vim-patch:8.0.1723: using one item array size declaration is misleading

Problem:    Using one item array size declaration is misleading.
Solution:   Instead of using "[1]" and actually using a larger array, use
            "[]".  This is to verify that this C99 feature works for all
            compilers.
https://github.com/vim/vim/commit/f3a411783c9736645d6ba480c5ff9d861164c040

The following patch is N/A because Neovim requires C99.
vim-patch:8.0.1735: flexible array member feature not supported by HP-UX

2 files changed, 53 insertions, 44 deletions

diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index 69cefe2247..4b0e680c25 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -133,14 +133,14 @@ typedef struct buffheader buffheader_T;
  */
 struct buffblock {
   buffblock_T *b_next;  // pointer to next buffblock
-  char_u b_str[1];      // contents (actually longer)
+  char_u b_str[];       // contents (flexible array)
 };
 
 /*
  * header used for the stuff buffer and the redo buffer
  */
 struct buffheader {
-  buffblock_T bh_first;  // first (dummy) block of list
+  buffblock_T *bh_first;  // first block of the list
   buffblock_T *bh_curr;  // buffblock for appending
   size_t bh_index;          // index for reading
   size_t bh_space;          // space in bh_curr for appending
diff --git a/src/nvim/getchar.c b/src/nvim/getchar.c
index 13700328fd..465c41457a 100644
--- a/src/nvim/getchar.c
+++ b/src/nvim/getchar.c
@@ -77,15 +77,15 @@ FileDescriptor *scriptin[NSCRIPT] = { NULL };
 
 #define MINIMAL_SIZE 20                 /* minimal size for b_str */
 
-static buffheader_T redobuff = { { NULL, { NUL } }, NULL, 0, 0 };
-static buffheader_T old_redobuff = { { NULL, { NUL } }, NULL, 0, 0 };
-static buffheader_T recordbuff = { { NULL, { NUL } }, NULL, 0, 0 };
+static buffheader_T redobuff = { NULL, NULL, 0, 0 };
+static buffheader_T old_redobuff = { NULL, NULL, 0, 0 };
+static buffheader_T recordbuff = { NULL, NULL, 0, 0 };
 
 // First read ahead buffer. Used for translated commands.
-static buffheader_T readbuf1 = {{NULL, {NUL}}, NULL, 0, 0};
+static buffheader_T readbuf1 = { NULL, NULL, 0, 0 };
 
 // Second read ahead buffer. Used for redo.
-static buffheader_T readbuf2 = {{NULL, {NUL}}, NULL, 0, 0};
+static buffheader_T readbuf2 = { NULL, NULL, 0, 0 };
 
 static int typeahead_char = 0;          /* typeahead char that's not flushed */
 
@@ -163,11 +163,12 @@ void free_buff(buffheader_T *buf)
 {
   buffblock_T    *p, *np;
 
-  for (p = buf->bh_first.b_next; p != NULL; p = np) {
+  for (p = buf->bh_first; p != NULL; p = np) {
     np = p->b_next;
     xfree(p);
   }
-  buf->bh_first.b_next = NULL;
+  buf->bh_first = NULL;
+  buf->bh_curr = NULL;
 }
 
 /*
@@ -181,18 +182,21 @@ static char_u *get_buffcont(buffheader_T *buffer,
   size_t count = 0;
   char_u          *p = NULL;
   char_u          *p2;
-  char_u          *str;
 
-  /* compute the total length of the string */
-  for (buffblock_T *bp = buffer->bh_first.b_next; bp != NULL; bp = bp->b_next)
+  // compute the total length of the string
+  for (const buffblock_T *bp = buffer->bh_first; bp != NULL; bp = bp->b_next) {
     count += STRLEN(bp->b_str);
+  }
 
   if (count || dozero) {
     p = xmalloc(count + 1);
     p2 = p;
-    for (buffblock_T *bp = buffer->bh_first.b_next; bp != NULL; bp = bp->b_next)
-      for (str = bp->b_str; *str; )
+    for (const buffblock_T *bp = buffer->bh_first;
+         bp != NULL; bp = bp->b_next) {
+      for (const char_u *str = bp->b_str; *str;) {
         *p2++ = *str++;
+      }
+    }
     *p2 = NUL;
   }
   return p;
@@ -257,16 +261,16 @@ static void add_buff(buffheader_T *const buf, const char *const s,
     return;
   }
 
-  if (buf->bh_first.b_next == NULL) {  // first add to list
+  if (buf->bh_first == NULL) {  // first add to list
     buf->bh_space = 0;
-    buf->bh_curr = &(buf->bh_first);
+    buf->bh_curr = NULL;
   } else if (buf->bh_curr == NULL) {  // buffer has already been read
     IEMSG(_("E222: Add to read buffer"));
     return;
   } else if (buf->bh_index != 0) {
-    memmove(buf->bh_first.b_next->b_str,
-            buf->bh_first.b_next->b_str + buf->bh_index,
-            STRLEN(buf->bh_first.b_next->b_str + buf->bh_index) + 1);
+    memmove(buf->bh_first->b_str,
+            buf->bh_first->b_str + buf->bh_index,
+            STRLEN(buf->bh_first->b_str + buf->bh_index) + 1);
   }
   buf->bh_index = 0;
 
