vim-patch:8.2.2813: cannot grep using fuzzy matching

Problem:    Cannot grep using fuzzy matching.
Solution:   Add the "f" flag to :vimgrep. (Yegappan Lakshmanan, closes vim/vim#8152)
https://github.com/vim/vim/commit/bb01a1ef3a093cdb36877ba73474719c531dc8cb

7 files changed, 162 insertions, 70 deletions

diff --git a/runtime/doc/quickfix.txt b/runtime/doc/quickfix.txt
index bb4d807413..c7289cfca6 100644
--- a/runtime/doc/quickfix.txt
+++ b/runtime/doc/quickfix.txt
@@ -989,7 +989,7 @@ commands can be combined to create a NewGrep command: >
 5.1 using Vim's internal grep
 
 					*:vim* *:vimgrep* *E682* *E683*
-:vim[grep][!] /{pattern}/[g][j] {file} ...
+:vim[grep][!] /{pattern}/[g][j][f] {file} ...
 			Search for {pattern} in the files {file} ... and set
 			the error list to the matches.  Files matching
 			'wildignore' are ignored; files in 'suffixes' are
@@ -1042,20 +1042,20 @@ commands can be combined to create a NewGrep command: >
 				:vimgrep Error *.c
 <
 							*:lv* *:lvimgrep*
-:lv[imgrep][!] /{pattern}/[g][j] {file} ...
+:lv[imgrep][!] /{pattern}/[g][j][f] {file} ...
 :lv[imgrep][!] {pattern} {file} ...
 			Same as ":vimgrep", except the location list for the
 			current window is used instead of the quickfix list.
 
 						*:vimgrepa* *:vimgrepadd*
-:vimgrepa[dd][!] /{pattern}/[g][j] {file} ...
+:vimgrepa[dd][!] /{pattern}/[g][j][f] {file} ...
 :vimgrepa[dd][!] {pattern} {file} ...
 			Just like ":vimgrep", but instead of making a new list
 			of errors the matches are appended to the current
 			list.
 
 						*:lvimgrepa* *:lvimgrepadd*
-:lvimgrepa[dd][!] /{pattern}/[g][j] {file} ...
+:lvimgrepa[dd][!] /{pattern}/[g][j][f] {file} ...
 :lvimgrepa[dd][!] {pattern} {file} ...
 			Same as ":vimgrepadd", except the location list for
 			the current window is used instead of the quickfix
diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index 3b3d4e50cc..81fce3565a 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -6141,12 +6141,14 @@ char_u *skip_vimgrep_pat(char_u *p, char_u **s, int *flags)
     p++;
 
     // Find the flags
-    while (*p == 'g' || *p == 'j') {
+    while (*p == 'g' || *p == 'j' || *p == 'f') {
       if (flags != NULL) {
         if (*p == 'g') {
           *flags |= VGR_GLOBAL;
-        } else {
+        } else if (*p == 'j') {
           *flags |= VGR_NOJUMP;
+        } else {
+          *flags |= VGR_FUZZY;
         }
       }
       p++;
diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index 0196e05455..c609daa55c 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -5194,49 +5194,93 @@ static bool vgr_qflist_valid(win_T *wp, qf_info_T *qi, unsigned qfid, char_u *ti
 
 /// Search for a pattern in all the lines in a buffer and add the matching lines
 /// to a quickfix list.
-static bool vgr_match_buflines(qf_list_T *qfl, char_u *fname, buf_T *buf, regmmatch_T *regmatch,
-                               long *tomatch, int duplicate_name, int flags)
-  FUNC_ATTR_NONNULL_ARG(1, 3, 4, 5)
+static bool vgr_match_buflines(qf_list_T *qfl, char_u *fname, buf_T *buf, char_u *spat,
+                               regmmatch_T *regmatch, long *tomatch, int duplicate_name, int flags)
+  FUNC_ATTR_NONNULL_ARG(1, 3, 4, 5, 6)
 {
   bool found_match = false;
 
