Merge #4648 from jamessan/packages

packages (vim-patch:7.4.{1384,1388,1396,1478,1479,1480,1486,1492,1499,1528,1550,1551,1552,1553,1554,1596,1649,1712,1840,1973,1986})

18 files changed, 694 insertions, 330 deletions

diff --git a/src/nvim/digraph.c b/src/nvim/digraph.c
index 9525024c1b..aad145b3e5 100644
--- a/src/nvim/digraph.c
+++ b/src/nvim/digraph.c
@@ -1757,12 +1757,12 @@ char_u* keymap_init(void)
     vim_snprintf(buf, buflen, "keymap/%s_%s.vim",
                  curbuf->b_p_keymap, p_enc);
 
-    if (source_runtime((char_u *)buf, FALSE) == FAIL) {
+    if (source_runtime((char_u *)buf, 0) == FAIL) {
       // try finding "keymap/'keymap'.vim" in 'runtimepath'
       vim_snprintf(buf, buflen, "keymap/%s.vim",
                    curbuf->b_p_keymap);
 
-      if (source_runtime((char_u *)buf, FALSE) == FAIL) {
+      if (source_runtime((char_u *)buf, 0) == FAIL) {
         xfree(buf);
         return (char_u *)N_("E544: Keymap file not found");
       }
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 9a86c5765c..591ed50cfd 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -10782,6 +10782,7 @@ static void f_has(typval_T *argvars, typval_T *rettv)
     "mouse",
     "multi_byte",
     "multi_lang",
+    "packages",
     "path_extra",
     "persistent_undo",
     "postscript",
@@ -20497,9 +20498,10 @@ script_autoload (
       tofree = NULL;
     }
 
-    /* Try loading the package from $VIMRUNTIME/autoload/<name>.vim */
-    if (source_runtime(scriptname, FALSE) == OK)
-      ret = TRUE;
+    // Try loading the package from $VIMRUNTIME/autoload/<name>.vim
+    if (source_runtime(scriptname, 0) == OK) {
+      ret = true;
+    }
   }
 
   xfree(tofree);
diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index d0661b6b9b..da64533708 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -4796,122 +4796,15 @@ void ex_viusage(exarg_T *eap)
 }
 
