vim-patch:8.2.4475: fuzzy cmdline completion does not work for lower case

Problem:    Fuzzy cmdline completion does not work for lower case.
Solution:   Also use fuzzy completion for lower case input. (Yegappan
            Lakshmanan, closes vim/vim#9849)

https://github.com/vim/vim/commit/4df5b33f206210fec2a0297aea27e7db8b5173c0

Initialize "regmatch" to avoid using uninitialized memory.

Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>

2 files changed, 29 insertions, 9 deletions

diff --git a/src/nvim/cmdexpand.c b/src/nvim/cmdexpand.c
index 566a17b82b..b3f6047961 100644
--- a/src/nvim/cmdexpand.c
+++ b/src/nvim/cmdexpand.c
@@ -1373,6 +1373,7 @@ static const char *set_cmd_index(const char *cmd, exarg_T *eap, expand_T *xp, in
 {
   const char *p = NULL;
   size_t len = 0;
+  const bool fuzzy = cmdline_fuzzy_complete(cmd);
 
   // Isolate the command and search for it in the command table.
   // Exceptions:
@@ -1413,7 +1414,9 @@ static const char *set_cmd_index(const char *cmd, exarg_T *eap, expand_T *xp, in
 
     eap->cmdidx = excmd_get_cmdidx(cmd, len);
 
-    if (cmd[0] >= 'A' && cmd[0] <= 'Z') {
+    // User defined commands support alphanumeric characters.
+    // Also when doing fuzzy expansion, support alphanumeric characters.
+    if ((cmd[0] >= 'A' && cmd[0] <= 'Z') || (fuzzy && *p != NUL)) {
       while (ASCII_ISALNUM(*p) || *p == '*') {  // Allow * wild card
         p++;
       }
@@ -2630,9 +2633,10 @@ static int map_wildopts_to_ewflags(int options)
 /// @param options  WILD_ flags
 static int ExpandFromContext(expand_T *xp, char *pat, char ***matches, int *numMatches, int options)
 {
-  regmatch_T regmatch;
+  regmatch_T regmatch = { .rm_ic = false };
   int ret;
   int flags = map_wildopts_to_ewflags(options);
+  const bool fuzzy = cmdline_fuzzy_complete(pat);
 
   if (xp->xp_context == EXPAND_FILES
       || xp->xp_context == EXPAND_DIRECTORIES
@@ -2713,13 +2717,15 @@ static int ExpandFromContext(expand_T *xp, char *pat, char ***matches, int *numM
     return nlua_expand_pat(xp, pat, numMatches, matches);
   }
 
-  regmatch.regprog = vim_regcomp(pat, magic_isset() ? RE_MAGIC : 0);
-  if (regmatch.regprog == NULL) {
-    return FAIL;
-  }
+  if (!fuzzy) {
+    regmatch.regprog = vim_regcomp(pat, magic_isset() ? RE_MAGIC : 0);
+    if (regmatch.regprog == NULL) {
+      return FAIL;
+    }
 
-  // set ignore-case according to p_ic, p_scs and pat
-  regmatch.rm_ic = ignorecase(pat);
+    // set ignore-case according to p_ic, p_scs and pat
+    regmatch.rm_ic = ignorecase(pat);
+  }
 
   if (xp->xp_context == EXPAND_SETTINGS
       || xp->xp_context == EXPAND_BOOL_SETTINGS) {
@@ -2732,7 +2738,9 @@ static int ExpandFromContext(expand_T *xp, char *pat, char ***matches, int *numM
     ret = ExpandOther(pat, xp, &regmatch, matches, numMatches);
   }
 
-  vim_regfree(regmatch.regprog);
+  if (!fuzzy) {
+    vim_regfree(regmatch.regprog);
+  }
   xfree(tofree);
 
   return ret;
diff --git a/src/nvim/testdir/test_cmdline.vim b/src/nvim/testdir/test_cmdline.vim
index f5726c093b..16d99cf4c5 100644
--- a/src/nvim/testdir/test_cmdline.vim
+++ b/src/nvim/testdir/test_cmdline.vim
@@ -2989,6 +2989,18 @@ func Test_wildoptions_fuzzy()
   delcommand T123FendingOff
   %bw
 
+  " Test for fuzzy completion of a command with lower case letters and a
+  " number
+  command Foo2Bar :
+  set wildoptions=fuzzy
+  call feedkeys(":foo2\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"Foo2Bar', @:)
+  call feedkeys(":foo\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"Foo2Bar', @:)
+  call feedkeys(":bar\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"Foo2Bar', @:)
+  delcommand Foo2Bar
+
   set wildoptions&
   %bw!
 endfunc