   for (long lnum = 1; lnum <= buf->b_ml.ml_line_count && *tomatch > 0; lnum++) {
     colnr_T col = 0;
-    while (vim_regexec_multi(regmatch, curwin, buf, lnum, col, NULL,
-                             NULL) > 0) {
-      // Pass the buffer number so that it gets used even for a
-      // dummy buffer, unless duplicate_name is set, then the
-      // buffer will be wiped out below.
-      if (qf_add_entry(qfl,
-                       NULL,  // dir
-                       fname,
-                       NULL,
-                       duplicate_name ? 0 : buf->b_fnum,
-                       ml_get_buf(buf, regmatch->startpos[0].lnum + lnum,
-                                  false),
-                       regmatch->startpos[0].lnum + lnum,
-                       regmatch->endpos[0].lnum + lnum,
-                       regmatch->startpos[0].col + 1,
-                       regmatch->endpos[0].col + 1,
-                       false,  // vis_col
-                       NULL,   // search pattern
-                       0,      // nr
-                       0,      // type
-                       true)    // valid
-          == QF_FAIL) {
-        got_int = true;
-        break;
-      }
-      found_match = true;
-      if (--*tomatch == 0) {
-        break;
-      }
-      if ((flags & VGR_GLOBAL) == 0 || regmatch->endpos[0].lnum > 0) {
-        break;
+    if (!(flags & VGR_FUZZY)) {
+      // Regular expression match
+      while (vim_regexec_multi(regmatch, curwin, buf, lnum, col, NULL, NULL) > 0) {
+        // Pass the buffer number so that it gets used even for a
+        // dummy buffer, unless duplicate_name is set, then the
+        // buffer will be wiped out below.
+        if (qf_add_entry(qfl,
+                         NULL,   // dir
+                         fname,
+                         NULL,
+                         duplicate_name ? 0 : buf->b_fnum,
+                         ml_get_buf(buf, regmatch->startpos[0].lnum + lnum, false),
+                         regmatch->startpos[0].lnum + lnum,
+                         regmatch->endpos[0].lnum + lnum,
+                         regmatch->startpos[0].col + 1,
+                         regmatch->endpos[0].col + 1,
+                         false,  // vis_col
+                         NULL,   // search pattern
+                         0,      // nr
+                         0,      // type
+                         true)   // valid
+            == QF_FAIL) {
+          got_int = true;
+          break;
+        }
+        found_match = true;
+        if (--*tomatch == 0) {
+          break;
+        }
+        if ((flags & VGR_GLOBAL) == 0 || regmatch->endpos[0].lnum > 0) {
+          break;
+        }
+        col = regmatch->endpos[0].col + (col == regmatch->endpos[0].col);
+        if (col > (colnr_T)STRLEN(ml_get_buf(buf, lnum, false))) {
+          break;
+        }
       }
-      col = regmatch->endpos[0].col + (col == regmatch->endpos[0].col);
-      if (col > (colnr_T)STRLEN(ml_get_buf(buf, lnum, false))) {
-        break;
+    } else {
+      const size_t pat_len = STRLEN(spat);
+      char_u *const str = ml_get_buf(buf, lnum, false);
+      int score;
+      uint32_t matches[MAX_FUZZY_MATCHES];
+      const size_t sz = sizeof(matches) / sizeof(matches[0]);
+
+      // Fuzzy string match
+      while (fuzzy_match(str + col, spat, false, &score, matches, (int)sz) > 0) {
+        // Pass the buffer number so that it gets used even for a
+        // dummy buffer, unless duplicate_name is set, then the
+        // buffer will be wiped out below.
+        if (qf_add_entry(qfl,
+                         NULL,   // dir
+                         fname,
+                         NULL,
+                         duplicate_name ? 0 : buf->b_fnum,
+                         str,
+                         lnum,
+                         0,
+                         (colnr_T)matches[0] + col + 1,
+                         0,
+                         false,  // vis_col
+                         NULL,   // search pattern
+                         0,      // nr
+                         0,      // type
+                         true)   // valid
+            == QF_FAIL) {
+          got_int = true;
+          break;
+        }
+        found_match = true;
+        if (--*tomatch == 0) {
+          break;
+        }
+        if ((flags & VGR_GLOBAL) == 0) {
+          break;
+        }
+        col = (colnr_T)matches[pat_len - 1] + col + 1;
+        if (col > (colnr_T)STRLEN(str)) {
+          break;
+        }
       }
     }
     line_breakcheck();
@@ -5418,8 +5462,7 @@ void ex_vimgrep(exarg_T *eap)
     } else {
       // Try for a match in all lines of the buffer.
       // For ":1vimgrep" look for first match only.
-      found_match = vgr_match_buflines(qf_get_curlist(qi),
-                                       fname, buf, &regmatch, &tomatch,
+      found_match = vgr_match_buflines(qf_get_curlist(qi), fname, buf, s, &regmatch, &tomatch,
                                        duplicate_name, flags);
 
