Remove simpler cases of OOM error handling (after *alloc calls)

By simpler cases I mean cases where the OOM error is not expected to be handled
by the caller of the function that calls `alloc`, `lalloc`, `xrealloc`,
`xmalloc`, `alloc_clear`, and `lalloc_clear`.

These are the functions that:

 - Do not return an allocated buffer
 - Have OOM as the only error condition

I took note of the functions that expect the caller to handle the OOM error and
will go through them to check all the callers that may be handling OOM error in
future commits.

I'm ignoring eval.c and ex_.c in this series of commits. eval.c will soon be
obsolete and I will deal with ex_.c in later PRs.

1 files changed, 70 insertions, 96 deletions

diff --git a/src/syntax.c b/src/syntax.c
index 453ee49e4b..b1b5a80087 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -1123,8 +1123,6 @@ static void syn_stack_alloc(void)
     }
 
     sstp = (synstate_T *)alloc_clear((unsigned)(len * sizeof(synstate_T)));
-    if (sstp == NULL)           /* out of memory! */
-      return;
 
     to = sstp - 1;
     if (syn_block->b_sst_array != NULL) {
@@ -3936,8 +3934,6 @@ add_keyword (
   else
     name_ic = name;
   kp = (keyentry_T *)alloc((int)(sizeof(keyentry_T) + STRLEN(name_ic)));
-  if (kp == NULL)
-    return;
   STRCPY(kp->keyword, name_ic);
   kp->k_syn.id = id;
   kp->k_syn.inc_tag = current_syn_inc_tag;
@@ -4160,12 +4156,10 @@ static void syn_incl_toplevel(int id, int *flagsp)
     short       *grp_list = (short *)alloc((unsigned)(2 * sizeof(short)));
     int tlg_id = curwin->w_s->b_syn_topgrp - SYNID_CLUSTER;
 
-    if (grp_list != NULL) {
-      grp_list[0] = id;
-      grp_list[1] = 0;
-      syn_combine_list(&SYN_CLSTR(curwin->w_s)[tlg_id].scl_list, &grp_list,
-          CLUSTER_ADD);
-    }
+    grp_list[0] = id;
+    grp_list[1] = 0;
+    syn_combine_list(&SYN_CLSTR(curwin->w_s)[tlg_id].scl_list, &grp_list,
+        CLUSTER_ADD);
   }
 }
 
@@ -4261,77 +4255,75 @@ static void syn_cmd_keyword(exarg_T *eap, int syncing)
     if (syn_id != 0)
       /* allocate a buffer, for removing backslashes in the keyword */
       keyword_copy = alloc((unsigned)STRLEN(rest) + 1);
-    if (keyword_copy != NULL) {
-      syn_opt_arg.flags = 0;
-      syn_opt_arg.keyword = TRUE;
-      syn_opt_arg.sync_idx = NULL;
-      syn_opt_arg.has_cont_list = FALSE;
-      syn_opt_arg.cont_in_list = NULL;
-      syn_opt_arg.next_list = NULL;
+    syn_opt_arg.flags = 0;
+    syn_opt_arg.keyword = TRUE;
+    syn_opt_arg.sync_idx = NULL;
+    syn_opt_arg.has_cont_list = FALSE;
+    syn_opt_arg.cont_in_list = NULL;
+    syn_opt_arg.next_list = NULL;
 
-      /*
-       * The options given apply to ALL keywords, so all options must be
-       * found before keywords can be created.
-       * 1: collect the options and copy the keywords to keyword_copy.
-       */
-      cnt = 0;
-      p = keyword_copy;
-      for (; rest != NULL && !ends_excmd(*rest); rest = skipwhite(rest)) {
-        rest = get_syn_options(rest, &syn_opt_arg, &conceal_char);
-        if (rest == NULL || ends_excmd(*rest))
-          break;
-        /* Copy the keyword, removing backslashes, and add a NUL. */
-        while (*rest != NUL && !vim_iswhite(*rest)) {
-          if (*rest == '\\' && rest[1] != NUL)
-            ++rest;
-          *p++ = *rest++;
-        }
-        *p++ = NUL;
-        ++cnt;
+    /*
+     * The options given apply to ALL keywords, so all options must be
+     * found before keywords can be created.
+     * 1: collect the options and copy the keywords to keyword_copy.
+     */
+    cnt = 0;
+    p = keyword_copy;
+    for (; rest != NULL && !ends_excmd(*rest); rest = skipwhite(rest)) {
+      rest = get_syn_options(rest, &syn_opt_arg, &conceal_char);
+      if (rest == NULL || ends_excmd(*rest))
+        break;
+      /* Copy the keyword, removing backslashes, and add a NUL. */
+      while (*rest != NUL && !vim_iswhite(*rest)) {
+        if (*rest == '\\' && rest[1] != NUL)
+          ++rest;
+        *p++ = *rest++;
       }
+      *p++ = NUL;
+      ++cnt;
+    }
 
-      if (!eap->skip) {
-        /* Adjust flags for use of ":syn include". */
-        syn_incl_toplevel(syn_id, &syn_opt_arg.flags);
+    if (!eap->skip) {
+      /* Adjust flags for use of ":syn include". */
+      syn_incl_toplevel(syn_id, &syn_opt_arg.flags);
 