@@ -281,13 +285,19 @@ static void add_buff(buffheader_T *const buf, const char *const s,
     } else {
       len = (size_t)slen;
     }
-    buffblock_T *p = xmalloc(sizeof(buffblock_T) + len);
+    buffblock_T *p = xmalloc(sizeof(buffblock_T) + len + 1);
     buf->bh_space = len - (size_t)slen;
     STRLCPY(p->b_str, s, slen + 1);
 
-    p->b_next = buf->bh_curr->b_next;
-    buf->bh_curr->b_next = p;
-    buf->bh_curr = p;
+    if (buf->bh_curr == NULL) {
+      p->b_next = NULL;
+      buf->bh_first = p;
+      buf->bh_curr = p;
+    } else {
+      p->b_next = buf->bh_curr->b_next;
+      buf->bh_curr->b_next = p;
+      buf->bh_curr = p;
+    }
   }
   return;
 }
@@ -356,17 +366,17 @@ static int read_readbuffers(int advance)
 static int read_readbuf(buffheader_T *buf, int advance)
 {
   char_u c;
-  buffblock_T *curr;
 
-  if (buf->bh_first.b_next == NULL) /* buffer is empty */
+  if (buf->bh_first == NULL) {  // buffer is empty
     return NUL;
+  }
 
-  curr = buf->bh_first.b_next;
+  buffblock_T *const curr = buf->bh_first;
   c = curr->b_str[buf->bh_index];
 
   if (advance) {
     if (curr->b_str[++buf->bh_index] == NUL) {
-      buf->bh_first.b_next = curr->b_next;
+      buf->bh_first = curr->b_next;
       xfree(curr);
       buf->bh_index = 0;
     }
@@ -379,12 +389,12 @@ static int read_readbuf(buffheader_T *buf, int advance)
  */
 static void start_stuff(void)
 {
-  if (readbuf1.bh_first.b_next != NULL) {
-    readbuf1.bh_curr = &(readbuf1.bh_first);
+  if (readbuf1.bh_first != NULL) {
+    readbuf1.bh_curr = readbuf1.bh_first;
     readbuf1.bh_space = 0;
   }
-  if (readbuf2.bh_first.b_next != NULL) {
-    readbuf2.bh_curr = &(readbuf2.bh_first);
+  if (readbuf2.bh_first != NULL) {
+    readbuf2.bh_curr = readbuf2.bh_first;
     readbuf2.bh_space = 0;
   }
 }
@@ -394,7 +404,8 @@ static void start_stuff(void)
  */
 int stuff_empty(void)
 {
-  return (readbuf1.bh_first.b_next == NULL && readbuf2.bh_first.b_next == NULL);
+  return (readbuf1.bh_first == NULL
+          && readbuf2.bh_first == NULL);
 }
 
 /*
@@ -403,7 +414,7 @@ int stuff_empty(void)
  */
 int readbuf1_empty(void)
 {
-  return (readbuf1.bh_first.b_next == NULL);
+  return (readbuf1.bh_first == NULL);
 }
 
 /*
@@ -461,7 +472,7 @@ void ResetRedobuff(void)
   if (!block_redo) {
     free_buff(&old_redobuff);
     old_redobuff = redobuff;
-    redobuff.bh_first.b_next = NULL;
+    redobuff.bh_first = NULL;
   }
 }
 
@@ -474,7 +485,7 @@ void CancelRedo(void)
   if (!block_redo) {
     free_buff(&redobuff);
     redobuff = old_redobuff;
-    old_redobuff.bh_first.b_next = NULL;
+    old_redobuff.bh_first = NULL;
     start_stuff();
     while (read_readbuffers(TRUE) != NUL) {
     }
@@ -486,9 +497,9 @@ void CancelRedo(void)
 void saveRedobuff(save_redo_T *save_redo)
 {
   save_redo->sr_redobuff = redobuff;
-  redobuff.bh_first.b_next = NULL;
+  redobuff.bh_first = NULL;
   save_redo->sr_old_redobuff = old_redobuff;
-  old_redobuff.bh_first.b_next = NULL;
+  old_redobuff.bh_first = NULL;
 
   // Make a copy, so that ":normal ." in a function works.
   char *const s = (char *)get_buffcont(&save_redo->sr_redobuff, false);
@@ -668,12 +679,10 @@ static int read_redo(bool init, bool old_redo)
   int i;
 
   if (init) {
-    if (old_redo)
-      bp = old_redobuff.bh_first.b_next;
-    else
-      bp = redobuff.bh_first.b_next;
-    if (bp == NULL)
+    bp = old_redo ? old_redobuff.bh_first : redobuff.bh_first;
+    if (bp == NULL) {
       return FAIL;
+    }
     p = bp->b_str;
     return OK;
   }
@@ -1206,9 +1215,9 @@ void save_typeahead(tasave_T *tp)
   old_char = -1;
 
   tp->save_readbuf1 = readbuf1;
-  readbuf1.bh_first.b_next = NULL;
+  readbuf1.bh_first = NULL;
   tp->save_readbuf2 = readbuf2;
-  readbuf2.bh_first.b_next = NULL;
+  readbuf2.bh_first = NULL;
 }
 
 /*