       if (using_dummy) {
diff --git a/src/nvim/quickfix.h b/src/nvim/quickfix.h
index f5178e332a..0da43e436c 100644
--- a/src/nvim/quickfix.h
+++ b/src/nvim/quickfix.h
@@ -7,6 +7,7 @@
 // flags for skip_vimgrep_pat()
 #define VGR_GLOBAL      1
 #define VGR_NOJUMP      2
+#define VGR_FUZZY       4
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "quickfix.h.generated.h"
diff --git a/src/nvim/search.c b/src/nvim/search.c
index 960c0e97c0..3a2435e07a 100644
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -48,8 +48,6 @@
 #include "nvim/vim.h"
 #include "nvim/window.h"
 
-typedef uint32_t matchidx_T;
-
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "search.c.generated.h"
 #endif
@@ -4843,13 +4841,11 @@ typedef struct {
 #define SCORE_NONE -9999
 
 #define FUZZY_MATCH_RECURSION_LIMIT 10
-/// Maximum number of characters that can be fuzzy matched
-#define MAXMATCHES 256
 
 /// Compute a score for a fuzzy matched string. The matching character locations
 /// are in 'matches'.
 static int fuzzy_match_compute_score(const char_u *const str, const int strSz,
-                                     const matchidx_T *const matches, const int numMatches)
+                                     const uint32_t *const matches, const int numMatches)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_PURE
 {
   // Initialize score
@@ -4868,10 +4864,10 @@ static int fuzzy_match_compute_score(const char_u *const str, const int strSz,
 
   // Apply ordering bonuses
   for (int i = 0; i < numMatches; i++) {
-    const matchidx_T currIdx = matches[i];
+    const uint32_t currIdx = matches[i];
 
     if (i > 0) {
-      const matchidx_T prevIdx = matches[i - 1];
+      const uint32_t prevIdx = matches[i - 1];
 
       // Sequential
       if (currIdx == prevIdx + 1) {
@@ -4887,7 +4883,7 @@ static int fuzzy_match_compute_score(const char_u *const str, const int strSz,
       const char_u *p = str;
       int neighbor;
 
-      for (matchidx_T sidx = 0; sidx < currIdx; sidx++) {
+      for (uint32_t sidx = 0; sidx < currIdx; sidx++) {
         neighbor = utf_ptr2char(p);
         MB_PTR_ADV(p);
       }
@@ -4913,16 +4909,16 @@ static int fuzzy_match_compute_score(const char_u *const str, const int strSz,
 
 /// Perform a recursive search for fuzzy matching 'fuzpat' in 'str'.
 /// @return the number of matching characters.
-static int fuzzy_match_recursive(const char_u *fuzpat, const char_u *str, matchidx_T strIdx,
+static int fuzzy_match_recursive(const char_u *fuzpat, const char_u *str, uint32_t strIdx,
                                  int *const outScore, const char_u *const strBegin,
-                                 const int strLen, const matchidx_T *const srcMatches,
-                                 matchidx_T *const matches, const int maxMatches, int nextMatch,
+                                 const int strLen, const uint32_t *const srcMatches,
+                                 uint32_t *const matches, const int maxMatches, int nextMatch,
                                  int *const recursionCount)
   FUNC_ATTR_NONNULL_ARG(1, 2, 4, 5, 8, 11) FUNC_ATTR_WARN_UNUSED_RESULT
 {
   // Recursion params
   bool recursiveMatch = false;
-  matchidx_T bestRecursiveMatches[MAXMATCHES];
+  uint32_t bestRecursiveMatches[MAX_FUZZY_MATCHES];
   int bestRecursiveScore = 0;
 
   // Count recursions
@@ -4932,7 +4928,7 @@ static int fuzzy_match_recursive(const char_u *fuzpat, const char_u *str, matchi
   }
 
   // Detect end of strings
-  if (*fuzpat == '\0' || *str == '\0') {
+  if (*fuzpat == NUL || *str == NUL) {
     return 0;
   }
 
@@ -4956,7 +4952,7 @@ static int fuzzy_match_recursive(const char_u *fuzpat, const char_u *str, matchi
       }
 