-        /*
-         * 2: Add an entry for each keyword.
-         */
-        for (kw = keyword_copy; --cnt >= 0; kw += STRLEN(kw) + 1) {
-          for (p = vim_strchr(kw, '[');; ) {
-            if (p != NULL)
-              *p = NUL;
-            add_keyword(kw, syn_id, syn_opt_arg.flags,
-                syn_opt_arg.cont_in_list,
-                syn_opt_arg.next_list, conceal_char);
-            if (p == NULL)
-              break;
-            if (p[1] == NUL) {
-              EMSG2(_("E789: Missing ']': %s"), kw);
-              kw = p + 2;                       /* skip over the NUL */
-              break;
-            }
-            if (p[1] == ']') {
-              kw = p + 1;                       /* skip over the "]" */
-              break;
-            }
-            if (has_mbyte) {
-              int l = (*mb_ptr2len)(p + 1);
+      /*
+       * 2: Add an entry for each keyword.
+       */
+      for (kw = keyword_copy; --cnt >= 0; kw += STRLEN(kw) + 1) {
+        for (p = vim_strchr(kw, '[');; ) {
+          if (p != NULL)
+            *p = NUL;
+          add_keyword(kw, syn_id, syn_opt_arg.flags,
+              syn_opt_arg.cont_in_list,
+              syn_opt_arg.next_list, conceal_char);
+          if (p == NULL)
+            break;
+          if (p[1] == NUL) {
+            EMSG2(_("E789: Missing ']': %s"), kw);
+            kw = p + 2;                       /* skip over the NUL */
+            break;
+          }
+          if (p[1] == ']') {
+            kw = p + 1;                       /* skip over the "]" */
+            break;
+          }
+          if (has_mbyte) {
+            int l = (*mb_ptr2len)(p + 1);
 
-              memmove(p, p + 1, l);
-              p += l;
-            } else {
-              p[0] = p[1];
-              ++p;
-            }
+            memmove(p, p + 1, l);
+            p += l;
+          } else {
+            p[0] = p[1];
+            ++p;
           }
         }
       }
-
-      vim_free(keyword_copy);
-      vim_free(syn_opt_arg.cont_in_list);
-      vim_free(syn_opt_arg.next_list);
     }
+
+    vim_free(keyword_copy);
+    vim_free(syn_opt_arg.cont_in_list);
+    vim_free(syn_opt_arg.next_list);
   }
 
   if (rest != NULL)
@@ -4563,17 +4555,9 @@ syn_cmd_region (
        * used from end to start).
        */
       ppp = (struct pat_ptr *)alloc((unsigned)sizeof(struct pat_ptr));
-      if (ppp == NULL) {
-        rest = NULL;
-        break;
-      }
       ppp->pp_next = pat_ptrs[item];
       pat_ptrs[item] = ppp;
       ppp->pp_synp = (synpat_T *)alloc_clear((unsigned)sizeof(synpat_T));
-      if (ppp->pp_synp == NULL) {
-        rest = NULL;
-        break;
-      }
 
       /*
        * Get the syntax pattern and the following offset(s).
@@ -4796,8 +4780,6 @@ static void syn_combine_list(short **clstr1, short **clstr2, int list_op)
         break;
       }
       clstr = (short *)alloc((unsigned)((count + 1) * sizeof(short)));
-      if (clstr == NULL)
-        break;
       clstr[count] = 0;
     }
   }
@@ -5260,10 +5242,6 @@ get_id_list (
       for (end = p; *end && !vim_iswhite(*end) && *end != ','; ++end)
         ;
       name = alloc((int)(end - p + 3));             /* leave room for "^$" */
-      if (name == NULL) {
-        failed = TRUE;
-        break;
-      }
       vim_strncpy(name + 1, p, end - p);
       if (       STRCMP(name + 1, "ALLBUT") == 0
                  || STRCMP(name + 1, "ALL") == 0
@@ -5358,8 +5336,6 @@ get_id_list (
       break;
     if (round == 1) {
       retval = (short *)alloc((unsigned)((count + 1) * sizeof(short)));
-      if (retval == NULL)
-        break;
       retval[count] = 0;            /* zero means end of the list */
       total_count = count;
     }
@@ -5395,8 +5371,7 @@ static short *copy_id_list(short *list)
     ;
   len = (count + 1) * sizeof(short);
   retval = (short *)alloc((unsigned)len);
-  if (retval != NULL)
-    memmove(retval, list, (size_t)len);
+  memmove(retval, list, (size_t)len);
 
   return retval;
 }
@@ -6208,12 +6183,11 @@ int load_colors(char_u *name)
 
   recursive = TRUE;
   buf = alloc((unsigned)(STRLEN(name) + 12));
-  if (buf != NULL) {
-    sprintf((char *)buf, "colors/%s.vim", name);
-    retval = source_runtime(buf, FALSE);
-    vim_free(buf);
-    apply_autocmds(EVENT_COLORSCHEME, name, curbuf->b_fname, FALSE, curbuf);
-  }
+  sprintf((char *)buf, "colors/%s.vim", name);
+  retval = source_runtime(buf, FALSE);
+  vim_free(buf);
+  apply_autocmds(EVENT_COLORSCHEME, name, curbuf->b_fname, FALSE, curbuf);
+
   recursive = FALSE;
 
   return retval;