 
-/*
- * ":helptags"
- */
-void ex_helptags(exarg_T *eap)
-{
-  garray_T ga;
-  int len;
-  char_u lang[2];
-  expand_T xpc;
-  char_u      *dirname;
-  char_u ext[5];
-  char_u fname[8];
-  int filecount;
-  char_u      **files;
-  int add_help_tags = FALSE;
-
-  /* Check for ":helptags ++t {dir}". */
-  if (STRNCMP(eap->arg, "++t", 3) == 0 && ascii_iswhite(eap->arg[3])) {
-    add_help_tags = TRUE;
-    eap->arg = skipwhite(eap->arg + 3);
-  }
-
-  ExpandInit(&xpc);
-  xpc.xp_context = EXPAND_DIRECTORIES;
-  dirname = ExpandOne(&xpc, eap->arg, NULL,
-      WILD_LIST_NOTFOUND|WILD_SILENT, WILD_EXPAND_FREE);
-  if (dirname == NULL || !os_isdir(dirname)) {
-    EMSG2(_("E150: Not a directory: %s"), eap->arg);
-    xfree(dirname);
-    return;
-  }
-
-  /* Get a list of all files in the help directory and in subdirectories. */
-  STRCPY(NameBuff, dirname);
-  add_pathsep((char *)NameBuff);
-  STRCAT(NameBuff, "**");
-
-  // Note: We cannot just do `&NameBuff` because it is a statically sized array
-  //       so `NameBuff == &NameBuff` according to C semantics.
-  char_u *buff_list[1] = {NameBuff};
-  if (gen_expand_wildcards(1, buff_list, &filecount, &files,
-          EW_FILE|EW_SILENT) == FAIL
-      || filecount == 0) {
-    EMSG2("E151: No match: %s", NameBuff);
-    xfree(dirname);
-    return;
-  }
-
-  /* Go over all files in the directory to find out what languages are
-   * present. */
-  ga_init(&ga, 1, 10);
-  for (int i = 0; i < filecount; ++i) {
-    len = (int)STRLEN(files[i]);
-    if (len <= 4) {
-      continue;
-    }
-    if (STRICMP(files[i] + len - 4, ".txt") == 0) {
-      /* ".txt" -> language "en" */
-      lang[0] = 'e';
-      lang[1] = 'n';
-    } else if (files[i][len - 4] == '.'
-               && ASCII_ISALPHA(files[i][len - 3])
-               && ASCII_ISALPHA(files[i][len - 2])
-               && TOLOWER_ASC(files[i][len - 1]) == 'x') {
-      /* ".abx" -> language "ab" */
-      lang[0] = TOLOWER_ASC(files[i][len - 3]);
-      lang[1] = TOLOWER_ASC(files[i][len - 2]);
-    } else
-      continue;
-
-    int j;
-    /* Did we find this language already? */
-    for (j = 0; j < ga.ga_len; j += 2)
-      if (STRNCMP(lang, ((char_u *)ga.ga_data) + j, 2) == 0)
-        break;
-    if (j == ga.ga_len) {
-      /* New language, add it. */
-      ga_grow(&ga, 2);
-      ((char_u *)ga.ga_data)[ga.ga_len++] = lang[0];
-      ((char_u *)ga.ga_data)[ga.ga_len++] = lang[1];
-    }
-  }
-
-  /*
-   * Loop over the found languages to generate a tags file for each one.
-   */
-  for (int j = 0; j < ga.ga_len; j += 2) {
-    STRCPY(fname, "tags-xx");
-    fname[5] = ((char_u *)ga.ga_data)[j];
-    fname[6] = ((char_u *)ga.ga_data)[j + 1];
-    if (fname[5] == 'e' && fname[6] == 'n') {
-      /* English is an exception: use ".txt" and "tags". */
-      fname[4] = NUL;
-      STRCPY(ext, ".txt");
-    } else {
-      /* Language "ab" uses ".abx" and "tags-ab". */
-      STRCPY(ext, ".xxx");
-      ext[1] = fname[5];
-      ext[2] = fname[6];
-    }
-    helptags_one(dirname, ext, fname, add_help_tags);
-  }
-
-  ga_clear(&ga);
-  FreeWild(filecount, files);
-
-  xfree(dirname);
-}
-
-static void 
-helptags_one (
-    char_u *dir,               /* doc directory */
-    char_u *ext,               /* suffix, ".txt", ".itx", ".frx", etc. */
-    char_u *tagfname,          /* "tags" for English, "tags-fr" for French. */
-    int add_help_tags              /* add "help-tags" tag */
-)
+/// Generate tags in one help directory
+///
+/// @param dir  Path to the doc directory
+/// @param ext  Suffix of the help files (".txt", ".itx", ".frx", etc.)
+/// @param tagname  Name of the tags file ("tags" for English, "tags-fr" for
+///                 French)
+/// @param add_help_tags  Whether to add the "help-tags" tag
+static void helptags_one(char_u *dir, char_u *ext, char_u *tagfname,
+                         bool add_help_tags)
 {
   FILE        *fd_tags;
   FILE        *fd;
@@ -5111,6 +5004,132 @@ helptags_one (
   fclose(fd_tags);          /* there is no check for an error... */
 }
 
