revert: "refactor: eliminate autocmd_fname_full global"

This reverts commit 82cd0be2ea.

src/nvim/autocmd.c

@@ -1603,6 +1603,7 @@ bool apply_autocmds_group(event_T event, char *fname, char *fname_io, bool force
 
   // Save the autocmd_* variables and info about the current buffer.
   char *save_autocmd_fname = autocmd_fname;
+  bool save_autocmd_fname_full = autocmd_fname_full;
   int save_autocmd_bufnr = autocmd_bufnr;
   char *save_autocmd_match = autocmd_match;
   int save_autocmd_busy = autocmd_busy;
@@ -1631,6 +1632,7 @@ bool apply_autocmds_group(event_T event, char *fname, char *fname_io, bool force
     // Allocate MAXPATHL for when eval_vars() resolves the fullpath.
     autocmd_fname = xstrnsave(autocmd_fname, MAXPATHL);
   }
+  autocmd_fname_full = false;  // call FullName_save() later
 
   // Set the buffer number to be used for <abuf>.
   autocmd_bufnr = buf == NULL ? 0 : buf->b_fnum;
@@ -1806,6 +1808,7 @@ bool apply_autocmds_group(event_T event, char *fname, char *fname_io, bool force
   estack_pop();
   xfree(autocmd_fname);
   autocmd_fname = save_autocmd_fname;
+  autocmd_fname_full = save_autocmd_fname_full;
   autocmd_bufnr = save_autocmd_bufnr;
   autocmd_match = save_autocmd_match;
   current_sctx = save_current_sctx;

src/nvim/eval.c

@@ -8609,6 +8609,7 @@ typval_T eval_call_provider(char *provider, char *method, list_T *arguments, boo
     .es_entry = ((estack_T *)exestack.ga_data)[exestack.ga_len - 1],
     .autocmd_fname = autocmd_fname,
     .autocmd_match = autocmd_match,
+    .autocmd_fname_full = autocmd_fname_full,
     .autocmd_bufnr = autocmd_bufnr,
     .funccalp = (void *)get_current_funccal()
   };

src/nvim/eval/funcs.c

@@ -6552,6 +6552,7 @@ static void f_rpcrequest(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
   sctx_T save_current_sctx;
   char *save_autocmd_fname, *save_autocmd_match;
+  bool save_autocmd_fname_full;
   int save_autocmd_bufnr;
   funccal_entry_T funccal_entry;
 
@@ -6561,6 +6562,7 @@ static void f_rpcrequest(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     save_current_sctx = current_sctx;
     save_autocmd_fname = autocmd_fname;
     save_autocmd_match = autocmd_match;
+    save_autocmd_fname_full = autocmd_fname_full;
     save_autocmd_bufnr = autocmd_bufnr;
     save_funccal(&funccal_entry);
 
@@ -6569,6 +6571,7 @@ static void f_rpcrequest(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     ((estack_T *)exestack.ga_data)[exestack.ga_len++] = provider_caller_scope.es_entry;
     autocmd_fname = provider_caller_scope.autocmd_fname;
     autocmd_match = provider_caller_scope.autocmd_match;
+    autocmd_fname_full = provider_caller_scope.autocmd_fname_full;
     autocmd_bufnr = provider_caller_scope.autocmd_bufnr;
     set_current_funccal((funccall_T *)(provider_caller_scope.funccalp));
   }
@@ -6586,6 +6589,7 @@ static void f_rpcrequest(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     exestack.ga_len--;
     autocmd_fname = save_autocmd_fname;
     autocmd_match = save_autocmd_match;
+    autocmd_fname_full = save_autocmd_fname_full;
     autocmd_bufnr = save_autocmd_bufnr;
     restore_funccal();
   }

src/nvim/ex_docmd.c

@@ -6899,12 +6899,10 @@ char *eval_vars(char *src, const char *srcstart, size_t *usedlen, linenr_T *lnum
       break;
 
     case SPEC_AFILE:  // file name for autocommand
-      if (autocmd_fname != NULL
+      if (autocmd_fname != NULL && !autocmd_fname_full) {
-          && !path_is_absolute(autocmd_fname)
-          // For CmdlineEnter and related events, <afile> is not a path! #9348
-          && !strequal("/", autocmd_fname)) {
         // Still need to turn the fname into a full path.  It was
         // postponed to avoid a delay when <afile> is not used.
+        autocmd_fname_full = true;
         result = FullName_save(autocmd_fname, false);
         // Copy into `autocmd_fname`, don't reassign it. #8165
         xstrlcpy(autocmd_fname, result, MAXPATHL);

src/nvim/globals.h

@@ -336,6 +336,7 @@ EXTERN struct caller_scope {
   sctx_T script_ctx;
   estack_T es_entry;
   char *autocmd_fname, *autocmd_match;
+  bool autocmd_fname_full;
   int autocmd_bufnr;
   void *funccalp;
 } provider_caller_scope;
@@ -759,6 +760,7 @@ EXTERN char *last_cmdline INIT(= NULL);        // last command line (for ":)
 EXTERN char *repeat_cmdline INIT(= NULL);      // command line for "."
 EXTERN char *new_last_cmdline INIT(= NULL);    // new value for last_cmdline
 EXTERN char *autocmd_fname INIT(= NULL);       // fname for <afile> on cmdline
+EXTERN bool autocmd_fname_full INIT(= false);  // autocmd_fname is full path
 EXTERN int autocmd_bufnr INIT(= 0);            // fnum for <abuf> on cmdline
 EXTERN char *autocmd_match INIT(= NULL);       // name for <amatch> on cmdline
 EXTERN bool did_cursorhold INIT(= false);      // set when CursorHold t'gerd