vim-patch:9.1.0963: fuzzy-matching does not prefer full match (#31741)

Problem:  fuzzy-matching does not prefer full match
          (Maxim Kim)
Solution: add additional score for a full match
          (glepnir)

fixes: vim/vim#15654
closes: vim/vim#16300

https://github.com/vim/vim/commit/5a04999a7402201cf1b47ff10bc474dd1cdc24f4

3 files changed, 14 insertions, 2 deletions

diff --git a/runtime/doc/pattern.txt b/runtime/doc/pattern.txt
index 7f0938be05..be913e941e 100644
--- a/runtime/doc/pattern.txt
+++ b/runtime/doc/pattern.txt
@@ -1485,6 +1485,7 @@ criteria:
     - Matches at a camel case character (e.g. Case in CamelCase)
     - Matches after a path separator or a hyphen.
     - The number of unmatched characters in a string.
+    - A full/exact match is preferred.
 The matching string with the highest score is returned first.
 
 For example, when you search for the "get pat" string using fuzzy matching, it
diff --git a/src/nvim/search.c b/src/nvim/search.c
index faa14dfaf4..5a53122739 100644
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -2995,6 +2995,7 @@ static int fuzzy_match_compute_score(const char *const str, const int strSz,
   assert(numMatches > 0);  // suppress clang "result of operation is garbage"
   // Initialize score
   int score = 100;
+  bool is_exact_match = true;
 
   // Apply leading letter penalty
   int penalty = LEADING_LETTER_PENALTY * (int)matches[0];
@@ -3048,6 +3049,14 @@ static int fuzzy_match_compute_score(const char *const str, const int strSz,
       // First letter
       score += FIRST_LETTER_BONUS;
     }
+    // Check exact match condition
+    if (currIdx != (uint32_t)i) {
+      is_exact_match = false;
+    }
+  }
+  // Boost score for exact matches
+  if (is_exact_match && numMatches == strSz) {
+    score += 100;
   }
   return score;
 }
diff --git a/test/old/testdir/test_matchfuzzy.vim b/test/old/testdir/test_matchfuzzy.vim
index 90f3366b23..c2dc07ed10 100644
--- a/test/old/testdir/test_matchfuzzy.vim
+++ b/test/old/testdir/test_matchfuzzy.vim
@@ -23,6 +23,8 @@ func Test_matchfuzzy()
   call assert_equal(['aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'], matchfuzzy(['aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'], 'aa'))
   call assert_equal(256, matchfuzzy([repeat('a', 256)], repeat('a', 256))[0]->len())
   call assert_equal([], matchfuzzy([repeat('a', 300)], repeat('a', 257)))
+  " full match has highest score
+  call assert_equal(['Cursor', 'lCursor'], matchfuzzy(["hello", "lCursor", "Cursor"], "Cursor"))
   " matches with same score should not be reordered
   let l = ['abc1', 'abc2', 'abc3']
   call assert_equal(l, l->matchfuzzy('abc'))
@@ -101,7 +103,7 @@ func Test_matchfuzzypos()
   call assert_equal([['curl', 'world'], [[2,3], [2,3]], [128, 127]], matchfuzzypos(['world', 'curl'], 'rl'))
   call assert_equal([['curl', 'world'], [[2,3], [2,3]], [128, 127]], matchfuzzypos(['world', 'one', 'curl'], 'rl'))
   call assert_equal([['hello', 'hello world hello world'],
-        \ [[0, 1, 2, 3, 4], [0, 1, 2, 3, 4]], [275, 257]],
+        \ [[0, 1, 2, 3, 4], [0, 1, 2, 3, 4]], [375, 257]],
         \ matchfuzzypos(['hello world hello world', 'hello', 'world'], 'hello'))
   call assert_equal([['aaaaaaa'], [[0, 1, 2]], [191]], matchfuzzypos(['aaaaaaa'], 'aaa'))
   call assert_equal([['a  b'], [[0, 3]], [219]], matchfuzzypos(['a  b'], 'a  b'))
@@ -136,7 +138,7 @@ func Test_matchfuzzypos()
   call assert_equal([['foo bar baz'], [[0, 1, 2, 3, 4, 5, 10]], [326]], ['foo bar baz', 'foo', 'foo bar', 'baz bar']->matchfuzzypos('foo baz', {'matchseq': 1}))
   call assert_equal([[], [], []], ['foo bar baz', 'foo', 'foo bar', 'baz bar']->matchfuzzypos('one two'))
   call assert_equal([[], [], []], ['foo bar']->matchfuzzypos(" \t "))
-  call assert_equal([['grace'], [[1, 2, 3, 4, 2, 3, 4, 0, 1, 2, 3, 4]], [657]], ['grace']->matchfuzzypos('race ace grace'))
+  call assert_equal([['grace'], [[1, 2, 3, 4, 2, 3, 4, 0, 1, 2, 3, 4]], [757]], ['grace']->matchfuzzypos('race ace grace'))
 
   let l = [{'id' : 5, 'val' : 'crayon'}, {'id' : 6, 'val' : 'camera'}]
   call assert_equal([[{'id' : 6, 'val' : 'camera'}], [[0, 1, 2]], [192]],