+/// Generate tags in one help directory, taking care of translations.
+static void do_helptags(char_u *dirname, bool add_help_tags)
+{
+  int len;
+  garray_T ga;
+  char_u lang[2];
+  char_u ext[5];
+  char_u fname[8];
+  int filecount;
+  char_u **files;
+
+  // Get a list of all files in the help directory and in subdirectories.
+  STRCPY(NameBuff, dirname);
+  add_pathsep((char *)NameBuff);
+  STRCAT(NameBuff, "**");
+
+  // Note: We cannot just do `&NameBuff` because it is a statically sized array
+  //       so `NameBuff == &NameBuff` according to C semantics.
+  char_u *buff_list[1] = {NameBuff};
+  if (gen_expand_wildcards(1, buff_list, &filecount, &files,
+                           EW_FILE|EW_SILENT) == FAIL
+      || filecount == 0) {
+    EMSG2("E151: No match: %s", NameBuff);
+    xfree(dirname);
+    return;
+  }
+
+  /* Go over all files in the directory to find out what languages are
+   * present. */
+  int j;
+  ga_init(&ga, 1, 10);
+  for (int i = 0; i < filecount; i++) {
+    len = (int)STRLEN(files[i]);
+    if (len <= 4) {
+      continue;
+    }
+    if (STRICMP(files[i] + len - 4, ".txt") == 0) {
+      /* ".txt" -> language "en" */
+      lang[0] = 'e';
+      lang[1] = 'n';
+    } else if (files[i][len - 4] == '.'
+               && ASCII_ISALPHA(files[i][len - 3])
+               && ASCII_ISALPHA(files[i][len - 2])
+               && TOLOWER_ASC(files[i][len - 1]) == 'x') {
+      /* ".abx" -> language "ab" */
+      lang[0] = TOLOWER_ASC(files[i][len - 3]);
+      lang[1] = TOLOWER_ASC(files[i][len - 2]);
+    } else
+      continue;
+
+    // Did we find this language already?
+    for (j = 0; j < ga.ga_len; j += 2) {
+      if (STRNCMP(lang, ((char_u *)ga.ga_data) + j, 2) == 0) {
+        break;
+      }
+    }
+    if (j == ga.ga_len) {
+      // New language, add it.
+      ga_grow(&ga, 2);
+      ((char_u *)ga.ga_data)[ga.ga_len++] = lang[0];
+      ((char_u *)ga.ga_data)[ga.ga_len++] = lang[1];
+    }
+  }
+
+  /*
+   * Loop over the found languages to generate a tags file for each one.
+   */
+  for (j = 0; j < ga.ga_len; j += 2) {
+    STRCPY(fname, "tags-xx");
+    fname[5] = ((char_u *)ga.ga_data)[j];
+    fname[6] = ((char_u *)ga.ga_data)[j + 1];
+    if (fname[5] == 'e' && fname[6] == 'n') {
+      /* English is an exception: use ".txt" and "tags". */
+      fname[4] = NUL;
+      STRCPY(ext, ".txt");
+    } else {
+      /* Language "ab" uses ".abx" and "tags-ab". */
+      STRCPY(ext, ".xxx");
+      ext[1] = fname[5];
+      ext[2] = fname[6];
+    }
+    helptags_one(dirname, ext, fname, add_help_tags);
+  }
+
+  ga_clear(&ga);
+  FreeWild(filecount, files);
+}
+
+    static void
+helptags_cb(char_u *fname, void *cookie)
+{
+    do_helptags(fname, *(bool *)cookie);
+}
+
+/*
+ * ":helptags"
+ */
+void ex_helptags(exarg_T *eap)
+{
+  expand_T xpc;
+  char_u *dirname;
+  bool add_help_tags = false;
+
+  /* Check for ":helptags ++t {dir}". */
+  if (STRNCMP(eap->arg, "++t", 3) == 0 && ascii_iswhite(eap->arg[3])) {
+    add_help_tags = true;
+    eap->arg = skipwhite(eap->arg + 3);
+  }
+
+  if (STRCMP(eap->arg, "ALL") == 0) {
+    do_in_path(p_rtp, (char_u *)"doc", DIP_ALL + DIP_DIR,
+               helptags_cb, &add_help_tags);
+  } else {
+    ExpandInit(&xpc);
+    xpc.xp_context = EXPAND_DIRECTORIES;
+    dirname = ExpandOne(&xpc, eap->arg, NULL,
+                        WILD_LIST_NOTFOUND|WILD_SILENT, WILD_EXPAND_FREE);
+    if (dirname == NULL || !os_isdir(dirname)) {
+      EMSG2(_("E150: Not a directory: %s"), eap->arg);
+    } else {
+      do_helptags(dirname, add_help_tags);
+    }
+    xfree(dirname);
+  }
+}
+
 struct sign
 {
     sign_T      *sn_next;       /* next sign in list */
diff --git a/src/nvim/ex_cmds.lua b/src/nvim/ex_cmds.lua
index 6c58879d58..76191d5a56 100644
--- a/src/nvim/ex_cmds.lua
+++ b/src/nvim/ex_cmds.lua
@@ -1849,6 +1849,18 @@ return {
     func='ex_print',
   },
   {
+    command='packadd',
+    flags=bit.bor(BANG, FILE1, NEEDARG, TRLBAR, SBOXOK, CMDWIN),
+    addr_type=ADDR_LINES,
+    func='ex_packadd',
+  },
+  {
+    command='packloadall',
+    flags=bit.bor(BANG, TRLBAR, SBOXOK, CMDWIN),
+    addr_type=ADDR_LINES,
+    func='ex_packloadall',
+  },
+  {
     command='pclose',
     flags=bit.bor(BANG, TRLBAR),
     addr_type=ADDR_LINES,
diff --git a/src/nvim/ex_cmds2.c b/src/nvim/ex_cmds2.c
index 40074f726c..b56b1cf013 100644
--- a/src/nvim/ex_cmds2.c
+++ b/src/nvim/ex_cmds2.c
@@ -2237,7 +2237,7 @@ void ex_compiler(exarg_T *eap)
     do_unlet((char_u *)"b:current_compiler", true);
 
     snprintf((char *)buf, bufsize, "compiler/%s.vim", eap->arg);
-    if (source_runtime(buf, true) == FAIL) {
+    if (source_runtime(buf, DIP_ALL) == FAIL) {
       EMSG2(_("E666: compiler not supported: %s"), eap->arg);
     }
     xfree(buf);
@@ -2263,10 +2263,29 @@ void ex_compiler(exarg_T *eap)
   }
 }
 
