vim-patch:8.2.3938: line comment start is also found in a string

Problem:    Line comment start is also found in a string.
Solution:   Skip line comments in a string.
ba26367fea

src/nvim/indent_c.c

@@ -41,9 +41,7 @@ static pos_T *ind_find_start_comment(void)  // XXX
 
 pos_T *find_start_comment(int ind_maxcomment)  // XXX
 {
-  pos_T       *pos;
-  char_u      *line;
-  char_u      *p;
+  pos_T *pos;
   int64_t cur_maxcomment = ind_maxcomment;
 
   for (;; ) {
@@ -55,11 +53,9 @@ pos_T *find_start_comment(int ind_maxcomment)  // XXX
      * Check if the comment start we found is inside a string.
      * If it is then restrict the search to below this line and try again.
      */
-    line = ml_get(pos->lnum);
-    for (p = line; *p && (colnr_T)(p - line) < pos->col; ++p)
-      p = skip_string(p);
-    if ((colnr_T)(p - line) <= pos->col)
+    if (!is_pos_in_string(ml_get(pos->lnum), pos->col)) {
       break;
+    }
     cur_maxcomment = curwin->w_cursor.lnum - pos->lnum - 1;
     if (cur_maxcomment <= 0) {
       pos = NULL;
@@ -110,8 +106,6 @@ static pos_T *ind_find_start_CORS(linenr_T *is_raw)
 static pos_T *find_start_rawstring(int ind_maxcomment)  // XXX
 {
     pos_T *pos;
-    char_u *line;
-    char_u *p;
     long cur_maxcomment = ind_maxcomment;
 
     for (;;)
@@ -124,11 +118,9 @@ static pos_T *find_start_rawstring(int ind_maxcomment)  // XXX
          * Check if the raw string start we found is inside a string.
          * If it is then restrict the search to below this line and try again.
          */
-        line = ml_get(pos->lnum);
-        for (p = line; *p && (colnr_T)(p - line) < pos->col; ++p)
-            p = skip_string(p);
-        if ((colnr_T)(p - line) <= pos->col)
-            break;
+        if (!is_pos_in_string(ml_get(pos->lnum), pos->col)) {
+          break;
+        }
         cur_maxcomment = curwin->w_cursor.lnum - pos->lnum - 1;
         if (cur_maxcomment <= 0)
         {
@@ -205,6 +197,16 @@ static char_u *skip_string(char_u *p)
   return p;
 }
 
+/// @returns true if "line[col]" is inside a C string.
+int is_pos_in_string(char_u *line, colnr_T col)
+{
+  char_u *p;
+
+  for (p = line; *p && (colnr_T)(p - line) < col; p++) {
+    p = skip_string(p);
+  }
+  return !((colnr_T)(p - line) <= col);
+}
 
 /*
  * Functions for C-indenting.

src/nvim/search.c

@@ -26,6 +26,7 @@
 #include "nvim/func_attr.h"
 #include "nvim/getchar.h"
 #include "nvim/indent.h"
+#include "nvim/indent_c.h"
 #include "nvim/main.h"
 #include "nvim/mark.h"
 #include "nvim/mbyte.h"
@@ -2313,11 +2314,8 @@ pos_T *findmatchlimit(oparg_T *oap, int initc, int flags, int64_t maxtravel)
   return (pos_T *)NULL;         // never found it
 }
 
-/*
- * Check if line[] contains a / / comment.
- * Return MAXCOL if not, otherwise return the column.
- * TODO: skip strings.
- */
+/// Check if line[] contains a / / comment.
+/// @returns MAXCOL if not, otherwise return the column.
 int check_linecomment(const char_u *line)
 {
   const char_u *p = line;  // scan from start
@@ -2338,7 +2336,8 @@ int check_linecomment(const char_u *line)
             in_str = true;
           }
         } else if (!in_str && ((p - line) < 2
-                               || (*(p - 1) != '\\' && *(p - 2) != '#'))) {
+                               || (*(p - 1) != '\\' && *(p - 2) != '#'))
+                   && !is_pos_in_string(line, (colnr_T)(p - line))) {
           break;                // found!
         }
         p++;
@@ -2348,9 +2347,11 @@ int check_linecomment(const char_u *line)
     }
   } else {
     while ((p = vim_strchr(p, '/')) != NULL) {
-      // accept a double /, unless it's preceded with * and followed by *,
-      // because * / / * is an end and start of a C comment
-      if (p[1] == '/' && (p == line || p[-1] != '*' || p[2] != '*')) {
+      // Accept a double /, unless it's preceded with * and followed by *,
+      // because * / / * is an end and start of a C comment.
+      // Only accept the position if it is not inside a string.
+      if (p[1] == '/' && (p == line || p[-1] != '*' || p[2] != '*')
+          && !is_pos_in_string(line, (colnr_T)(p - line))) {
         break;
       }
       ++p;

src/nvim/testdir/test_textformat.vim

@@ -261,6 +261,21 @@ func Test_format_c_comment()
   END
   call assert_equal(expected, getline(1, '$'))
 
+  " Using "o" does not repeat a comment in a string
+  %del
+  let text =<< trim END
+      nop;
+      val = " // This is not a comment";
+  END
+  call setline(1, text)
+  normal 2Gox
+  let expected =<< trim END
+      nop;
+      val = " // This is not a comment";
+      x
+  END
+  call assert_equal(expected, getline(1, '$'))
+
   " Using CTRL-U after "o" fixes the indent
   %del
   let text =<< trim END