api: Make nvim_set_option() update `:verbose set ...`

Make `:verbose set ...` show when an option was last modified by an
API client or Lua script/chunk. In the case of an API client, the
channel ID is displayed.

11 files changed, 104 insertions, 44 deletions

diff --git a/src/nvim/api/buffer.c b/src/nvim/api/buffer.c
index 6be981a18e..023f434f9d 100644
--- a/src/nvim/api/buffer.c
+++ b/src/nvim/api/buffer.c
@@ -581,7 +581,8 @@ Object nvim_buf_get_option(Buffer buffer, String name, Error *err)
 /// @param name       Option name
 /// @param value      Option value
 /// @param[out] err   Error details, if any
-void nvim_buf_set_option(Buffer buffer, String name, Object value, Error *err)
+void nvim_buf_set_option(uint64_t channel_id, Buffer buffer,
+                         String name, Object value, Error *err)
   FUNC_API_SINCE(1)
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
@@ -590,7 +591,7 @@ void nvim_buf_set_option(Buffer buffer, String name, Object value, Error *err)
     return;
   }
 
-  set_option_to(buf, SREQ_BUF, name, value, err);
+  set_option_to(channel_id, buf, SREQ_BUF, name, value, err);
 }
 
 /// Gets the buffer number
diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 12a4279dd7..72542ed3e4 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -326,7 +326,8 @@ Object get_option_from(void *from, int type, String name, Error *err)
 /// @param type One of `SREQ_GLOBAL`, `SREQ_WIN` or `SREQ_BUF`
 /// @param name The option name
 /// @param[out] err Details of an error that may have occurred
-void set_option_to(void *to, int type, String name, Object value, Error *err)
+void set_option_to(uint64_t channel_id, void *to, int type,
+                   String name, Object value, Error *err)
 {
   if (name.size == 0) {
     api_set_error(err, kErrorTypeValidation, "Empty option name");
@@ -363,7 +364,8 @@ void set_option_to(void *to, int type, String name, Object value, Error *err)
     }
   }
 
-  int opt_flags = (type == SREQ_GLOBAL) ? OPT_GLOBAL : OPT_LOCAL;
+  int numval = 0;
+  char *stringval = NULL;
 
   if (flags & SOPT_BOOL) {
     if (value.type != kObjectTypeBoolean) {
@@ -374,8 +376,7 @@ void set_option_to(void *to, int type, String name, Object value, Error *err)
       return;
     }
 
-    bool val = value.data.boolean;
-    set_option_value_for(name.data, val, NULL, opt_flags, type, to, err);
+    numval = value.data.boolean;
   } else if (flags & SOPT_NUM) {
     if (value.type != kObjectTypeInteger) {
       api_set_error(err,
@@ -393,8 +394,7 @@ void set_option_to(void *to, int type, String name, Object value, Error *err)
       return;
     }
 
-    int val = (int) value.data.integer;
-    set_option_value_for(name.data, val, NULL, opt_flags, type, to, err);
+    numval = (int)value.data.integer;
   } else {
     if (value.type != kObjectTypeString) {
       api_set_error(err,
@@ -404,9 +404,18 @@ void set_option_to(void *to, int type, String name, Object value, Error *err)
       return;
     }
 
-    set_option_value_for(name.data, 0, value.data.string.data,
-            opt_flags, type, to, err);
+    stringval = (char *)value.data.string.data;
   }
+
+  const scid_T save_current_SID = current_SID;
+  current_SID = channel_id == LUA_INTERNAL_CALL ? SID_LUA : SID_API_CLIENT;
+  current_channel_id = channel_id;
+
+  const int opt_flags = (type == SREQ_GLOBAL) ? OPT_GLOBAL : OPT_LOCAL;
+  set_option_value_for(name.data, numval, stringval,
+                       opt_flags, type, to, err);
+
+  current_SID = save_current_SID;
 }
 
 #define TYPVAL_ENCODE_ALLOW_SPECIALS false
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index af3d379870..46ec8fe10b 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -549,10 +549,10 @@ Object nvim_get_option(String name, Error *err)
 /// @param name     Option name
 /// @param value    New option value
 /// @param[out] err Error details, if any
-void nvim_set_option(String name, Object value, Error *err)
+void nvim_set_option(uint64_t channel_id, String name, Object value, Error *err)
   FUNC_API_SINCE(1)
 {
-  set_option_to(NULL, SREQ_GLOBAL, name, value, err);
+  set_option_to(channel_id, NULL, SREQ_GLOBAL, name, value, err);
 }
 