-/// ":runtime {name}"
+/// ":runtime [what] {name}"
 void ex_runtime(exarg_T *eap)
 {
-  source_runtime(eap->arg, eap->forceit);
+  char_u *arg = eap->arg;
+  char_u *p = skiptowhite(arg);
+  ptrdiff_t len = p - arg;
+  int flags = eap->forceit ? DIP_ALL : 0;
+
+  if (STRNCMP(arg, "START", len) == 0) {
+    flags += DIP_START + DIP_NORTP;
+    arg = skipwhite(arg + len);
+  } else if (STRNCMP(arg, "OPT", len) == 0) {
+    flags += DIP_OPT + DIP_NORTP;
+    arg = skipwhite(arg + len);
+  } else if (STRNCMP(arg, "PACK", len) == 0) {
+    flags += DIP_START + DIP_OPT + DIP_NORTP;
+    arg = skipwhite(arg + len);
+  } else if (STRNCMP(arg, "ALL", len) == 0) {
+    flags += DIP_START + DIP_OPT;
+    arg = skipwhite(arg + len);
+  }
+
+  source_runtime(arg, flags);
 }
 
 
@@ -2277,28 +2296,25 @@ static void source_callback(char_u *fname, void *cookie)
 
 /// Source the file "name" from all directories in 'runtimepath'.
 /// "name" can contain wildcards.
-/// When "all" is true, source all files, otherwise only the first one.
+/// When "flags" has DIP_ALL: source all files, otherwise only the first one.
+///
 /// return FAIL when no file could be sourced, OK otherwise.
-int source_runtime(char_u *name, int all)
+int source_runtime(char_u *name, int flags)
 {
-  return do_in_runtimepath(name, all, source_callback, NULL);
+  return do_in_runtimepath(name, flags, source_callback, NULL);
 }
 
-/// Find "name" in 'runtimepath'.  When found, invoke the callback function for
-/// it: callback(fname, "cookie")
-/// When "all" is true repeat for all matches, otherwise only the first one is
-/// used.
-/// Returns OK when at least one match found, FAIL otherwise.
-/// If "name" is NULL calls callback for each entry in runtimepath. Cookie is
-/// passed by reference in this case, setting it to NULL indicates that callback
-/// has done its job.
-int do_in_runtimepath(char_u *name, int all, DoInRuntimepathCB callback,
-                      void *cookie)
+/// Find the file "name" in all directories in "path" and invoke
+/// "callback(fname, cookie)".
+/// "name" can contain wildcards.
+/// When "flags" has DIP_ALL: source all files, otherwise only the first one.
+/// When "flags" has DIP_DIR: find directories instead of files.
+/// When "flags" has DIP_ERR: give an error message if there is no match.
+///
+/// return FAIL when no file could be sourced, OK otherwise.
+int do_in_path(char_u *path, char_u *name, int flags,
+               DoInRuntimepathCB callback, void *cookie)
 {
-  char_u      *rtp;
-  char_u      *np;
-  char_u      *buf;
-  char_u      *rtp_copy;
   char_u      *tail;
   int num_files;
   char_u      **files;
@@ -2307,19 +2323,19 @@ int do_in_runtimepath(char_u *name, int all, DoInRuntimepathCB callback,
 
   // Make a copy of 'runtimepath'.  Invoking the callback may change the
   // value.
-  rtp_copy = vim_strsave(p_rtp);
-  buf = xmallocz(MAXPATHL);
+  char_u *rtp_copy = vim_strsave(path);
+  char_u *buf = xmallocz(MAXPATHL);
   {
     if (p_verbose > 1 && name != NULL) {
       verbose_enter();
       smsg(_("Searching for \"%s\" in \"%s\""),
-           (char *)name, (char *)p_rtp);
+           (char *)name, (char *)path);
       verbose_leave();
     }
 
     // Loop over all entries in 'runtimepath'.
-    rtp = rtp_copy;
-    while (*rtp != NUL && (all || !did_one)) {
+    char_u *rtp = rtp_copy;
+    while (*rtp != NUL && ((flags & DIP_ALL) || !did_one)) {
       // Copy the path from 'runtimepath' to buf[].
       copy_option_part(&rtp, buf, MAXPATHL, ",");
       if (name == NULL) {
@@ -2332,8 +2348,8 @@ int do_in_runtimepath(char_u *name, int all, DoInRuntimepathCB callback,
         tail = buf + STRLEN(buf);
 
         // Loop over all patterns in "name"
-        np = name;
-        while (*np != NUL && (all || !did_one)) {
+        char_u *np = name;
+        while (*np != NUL && ((flags & DIP_ALL) || !did_one)) {
           // Append the pattern from "name" to buf[].
           assert(MAXPATHL >= (tail - buf));
           copy_option_part(&np, tail, (size_t)(MAXPATHL - (tail - buf)),
@@ -2347,11 +2363,12 @@ int do_in_runtimepath(char_u *name, int all, DoInRuntimepathCB callback,
 
