refactor(terminal): only remove const qualifier when necessary (#26386)

src/nvim/api/vim.c

@@ -1017,18 +1017,19 @@ Integer nvim_open_term(Buffer buffer, DictionaryOf(LuaRef) opts, Error *err)
     }
   }
 
-  TerminalOptions topts;
   Channel *chan = channel_alloc(kChannelStreamInternal);
   chan->stream.internal.cb = cb;
   chan->stream.internal.closed = false;
-  topts.data = chan;
-  // NB: overridden in terminal_check_size if a window is already
-  // displaying the buffer
-  topts.width = (uint16_t)MAX(curwin->w_width_inner - win_col_off(curwin), 0);
-  topts.height = (uint16_t)curwin->w_height_inner;
-  topts.write_cb = term_write;
-  topts.resize_cb = term_resize;
-  topts.close_cb = term_close;
+  TerminalOptions topts = {
+    .data = chan,
+    // NB: overridden in terminal_check_size if a window is already
+    // displaying the buffer
+    .width = (uint16_t)MAX(curwin->w_width_inner - win_col_off(curwin), 0),
+    .height = (uint16_t)curwin->w_height_inner,
+    .write_cb = term_write,
+    .resize_cb = term_resize,
+    .close_cb = term_close,
+  };
   channel_incref(chan);
   terminal_open(&chan->term, buf, topts);
   if (chan->term != NULL) {
@@ -1038,7 +1039,7 @@ Integer nvim_open_term(Buffer buffer, DictionaryOf(LuaRef) opts, Error *err)
   return (Integer)chan->id;
 }
 
-static void term_write(char *buf, size_t size, void *data)  // NOLINT(readability-non-const-parameter)
+static void term_write(const char *buf, size_t size, void *data)
 {
   Channel *chan = data;
   LuaRef cb = chan->stream.internal.cb;
@@ -1048,7 +1049,7 @@ static void term_write(char *buf, size_t size, void *data)  // NOLINT(readabilit
   MAXSIZE_TEMP_ARRAY(args, 3);
   ADD_C(args, INTEGER_OBJ((Integer)chan->id));
   ADD_C(args, BUFFER_OBJ(terminal_buf(chan->term)));
-  ADD_C(args, STRING_OBJ(((String){ .data = buf, .size = size })));
+  ADD_C(args, STRING_OBJ(((String){ .data = (char *)buf, .size = size })));
   textlock++;
   nlua_call_ref(cb, "input", args, false, NULL);
   textlock--;

src/nvim/channel.c

@@ -794,19 +794,20 @@ static void channel_callback_call(Channel *chan, CallbackReader *reader)
 /// and `buf` is assumed to be a new, unmodified buffer.
 void channel_terminal_open(buf_T *buf, Channel *chan)
 {
-  TerminalOptions topts;
-  topts.data = chan;
-  topts.width = chan->stream.pty.width;
-  topts.height = chan->stream.pty.height;
-  topts.write_cb = term_write;
-  topts.resize_cb = term_resize;
-  topts.close_cb = term_close;
+  TerminalOptions topts = {
+    .data = chan,
+    .width = chan->stream.pty.width,
+    .height = chan->stream.pty.height,
+    .write_cb = term_write,
+    .resize_cb = term_resize,
+    .close_cb = term_close,
+  };
   buf->b_p_channel = (OptInt)chan->id;  // 'channel' option
   channel_incref(chan);
   terminal_open(&chan->term, buf, topts);
 }
 
-static void term_write(char *buf, size_t size, void *data)
+static void term_write(const char *buf, size_t size, void *data)
 {
   Channel *chan = data;
   if (chan->stream.proc.in.closed) {

src/nvim/terminal.c

@@ -188,7 +188,7 @@ void terminal_teardown(void)
 
 static void term_output_callback(const char *s, size_t len, void *user_data)
 {
-  terminal_send((Terminal *)user_data, (char *)s, len);
+  terminal_send((Terminal *)user_data, s, len);
 }
 
 // public API {{{
@@ -680,7 +680,7 @@ void terminal_destroy(Terminal **termpp)
   }
 }
 
-void terminal_send(Terminal *term, char *data, size_t size)
+static void terminal_send(Terminal *term, const char *data, size_t size)
 {
   if (term->closed) {
     return;
@@ -762,7 +762,7 @@ void terminal_paste(int count, char **y_array, size_t y_size)
   vterm_keyboard_end_paste(curbuf->terminal->vt);
 }
 
-void terminal_send_key(Terminal *term, int c)
+static void terminal_send_key(Terminal *term, int c)
 {
   VTermModifier mod = VTERM_MOD_NONE;
 
@@ -780,7 +780,7 @@ void terminal_send_key(Terminal *term, int c)
   }
 }
 
-void terminal_receive(Terminal *term, char *data, size_t len)
+void terminal_receive(Terminal *term, const char *data, size_t len)
 {
   if (!data) {
     return;

src/nvim/terminal.h

@@ -4,7 +4,7 @@
 #include <stdint.h>
 
 typedef struct terminal Terminal;
-typedef void (*terminal_write_cb)(char *buffer, size_t size, void *data);
+typedef void (*terminal_write_cb)(const char *buffer, size_t size, void *data);
 typedef void (*terminal_resize_cb)(uint16_t width, uint16_t height, void *data);
 typedef void (*terminal_close_cb)(void *data);