 /// Writes a message to the Vim output buffer. Does not append "\n", the
diff --git a/src/nvim/api/window.c b/src/nvim/api/window.c
index 9bc91ef8fb..abfa0dc20b 100644
--- a/src/nvim/api/window.c
+++ b/src/nvim/api/window.c
@@ -309,7 +309,8 @@ Object nvim_win_get_option(Window window, String name, Error *err)
 /// @param name     Option name
 /// @param value    Option value
 /// @param[out] err Error details, if any
-void nvim_win_set_option(Window window, String name, Object value, Error *err)
+void nvim_win_set_option(uint64_t channel_id, Window window,
+                         String name, Object value, Error *err)
   FUNC_API_SINCE(1)
 {
   win_T *win = find_window_by_handle(window, err);
@@ -318,7 +319,7 @@ void nvim_win_set_option(Window window, String name, Object value, Error *err)
     return;
   }
 
-  set_option_to(win, SREQ_WIN, name, value, err);
+  set_option_to(channel_id, win, SREQ_WIN, name, value, err);
 }
 
 /// Gets the window position in display cells. First position is zero.
diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index 8de4286216..c8c2cd732c 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -237,7 +237,7 @@ typedef struct {
   char_u *wo_winhl;
 # define w_p_winhl w_onebuf_opt.wo_winhl    // 'winhighlight'
 
-  int wo_scriptID[WV_COUNT];            /* SIDs for window-local options */
+  LastSet wo_scriptID[WV_COUNT];        /* SIDs for window-local options */
 # define w_p_scriptID w_onebuf_opt.wo_scriptID
 } winopt_T;
 
@@ -590,7 +590,7 @@ struct file_buffer {
    */
   bool b_p_initialized;                 /* set when options initialized */
 
-  int b_p_scriptID[BV_COUNT];           /* SIDs for buffer-local options */
+  LastSet b_p_scriptID[BV_COUNT];       /* SIDs for buffer-local options */
 
   int b_p_ai;                   ///< 'autoindent'
   int b_p_ai_nopaste;           ///< b_p_ai saved for paste mode
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index cc29496968..c48c22fd96 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -22061,12 +22061,25 @@ int store_session_globals(FILE *fd)
  */
 void last_set_msg(scid_T scriptID)
 {
-  if (scriptID != 0) {
-    char_u *p = home_replace_save(NULL, get_scriptname(scriptID));
+  LastSet last_set;
+  last_set.script_id = scriptID;
+  option_last_set_msg(last_set);
+}
+
+/// Displays where an option was last set.
+///
+/// Should only be invoked when 'verbose' is non-zero.
+void option_last_set_msg(LastSet last_set)
+{
+  if (last_set.script_id != 0) {
+    bool should_free;
+    char_u *p = get_scriptname(last_set, &should_free);
     verbose_enter();
     MSG_PUTS(_("\n\tLast set from "));
     MSG_PUTS(p);
-    xfree(p);
+    if (should_free) {
+      xfree(p);
+    }
     verbose_leave();
   }
 }
diff --git a/src/nvim/ex_cmds2.c b/src/nvim/ex_cmds2.c
index 821c050c50..96d2102156 100644
--- a/src/nvim/ex_cmds2.c
+++ b/src/nvim/ex_cmds2.c
@@ -3055,24 +3055,32 @@ void scriptnames_slash_adjust(void)
 # endif
 
 /// Get a pointer to a script name.  Used for ":verbose set".
-char_u *get_scriptname(scid_T id)
-{
-  if (id == SID_MODELINE) {
-    return (char_u *)_("modeline");
-  }
-  if (id == SID_CMDARG) {
-    return (char_u *)_("--cmd argument");
-  }
-  if (id == SID_CARG) {
-    return (char_u *)_("-c argument");
-  }
-  if (id == SID_ENV) {
-    return (char_u *)_("environment variable");
-  }
-  if (id == SID_ERROR) {
-    return (char_u *)_("error handler");
+char_u *get_scriptname(LastSet last_set, bool *should_free)
+{
+  *should_free = false;
+
+  switch (last_set.script_id) {
+    case SID_MODELINE:
+      return (char_u *)_("modeline");
+    case SID_CMDARG:
+      return (char_u *)_("--cmd argument");
+    case SID_CARG:
+      return (char_u *)_("-c argument");
+    case SID_ENV:
+      return (char_u *)_("environment variable");
+    case SID_ERROR:
+      return (char_u *)_("error handler");
+    case SID_LUA:
+      return (char_u *)_("Lua");
+    case SID_API_CLIENT:
+      vim_snprintf((char *)IObuff, IOSIZE,
+                   _("API client (channel id %" PRIu64 ")"),
+                   last_set.channel_id);
+      return IObuff;
+    default:
+      *should_free = true;
+      return home_replace_save(NULL, SCRIPT_ITEM(last_set.script_id).sn_name);
   }
-  return SCRIPT_ITEM(id).sn_name;
 }
 
 # if defined(EXITFREE)
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index e02100e933..1d49d6d26c 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -397,9 +397,13 @@ EXTERN int garbage_collect_at_exit INIT(= FALSE);
 #define SID_ENV         -4      /* for sourcing environment variable */
 #define SID_ERROR       -5      /* option was reset because of an error */
 #define SID_NONE        -6      /* don't set scriptID */
+#define SID_LUA         -7      /* for Lua scripts/chunks */
+#define SID_API_CLIENT  -8      /* for API clients */
 