           // Expand wildcards, invoke the callback for each match.
           if (gen_expand_wildcards(1, &buf, &num_files, &files,
-                                   EW_FILE) == OK) {
+                                   (flags & DIP_DIR) ? EW_DIR
+                                                     : EW_FILE) == OK) {
             for (i = 0; i < num_files; i++) {
               (*callback)(files[i], cookie);
               did_one = true;
-              if (!all) {
+              if (!(flags & DIP_ALL)) {
                 break;
               }
             }
@@ -2363,16 +2380,228 @@ int do_in_runtimepath(char_u *name, int all, DoInRuntimepathCB callback,
   }
   xfree(buf);
   xfree(rtp_copy);
-  if (p_verbose > 0 && !did_one && name != NULL) {
-    verbose_enter();
-    smsg(_("not found in 'runtimepath': \"%s\""), name);
-    verbose_leave();
+  if (!did_one && name != NULL) {
+    char *basepath = path == p_rtp ? "runtimepath" : "packpath";
+
+    if (flags & DIP_ERR) {
+      EMSG3(_(e_dirnotf), basepath, name);
+    } else if (p_verbose > 0) {
+      verbose_enter();
+      smsg(_("not found in '%s': \"%s\""), basepath, name);
+      verbose_leave();
+    }
   }
 
