From 0c27c1175b0ab168778fe0dfdff441885486dda3 Mon Sep 17 00:00:00 2001
From: yilisharcs <yilisharcs@gmail.com>
Date: Wed, 17 Dec 2025 13:05:16 -0300
Subject: [PATCH] refactor(editor): extract backup name generation logic #37001

Problem: The logic for generating backup file names is duplicated in
`buf_write_make_backup` and difficult to reuse.

Solution: Extract name generation logic into `buf_get_backup_name`.
---
 src/nvim/bufwrite.c | 107 ++++++++++++++++----------------------------
 1 file changed, 38 insertions(+), 69 deletions(-)

diff --git a/src/nvim/bufwrite.c b/src/nvim/bufwrite.c
index 1200660722..f6c6139372 100644
--- a/src/nvim/bufwrite.c
+++ b/src/nvim/bufwrite.c
@@ -715,6 +715,40 @@ static int get_fileinfo(buf_T *buf, char *fname, bool overwriting, bool forceit,
   return OK;
 }
 
+/// @return The backup file name
+char *buf_get_backup_name(char *fname, char **dirp, bool no_prepend_dot, char *backup_ext)
+{
+  char *backup = NULL;
+  // Isolate one directory name, using an entry in 'bdir'.
+  size_t dir_len = copy_option_part(dirp, IObuff, IOSIZE, ",");
+  char *p = IObuff + dir_len;
+  if (**dirp == NUL && !os_isdir(IObuff)) {
+    int ret;
+    char *failed_dir;
+    if ((ret = os_mkdir_recurse(IObuff, 0755, &failed_dir, NULL)) != 0) {
+      semsg(_("E303: Unable to create directory \"%s\" for backup file: %s"),
+            failed_dir, os_strerror(ret));
+      xfree(failed_dir);
+    }
+  }
+  if (after_pathsep(IObuff, p) && p[-1] == p[-2]) {
+    // path ends with '//', use full path
+    if ((p = make_percent_swname(IObuff, p, fname))
+        != NULL) {
+      backup = modname(p, backup_ext, no_prepend_dot);
+      xfree(p);
+    }
+  }
+  if (backup == NULL) {
+    char *rootname = get_file_in_dir(fname, IObuff);
+    if (rootname != NULL) {
+      backup = modname(rootname, backup_ext, no_prepend_dot);
+      xfree(rootname);
+    }
+  }
+  return backup;
+}
+
 static int buf_write_make_backup(char *fname, bool append, FileInfo *file_info_old, vim_acl_T acl,
                                  int perm, unsigned bkc, bool file_readonly, bool forceit,
                                  bool *backup_copyp, char **backupp, Error_T *err)
@@ -810,48 +844,14 @@ static int buf_write_make_backup(char *fname, bool append, FileInfo *file_info_o
     // and reused. Creation of a backup COPY will be attempted.
     char *dirp = p_bdir;
     while (*dirp) {
-      // Isolate one directory name, using an entry in 'bdir'.
-      size_t dir_len = copy_option_part(&dirp, IObuff, IOSIZE, ",");
-      char *p = IObuff + dir_len;
-      if (*dirp == NUL && !os_isdir(IObuff)) {
-        int ret;
-        char *failed_dir;
-        if ((ret = os_mkdir_recurse(IObuff, 0755, &failed_dir, NULL)) != 0) {
-          semsg(_("E303: Unable to create directory \"%s\" for backup file: %s"),
-                failed_dir, os_strerror(ret));
-          xfree(failed_dir);
-        }
-      }
-      if (after_pathsep(IObuff, p) && p[-1] == p[-2]) {
-        // Ends with '//', Use Full path
-        if ((p = make_percent_swname(IObuff, p, fname))
-            != NULL) {
-          *backupp = modname(p, backup_ext, no_prepend_dot);
-          xfree(p);
-        }
-      }
-
-      char *rootname = get_file_in_dir(fname, IObuff);
-      if (rootname == NULL) {
+      *backupp = buf_get_backup_name(fname, &dirp, no_prepend_dot, backup_ext);
+      if (*backupp == NULL) {
         some_error = true;                // out of memory
         goto nobackup;
       }
 
       FileInfo file_info_new;
       {
-        //
-        // Make the backup file name.
-        //
-        if (*backupp == NULL) {
-          *backupp = modname(rootname, backup_ext, no_prepend_dot);
-        }
-
-        if (*backupp == NULL) {
-          xfree(rootname);
-          some_error = true;                          // out of memory
-          goto nobackup;
-        }
-
         // Check if backup file already exists.
         if (os_fileinfo(*backupp, &file_info_new)) {
           if (os_fileinfo_id_equal(&file_info_new, file_info_old)) {
@@ -880,7 +880,6 @@ static int buf_write_make_backup(char *fname, bool append, FileInfo *file_info_o
           }
         }
       }
-      xfree(rootname);
 
       // Try to create the backup file
       if (*backupp != NULL) {
@@ -946,43 +945,13 @@ nobackup:
     // that works is used.
     char *dirp = p_bdir;
     while (*dirp) {
-      // Isolate one directory name and make the backup file name.
-      size_t dir_len = copy_option_part(&dirp, IObuff, IOSIZE, ",");
-      char *p = IObuff + dir_len;
-      if (*dirp == NUL && !os_isdir(IObuff)) {
-        int ret;
-        char *failed_dir;
-        if ((ret = os_mkdir_recurse(IObuff, 0755, &failed_dir, NULL)) != 0) {
-          semsg(_("E303: Unable to create directory \"%s\" for backup file: %s"),
-                failed_dir, os_strerror(ret));
-          xfree(failed_dir);
-        }
-      }
-      if (after_pathsep(IObuff, p) && p[-1] == p[-2]) {
-        // path ends with '//', use full path
-        if ((p = make_percent_swname(IObuff, p, fname))
-            != NULL) {
-          *backupp = modname(p, backup_ext, no_prepend_dot);
-          xfree(p);
-        }
-      }
-
-      if (*backupp == NULL) {
-        char *rootname = get_file_in_dir(fname, IObuff);
-        if (rootname == NULL) {
-          *backupp = NULL;
-        } else {
-          *backupp = modname(rootname, backup_ext, no_prepend_dot);
-          xfree(rootname);
-        }
-      }
-
+      *backupp = buf_get_backup_name(fname, &dirp, no_prepend_dot, backup_ext);
       if (*backupp != NULL) {
         // If we are not going to keep the backup file, don't
         // delete an existing one, try to use another name.
         // Change one character, just before the extension.
         if (!p_bk && os_path_exists(*backupp)) {
-          p = *backupp + strlen(*backupp) - 1 - strlen(backup_ext);
+          char *p = *backupp + strlen(*backupp) - 1 - strlen(backup_ext);
           p = MAX(p, *backupp);  // empty file name ???
           *p = 'z';
           while (*p > 'a' && os_path_exists(*backupp)) {