 /* ID of script being sourced or was sourced to define the current function. */
 EXTERN scid_T current_SID INIT(= 0);
+/* ID of the current channel making a client API call */
+EXTERN uint64_t current_channel_id INIT(= 0);
 
 EXTERN bool did_source_packages INIT(= false);
 
diff --git a/src/nvim/option.c b/src/nvim/option.c
index 48fd797ee9..a2120b9ab4 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -196,7 +196,7 @@ typedef struct vimoption {
   idopt_T indir;                /* global option: PV_NONE;
                                  * local option: indirect option index */
   char_u      *def_val[2];      /* default values for variable (vi and vim) */
-  scid_T scriptID;              /* script in which the option was last set */
+  LastSet last_set;             /* script in which the option was last set */
 # define SCRIPTID_INIT , 0
 } vimoption_T;
 
@@ -1368,12 +1368,12 @@ do_set (
           if (p_verbose > 0) {
             /* Mention where the option was last set. */
             if (varp == options[opt_idx].var)
-              last_set_msg(options[opt_idx].scriptID);
+              option_last_set_msg(options[opt_idx].last_set);
             else if ((int)options[opt_idx].indir & PV_WIN)
-              last_set_msg(curwin->w_p_scriptID[
+              option_last_set_msg(curwin->w_p_scriptID[
                     (int)options[opt_idx].indir & PV_MASK]);
             else if ((int)options[opt_idx].indir & PV_BUF)
-              last_set_msg(curbuf->b_p_scriptID[
+              option_last_set_msg(curbuf->b_p_scriptID[
                     (int)options[opt_idx].indir & PV_MASK]);
           }
         } else {
@@ -3663,16 +3663,18 @@ static void set_option_scriptID_idx(int opt_idx, int opt_flags, int id)
 {
   int both = (opt_flags & (OPT_LOCAL | OPT_GLOBAL)) == 0;
   int indir = (int)options[opt_idx].indir;
+  const LastSet last_set = { id, current_channel_id };
 
   /* Remember where the option was set.  For local options need to do that
    * in the buffer or window structure. */
-  if (both || (opt_flags & OPT_GLOBAL) || (indir & (PV_BUF|PV_WIN)) == 0)
-    options[opt_idx].scriptID = id;
+  if (both || (opt_flags & OPT_GLOBAL) || (indir & (PV_BUF|PV_WIN)) == 0) {
+    options[opt_idx].last_set = last_set;
+  }
   if (both || (opt_flags & OPT_LOCAL)) {
     if (indir & PV_BUF)
-      curbuf->b_p_scriptID[indir & PV_MASK] = id;
+      curbuf->b_p_scriptID[indir & PV_MASK] = last_set;
     else if (indir & PV_WIN)
-      curwin->w_p_scriptID[indir & PV_MASK] = id;
+      curwin->w_p_scriptID[indir & PV_MASK] = last_set;
   }
 }
 
diff --git a/src/nvim/option_defs.h b/src/nvim/option_defs.h
index 66a49fd6e0..670af1cc76 100644
--- a/src/nvim/option_defs.h
+++ b/src/nvim/option_defs.h
@@ -3,6 +3,7 @@
 
 #include "nvim/types.h"
 #include "nvim/macros.h"  // For EXTERN
+#include "eval/typval.h"  // For scid_T
 
 // option_defs.h: definition of global variables for settable options
 
@@ -821,4 +822,10 @@ enum {
 
 #define SB_MAX 100000  // Maximum 'scrollback' value.
 
+/// Stores an identifier of a script or channel that last set an option.
+typedef struct {
+  scid_T script_id;        /// Script ID or one of SID_* special values.
+  uint64_t channel_id;     /// Only used when script_id is SID_API_CLIENT.
+} LastSet;
+
 #endif // NVIM_OPTION_DEFS_H
diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
index 718294d941..599280d684 100644
--- a/test/functional/api/vim_spec.lua
+++ b/test/functional/api/vim_spec.lua
@@ -291,6 +291,21 @@ describe('api', function()
       eq(false, status)
       ok(err:match('Invalid option name') ~= nil)
     end)
+
+    it('updates where the option was last set from', function()
+      nvim('set_option', 'equalalways', false)
+      local status, rv = pcall(nvim, 'command_output',
+        'verbose set equalalways?')
+      eq(true, status)
+      ok(nil ~= string.find(rv, 'noequalalways\n'..
+        '\tLast set from API client %(channel id %d+%)'))
+
+      nvim('execute_lua', 'vim.api.nvim_set_option("equalalways", true)', {})
+      local status, rv = pcall(nvim, 'command_output',
+        'verbose set equalalways?')
+      eq(true, status)
+      eq('  equalalways\n\tLast set from Lua', rv)
+    end)
   end)
 
   describe('nvim_{get,set}_current_buf, nvim_list_bufs', function()