 
   return did_one ? OK : FAIL;
 }
 
+/// Find "name" in 'runtimepath'.  When found, invoke the callback function for
+/// it: callback(fname, "cookie")
+/// When "flags" has DIP_ALL repeat for all matches, otherwise only the first
+/// one is used.
+/// Returns OK when at least one match found, FAIL otherwise.
+/// If "name" is NULL calls callback for each entry in runtimepath. Cookie is
+/// passed by reference in this case, setting it to NULL indicates that callback
+/// has done its job.
+int do_in_runtimepath(char_u *name, int flags, DoInRuntimepathCB callback,
+                      void *cookie)
+{
+  int done = FAIL;
+
+  if ((flags & DIP_NORTP) == 0) {
+    done = do_in_path(p_rtp, name, flags, callback, cookie);
+  }
+
+  if ((done == FAIL || (flags & DIP_ALL)) && (flags & DIP_START)) {
+    char *start_dir = "pack/*/start/*/%s";  // NOLINT
+    size_t len = STRLEN(start_dir) + STRLEN(name);
+    char_u *s = xmallocz(len);
+
+    vim_snprintf((char *)s, len, start_dir, name);
+    done = do_in_path(p_pp, s, flags, callback, cookie);
+
+    xfree(s);
+  }
+
+  if ((done == FAIL || (flags & DIP_ALL)) && (flags & DIP_OPT)) {
+    char *opt_dir = "pack/*/opt/*/%s";  // NOLINT
+    size_t len = STRLEN(opt_dir) + STRLEN(name);
+    char_u *s = xmallocz(len);
+
+    vim_snprintf((char *)s, len, opt_dir, name);
+    done = do_in_path(p_pp, s, flags, callback, cookie);
+
+    xfree(s);
+  }
+
+  return done;
+}
+
+// Expand wildcards in "pat" and invoke do_source() for each match.
+static void source_all_matches(char_u *pat)
+{
+  int num_files;
+  char_u **files;
+
+  if (gen_expand_wildcards(1, &pat, &num_files, &files, EW_FILE) == OK) {
+    for (int i = 0; i < num_files; i++) {
+      (void)do_source(files[i], false, DOSO_NONE);
+    }
+    FreeWild(num_files, files);
+  }
+}
+
+// used for "cookie" of add_pack_plugin()
+static int APP_ADD_DIR;
+static int APP_LOAD;
+static int APP_BOTH;
+
+static void add_pack_plugin(char_u *fname, void *cookie)
+{
+  char_u *p4, *p3, *p2, *p1, *p;
+  char_u *new_rtp;
+  char_u *ffname = (char_u *)fix_fname((char *)fname);
+
+  if (ffname == NULL) {
+    return;
+  }
+
+  if (cookie != &APP_LOAD && strstr((char *)p_rtp, (char *)ffname) == NULL) {
+    // directory is not yet in 'runtimepath', add it
+    p4 = p3 = p2 = p1 = get_past_head(ffname);
+    for (p = p1; *p; mb_ptr_adv(p)) {
+      if (vim_ispathsep_nocolon(*p)) {
+        p4 = p3; p3 = p2; p2 = p1; p1 = p;
+      }
+    }
+
+    // now we have:
+    // rtp/pack/name/start/name
+    //    p4   p3   p2   p1
+    //
+    // find the part up to "pack" in 'runtimepath'
+    char_u c = *p4;
+    *p4 = NUL;
+
+    // Find "ffname" in "p_rtp", ignoring '/' vs '\' differences
+    size_t fname_len = STRLEN(ffname);
+    char_u *insp = p_rtp;
+    for (;;) {
+      if (vim_fnamencmp(insp, ffname, fname_len) == 0) {
+        break;
+      }
+      insp = vim_strchr(insp, ',');
+      if (insp == NULL) {
+        break;
+      }
+      insp++;
+    }
+
+    if (insp == NULL) {
+      // not found, append at the end
+      insp = p_rtp + STRLEN(p_rtp);
+    } else {
+      // append after the matching directory.
+      insp += STRLEN(ffname);
+      while (*insp != NUL && *insp != ',') {
+        insp++;
+      }
+    }
+    *p4 = c;
+
+    // check if rtp/pack/name/start/name/after exists
+    char *afterdir = concat_fnames((char *)ffname, "after", true);
+    size_t afterlen = 0;
+    if (os_isdir((char_u *)afterdir)) {
+      afterlen = STRLEN(afterdir) + 1;  // add one for comma
+    }
+
+    size_t oldlen = STRLEN(p_rtp);
+    size_t addlen = STRLEN(ffname) + 1;  // add one for comma
+    new_rtp = try_malloc(oldlen + addlen + afterlen + 1);  // add one for NUL
+    if (new_rtp == NULL) {
+      goto theend;
+    }
+    uintptr_t keep = (uintptr_t)(insp - p_rtp);
+    memmove(new_rtp, p_rtp, keep);
+    new_rtp[keep] = ',';
+    memmove(new_rtp + keep + 1, ffname, addlen);
+    if (p_rtp[keep] != NUL) {
+      memmove(new_rtp + keep + addlen, p_rtp + keep,
+              oldlen - keep + 1);
+    }
+    if (afterlen > 0) {
+      STRCAT(new_rtp, ",");
+      STRCAT(new_rtp, afterdir);
+    }
+    set_option_value((char_u *)"rtp", 0L, new_rtp, 0);
+    xfree(new_rtp);
+    xfree(afterdir);
+  }
+
+  if (cookie != &APP_ADD_DIR) {
+    static const char *plugpat = "%s/plugin/*.vim";  // NOLINT
+    static const char *ftpat = "%s/ftdetect/*.vim";  // NOLINT
+
+    size_t len = STRLEN(ffname) + STRLEN(ftpat);
+    char_u *pat = try_malloc(len + 1);
+    if (pat == NULL) {
+      goto theend;
+    }
+    vim_snprintf((char *)pat, len, plugpat, ffname);
+    source_all_matches(pat);
+
+    char_u *cmd = vim_strsave((char_u *)"g:did_load_filetypes");
+
+    // If runtime/filetype.vim wasn't loaded yet, the scripts will be
+    // found when it loads.
+    if (eval_to_number(cmd) > 0) {
+      do_cmdline_cmd("augroup filetypedetect");
+      vim_snprintf((char *)pat, len, ftpat, ffname);
+      source_all_matches(pat);
+      do_cmdline_cmd("augroup END");
+    }
+    xfree(cmd);
+    xfree(pat);
+  }
+
+theend:
+  xfree(ffname);
+}
+
+static bool did_source_packages = false;
+
+// ":packloadall"
+// Find plugins in the package directories and source them.
+void ex_packloadall(exarg_T *eap)
+{
+  if (!did_source_packages || (eap != NULL && eap->forceit)) {
+    did_source_packages = true;
+
+    // First do a round to add all directories to 'runtimepath', then load
+    // the plugins. This allows for plugins to use an autoload directory
+    // of another plugin.
+    do_in_path(p_pp, (char_u *)"pack/*/start/*", DIP_ALL + DIP_DIR,  // NOLINT
+               add_pack_plugin, &APP_ADD_DIR);
+    do_in_path(p_pp, (char_u *)"pack/*/start/*", DIP_ALL + DIP_DIR,  // NOLINT
+               add_pack_plugin, &APP_LOAD);
+  }
+}
+
+/// ":packadd[!] {name}"
+void ex_packadd(exarg_T *eap)
+{
+  static const char *plugpat = "pack/*/opt/%s";  // NOLINT
+
+  size_t len = STRLEN(plugpat) + STRLEN(eap->arg);
+  char *pat = (char *)xmallocz(len);
+  vim_snprintf(pat, len, plugpat, eap->arg);
+  do_in_path(p_pp, (char_u *)pat, DIP_ALL + DIP_DIR + DIP_ERR, add_pack_plugin,
+             eap->forceit ? &APP_ADD_DIR : &APP_BOTH);
+  xfree(pat);
+}
+
 /// ":options"
 void ex_options(exarg_T *eap)
 {
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index ad17d4dcbd..9bc7ec39da 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -3316,6 +3316,11 @@ set_one_cmd_context (
     xp->xp_pattern = arg;
     break;
 