       // Recursive call that "skips" this match
-      matchidx_T recursiveMatches[MAXMATCHES];
+      uint32_t recursiveMatches[MAX_FUZZY_MATCHES];
       int recursiveScore = 0;
       const char_u *const next_char = str + utfc_ptr2len(str);
       if (fuzzy_match_recursive(fuzpat, next_char, strIdx + 1, &recursiveScore, strBegin, strLen,
@@ -4965,7 +4961,8 @@ static int fuzzy_match_recursive(const char_u *fuzpat, const char_u *str, matchi
                                 recursionCount)) {
         // Pick best recursive score
         if (!recursiveMatch || recursiveScore > bestRecursiveScore) {
-          memcpy(bestRecursiveMatches, recursiveMatches, MAXMATCHES * sizeof(recursiveMatches[0]));
+          memcpy(bestRecursiveMatches, recursiveMatches,
+                 MAX_FUZZY_MATCHES * sizeof(recursiveMatches[0]));
           bestRecursiveScore = recursiveScore;
         }
         recursiveMatch = true;
@@ -5008,13 +5005,13 @@ static int fuzzy_match_recursive(const char_u *fuzpat, const char_u *str, matchi
 /// normalized and varies with pattern.
 /// Recursion is limited internally (default=10) to prevent degenerate cases
 /// (pat_arg="aaaaaa" str="aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa").
-/// Uses char_u for match indices. Therefore patterns are limited to MAXMATCHES
-/// characters.
+/// Uses char_u for match indices. Therefore patterns are limited to
+/// MAX_FUZZY_MATCHES characters.
 ///
 /// @return true if 'pat_arg' matches 'str'. Also returns the match score in
 /// 'outScore' and the matching character positions in 'matches'.
-static bool fuzzy_match(char_u *const str, const char_u *const pat_arg, const bool matchseq,
-                        int *const outScore, matchidx_T *const matches, const int maxMatches)
+bool fuzzy_match(char_u *const str, const char_u *const pat_arg, const bool matchseq,
+                 int *const outScore, uint32_t *const matches, const int maxMatches)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT
 {
   const int len = mb_charlen(str);
@@ -5108,7 +5105,7 @@ static void fuzzy_match_in_list(list_T *const items, char_u *const str, const bo
   fuzzyItem_T *const ptrs = xcalloc(len, sizeof(fuzzyItem_T));
   long i = 0;
   bool found_match = false;
-  matchidx_T matches[MAXMATCHES];
+  uint32_t matches[MAX_FUZZY_MATCHES];
 
   // For all the string items in items, get the fuzzy matching score
   TV_LIST_ITER(items, li, {
@@ -5250,8 +5247,8 @@ static void do_fuzzymatch(const typval_T *const argvars, typval_T *const rettv,
     // To search a dict, either a callback function or a key can be
     // specified.
     dict_T *const d = argvars[2].vval.v_dict;
-    const dictitem_T *di;
-    if ((di = tv_dict_find(d, "key", -1)) != NULL) {
+    const dictitem_T *const di = tv_dict_find(d, "key", -1);
+    if (di != NULL) {
       if (di->di_tv.v_type != VAR_STRING || di->di_tv.vval.v_string == NULL
           || *di->di_tv.vval.v_string == NUL) {
         semsg(_(e_invarg2), tv_get_string(&di->di_tv));
@@ -5262,7 +5259,7 @@ static void do_fuzzymatch(const typval_T *const argvars, typval_T *const rettv,
       semsg(_(e_invargval), "text_cb");
       return;
     }
-    if ((di = tv_dict_find(d, "matchseq", -1)) != NULL) {
+    if (tv_dict_find(d, "matchseq", -1) != NULL) {
       matchseq = true;
     }
   }
diff --git a/src/nvim/search.h b/src/nvim/search.h
index 15b8d41f39..53059cc1ea 100644
--- a/src/nvim/search.h
+++ b/src/nvim/search.h
@@ -55,6 +55,9 @@
 #define SEARCH_STAT_DEF_MAX_COUNT 99
 #define SEARCH_STAT_BUF_LEN 12
 
