opts.toC()
-	defer freeCheckoutOpts(cOpts)
+	defer freeCheckoutOptions(cOpts)
 
 	ret := C.git_checkout_head(v.ptr, cOpts)
 	runtime.KeepAlive(v)
@@ -199,7 +200,7 @@ func (v *Repository) CheckoutHead(opts *CheckoutOpts) error {
 // Updates files in the working tree to match the content of the given
 // index. If index is nil, the repository's index will be used. opts
 // may be nil.
-func (v *Repository) CheckoutIndex(index *Index, opts *CheckoutOpts) error {
+func (v *Repository) CheckoutIndex(index *Index, opts *CheckoutOptions) error {
 	var iptr *C.git_index = nil
 	if index != nil {
 		iptr = index.ptr
@@ -209,7 +210,7 @@ func (v *Repository) CheckoutIndex(index *Index, opts *CheckoutOpts) error {
 	defer runtime.UnlockOSThread()
 
 	cOpts := opts.toC()
-	defer freeCheckoutOpts(cOpts)
+	defer freeCheckoutOptions(cOpts)
 
 	ret := C.git_checkout_index(v.ptr, iptr, cOpts)
 	runtime.KeepAlive(v)
@@ -220,12 +221,12 @@ func (v *Repository) CheckoutIndex(index *Index, opts *CheckoutOpts) error {
 	return nil
 }
 
-func (v *Repository) CheckoutTree(tree *Tree, opts *CheckoutOpts) error {
+func (v *Repository) CheckoutTree(tree *Tree, opts *CheckoutOptions) error {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
 	cOpts := opts.toC()
-	defer freeCheckoutOpts(cOpts)
+	defer freeCheckoutOptions(cOpts)
 
 	ret := C.git_checkout_tree(v.ptr, tree.ptr, cOpts)
 	runtime.KeepAlive(v)