+  case CMD_packadd:
+    xp->xp_context = EXPAND_PACKADD;
+    xp->xp_pattern = arg;
+    break;
+
 #ifdef HAVE_WORKING_LIBINTL
   case CMD_language:
     p = skiptowhite(arg);
@@ -4660,41 +4665,42 @@ static struct {
   char    *name;
 } command_complete[] =
 {
-  {EXPAND_AUGROUP, "augroup"},
-  {EXPAND_BEHAVE, "behave"},
-  {EXPAND_BUFFERS, "buffer"},
-  {EXPAND_COLORS, "color"},
-  {EXPAND_COMMANDS, "command"},
-  {EXPAND_COMPILER, "compiler"},
-  {EXPAND_CSCOPE, "cscope"},
-  {EXPAND_USER_DEFINED, "custom"},
-  {EXPAND_USER_LIST, "customlist"},
-  {EXPAND_DIRECTORIES, "dir"},
-  {EXPAND_ENV_VARS, "environment"},
-  {EXPAND_EVENTS, "event"},
-  {EXPAND_EXPRESSION, "expression"},
-  {EXPAND_FILES, "file"},
-  {EXPAND_FILES_IN_PATH, "file_in_path"},
-  {EXPAND_FILETYPE, "filetype"},
-  {EXPAND_FUNCTIONS, "function"},
-  {EXPAND_HELP, "help"},
-  {EXPAND_HIGHLIGHT, "highlight"},
-  {EXPAND_HISTORY, "history"},
+  { EXPAND_AUGROUP, "augroup" },
+  { EXPAND_BEHAVE, "behave" },
+  { EXPAND_BUFFERS, "buffer" },
+  { EXPAND_COLORS, "color" },
+  { EXPAND_COMMANDS, "command" },
+  { EXPAND_COMPILER, "compiler" },
+  { EXPAND_CSCOPE, "cscope" },
+  { EXPAND_USER_DEFINED, "custom" },
+  { EXPAND_USER_LIST, "customlist" },
+  { EXPAND_DIRECTORIES, "dir" },
+  { EXPAND_ENV_VARS, "environment" },
+  { EXPAND_EVENTS, "event" },
+  { EXPAND_EXPRESSION, "expression" },
+  { EXPAND_FILES, "file" },
+  { EXPAND_FILES_IN_PATH, "file_in_path" },
+  { EXPAND_FILETYPE, "filetype" },
+  { EXPAND_FUNCTIONS, "function" },
+  { EXPAND_HELP, "help" },
+  { EXPAND_HIGHLIGHT, "highlight" },
+  { EXPAND_HISTORY, "history" },
 #ifdef HAVE_WORKING_LIBINTL
-  {EXPAND_LOCALES, "locale"},
+  { EXPAND_LOCALES, "locale" },
 #endif
-  {EXPAND_MAPPINGS, "mapping"},
-  {EXPAND_MENUS, "menu"},
-  {EXPAND_OWNSYNTAX, "syntax"},
-  {EXPAND_SYNTIME, "syntime"},
-  {EXPAND_SETTINGS, "option"},
-  {EXPAND_SHELLCMD, "shellcmd"},
-  {EXPAND_SIGN, "sign"},
-  {EXPAND_TAGS, "tag"},
-  {EXPAND_TAGS_LISTFILES, "tag_listfiles"},
-  {EXPAND_USER, "user"},
-  {EXPAND_USER_VARS, "var"},
-  {0, NULL}
+  { EXPAND_MAPPINGS, "mapping" },
+  { EXPAND_MENUS, "menu" },
+  { EXPAND_OWNSYNTAX, "syntax" },
+  { EXPAND_SYNTIME, "syntime" },
+  { EXPAND_SETTINGS, "option" },
+  { EXPAND_PACKADD, "packadd" },
+  { EXPAND_SHELLCMD, "shellcmd" },
+  { EXPAND_SIGN, "sign" },
+  { EXPAND_TAGS, "tag" },
+  { EXPAND_TAGS_LISTFILES, "tag_listfiles" },
+  { EXPAND_USER, "user" },
+  { EXPAND_USER_VARS, "var" },
+  { 0, NULL }
 };
 