+/// Maximum number of characters that can be fuzzy matched
+#define MAX_FUZZY_MATCHES 256
+
 /// Structure containing offset definition for the last search pattern
 ///
 /// @note Only offset for the last search pattern is used, not for the last
diff --git a/src/nvim/testdir/test_quickfix.vim b/src/nvim/testdir/test_quickfix.vim
index f137ed5346..00679e1958 100644
--- a/src/nvim/testdir/test_quickfix.vim
+++ b/src/nvim/testdir/test_quickfix.vim
@@ -32,7 +32,7 @@ func s:setup_commands(cchar)
     command! -count -nargs=* -bang Xnfile <mods><count>cnfile<bang> <args>
     command! -nargs=* -bang Xpfile <mods>cpfile<bang> <args>
     command! -nargs=* Xexpr <mods>cexpr <args>
-    command! -count -nargs=* Xvimgrep <mods> <count>vimgrep <args>
+    command! -count=999 -nargs=* Xvimgrep <mods> <count>vimgrep <args>
     command! -nargs=* Xvimgrepadd <mods> vimgrepadd <args>
     command! -nargs=* Xgrep <mods> grep <args>
     command! -nargs=* Xgrepadd <mods> grepadd <args>
@@ -69,7 +69,7 @@ func s:setup_commands(cchar)
     command! -count -nargs=* -bang Xnfile <mods><count>lnfile<bang> <args>
     command! -nargs=* -bang Xpfile <mods>lpfile<bang> <args>
     command! -nargs=* Xexpr <mods>lexpr <args>
-    command! -count -nargs=* Xvimgrep <mods> <count>lvimgrep <args>
+    command! -count=999 -nargs=* Xvimgrep <mods> <count>lvimgrep <args>
     command! -nargs=* Xvimgrepadd <mods> lvimgrepadd <args>
     command! -nargs=* Xgrep <mods> lgrep <args>
     command! -nargs=* Xgrepadd <mods> lgrepadd <args>
@@ -5028,6 +5028,52 @@ func Test_qfbuf_update()
   call Xqfbuf_update('l')
 endfunc
 
+" Test for the :vimgrep 'f' flag (fuzzy match)
+func Xvimgrep_fuzzy_match(cchar)
+  call s:setup_commands(a:cchar)
+
+  Xvimgrep /three one/f Xfile*
+  let l = g:Xgetlist()
+  call assert_equal(2, len(l))
+  call assert_equal(['Xfile1', 1, 9, 'one two three'],
+        \ [bufname(l[0].bufnr), l[0].lnum, l[0].col, l[0].text])
+  call assert_equal(['Xfile2', 2, 1, 'three one two'],
+        \ [bufname(l[1].bufnr), l[1].lnum, l[1].col, l[1].text])
+
+  Xvimgrep /the/f Xfile*
+  let l = g:Xgetlist()
+  call assert_equal(3, len(l))
+  call assert_equal(['Xfile1', 1, 9, 'one two three'],
+        \ [bufname(l[0].bufnr), l[0].lnum, l[0].col, l[0].text])
+  call assert_equal(['Xfile2', 2, 1, 'three one two'],
+        \ [bufname(l[1].bufnr), l[1].lnum, l[1].col, l[1].text])
+  call assert_equal(['Xfile2', 4, 4, 'aaathreeaaa'],
+        \ [bufname(l[2].bufnr), l[2].lnum, l[2].col, l[2].text])
+
+  Xvimgrep /aaa/fg Xfile*
+  let l = g:Xgetlist()
+  call assert_equal(4, len(l))
+  call assert_equal(['Xfile1', 2, 1, 'aaaaaa'],
+        \ [bufname(l[0].bufnr), l[0].lnum, l[0].col, l[0].text])
+  call assert_equal(['Xfile1', 2, 4, 'aaaaaa'],
+        \ [bufname(l[1].bufnr), l[1].lnum, l[1].col, l[1].text])
+  call assert_equal(['Xfile2', 4, 1, 'aaathreeaaa'],
+        \ [bufname(l[2].bufnr), l[2].lnum, l[2].col, l[2].text])
+  call assert_equal(['Xfile2', 4, 9, 'aaathreeaaa'],
+        \ [bufname(l[3].bufnr), l[3].lnum, l[3].col, l[3].text])
+
+  call assert_fails('Xvimgrep /xyz/fg Xfile*', 'E480:')
+endfunc
+
+func Test_vimgrep_fuzzy_match()
+  call writefile(['one two three', 'aaaaaa'], 'Xfile1')
+  call writefile(['one', 'three one two', 'two', 'aaathreeaaa'], 'Xfile2')
+  call Xvimgrep_fuzzy_match('c')
+  call Xvimgrep_fuzzy_match('l')
+  call delete('Xfile1')
+  call delete('Xfile2')
+endfunc
+
 " Test for getting a specific item from a quickfix list
 func Xtest_getqflist_by_idx(cchar)
   call s:setup_commands(a:cchar)