 static void uc_list(char_u *name, size_t name_len)
@@ -9330,14 +9336,14 @@ static void ex_filetype(exarg_T *eap)
   }
   if (STRCMP(arg, "on") == 0 || STRCMP(arg, "detect") == 0) {
     if (*arg == 'o' || !filetype_detect) {
-      source_runtime((char_u *)FILETYPE_FILE, true);
+      source_runtime((char_u *)FILETYPE_FILE, DIP_ALL);
       filetype_detect = kTrue;
       if (plugin) {
-        source_runtime((char_u *)FTPLUGIN_FILE, true);
+        source_runtime((char_u *)FTPLUGIN_FILE, DIP_ALL);
         filetype_plugin = kTrue;
       }
       if (indent) {
-        source_runtime((char_u *)INDENT_FILE, true);
+        source_runtime((char_u *)INDENT_FILE, DIP_ALL);
         filetype_indent = kTrue;
       }
     }
@@ -9348,15 +9354,15 @@ static void ex_filetype(exarg_T *eap)
   } else if (STRCMP(arg, "off") == 0) {
     if (plugin || indent) {
       if (plugin) {
-        source_runtime((char_u *)FTPLUGOF_FILE, true);
+        source_runtime((char_u *)FTPLUGOF_FILE, DIP_ALL);
         filetype_plugin = kFalse;
       }
       if (indent) {
-        source_runtime((char_u *)INDOFF_FILE, true);
+        source_runtime((char_u *)INDOFF_FILE, DIP_ALL);
         filetype_indent = kFalse;
       }
     } else {
-      source_runtime((char_u *)FTOFF_FILE, true);
+      source_runtime((char_u *)FTOFF_FILE, DIP_ALL);
       filetype_detect = kFalse;
     }
   } else
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 65144dace8..cd28554970 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -3440,6 +3440,7 @@ addstar (
         || context == EXPAND_COMPILER
         || context == EXPAND_OWNSYNTAX
         || context == EXPAND_FILETYPE
+        || context == EXPAND_PACKADD
         || (context == EXPAND_TAGS && fname[0] == '/'))
       retval = vim_strnsave(fname, len);
     else {
@@ -3794,23 +3795,27 @@ ExpandFromContext (
       || xp->xp_context == EXPAND_TAGS_LISTFILES)
     return expand_tags(xp->xp_context == EXPAND_TAGS, pat, num_file, file);
   if (xp->xp_context == EXPAND_COLORS) {
-    char *directories[] = {"colors", NULL};
-    return ExpandRTDir(pat, num_file, file, directories);
+    char *directories[] = { "colors", NULL };
+    return ExpandRTDir(pat, DIP_START + DIP_OPT, num_file, file, directories);
   }
   if (xp->xp_context == EXPAND_COMPILER) {
-    char *directories[] = {"compiler", NULL};
-    return ExpandRTDir(pat, num_file, file, directories);
+    char *directories[] = { "compiler", NULL };
+    return ExpandRTDir(pat, 0, num_file, file, directories);
   }
   if (xp->xp_context == EXPAND_OWNSYNTAX) {
-    char *directories[] = {"syntax", NULL};
-    return ExpandRTDir(pat, num_file, file, directories);
+    char *directories[] = { "syntax", NULL };
+    return ExpandRTDir(pat, 0, num_file, file, directories);
   }
   if (xp->xp_context == EXPAND_FILETYPE) {
-    char *directories[] = {"syntax", "indent", "ftplugin", NULL};
-    return ExpandRTDir(pat, num_file, file, directories);
+    char *directories[] = { "syntax", "indent", "ftplugin", NULL };
+    return ExpandRTDir(pat, 0, num_file, file, directories);
   }
-  if (xp->xp_context == EXPAND_USER_LIST)
+  if (xp->xp_context == EXPAND_USER_LIST) {
     return ExpandUserList(xp, num_file, file);
+  }
+  if (xp->xp_context == EXPAND_PACKADD) {
+    return ExpandPackAddDir(pat, num_file, file);
+  }
 
   regmatch.regprog = vim_regcomp(pat, p_magic ? RE_MAGIC : 0);
   if (regmatch.regprog == NULL)
@@ -4190,12 +4195,16 @@ static int ExpandUserList(expand_T *xp, int *num_file, char_u ***file)
   return OK;
 }
 
-/*
- * Expand color scheme, compiler or filetype names:
- * 'runtimepath'/{dirnames}/{pat}.vim
- * "dirnames" is an array with one or more directory names.
- */
-static int ExpandRTDir(char_u *pat, int *num_file, char_u ***file, char *dirnames[])
+/// Expand color scheme, compiler or filetype names.
+/// Search from 'runtimepath':
+///   'runtimepath'/{dirnames}/{pat}.vim
+/// When "flags" has DIP_START: search also from 'start' of 'packpath':
+///   'packpath'/pack/ * /start/ * /{dirnames}/{pat}.vim
+/// When "flags" has DIP_OPT: search also from 'opt' of 'packpath':
+///   'packpath'/pack/ * /opt/ * /{dirnames}/{pat}.vim
+/// "dirnames" is an array with one or more directory names.
+static int ExpandRTDir(char_u *pat, int flags, int *num_file, char_u ***file,
+                       char *dirnames[])