vim-patch:9.1.0569: fnamemodify() treats ".." and "../" differently (#29673)

Problem:  fnamemodify() treats ".." and "../" differently.
Solution: Expand ".." properly like how "/.." is treated in 8.2.3388.
          (zeertzjq)

closes: vim/vim#15218

1ee7420460
(cherry picked from commit 028dd3c5c4)

src/nvim/path.c

@@ -2384,9 +2384,13 @@ static int path_to_absolute(const char *fname, char *buf, size_t len, int force)
       p = strrchr(fname, '\\');
     }
 #endif
+    if (p == NULL && strcmp(fname, "..") == 0) {
+      // Handle ".." without path separators.
+      p = fname + 2;
+    }
     if (p != NULL) {
-      if (strcmp(p + 1, "..") == 0) {
+      if (vim_ispathsep_nocolon(*p) && strcmp(p + 1, "..") == 0) {
-        // for "/path/dir/.." include the "/.."
+        // For "/path/dir/.." include the "/..".
         p += 3;
       }
       assert(p >= fname);

test/old/testdir/test_findfile.vim

@@ -107,6 +107,9 @@ func Test_findfile()
   let l = findfile('bar', ';../', -1)
   call assert_equal(1, len(l))
   call assert_match('.*/Xfinddir1/Xdir2/Xdir3/bar', l[0])
+  let l = findfile('bar', ';..', -1)
+  call assert_equal(1, len(l))
+  call assert_match('.*/Xfinddir1/Xdir2/Xdir3/bar', l[0])
 
   let l = findfile('bar', ';' . save_dir . '/Xfinddir1/Xdir2/', -1)
   call assert_equal(1, len(l))
@@ -117,6 +120,9 @@ func Test_findfile()
   let l = findfile('bar', ';../../', -1)
   call assert_equal(1, len(l))
   call assert_match('.*/Xfinddir1/Xdir2/Xdir3/bar', l[0])
+  let l = findfile('bar', ';../..', -1)
+  call assert_equal(1, len(l))
+  call assert_match('.*/Xfinddir1/Xdir2/Xdir3/bar', l[0])
 
   let l = findfile('bar', ';' . save_dir . '/Xfinddir1/', -1)
   call assert_equal(2, len(l))
@@ -130,6 +136,10 @@ func Test_findfile()
   call assert_equal(2, len(l))
   call assert_match('.*/Xfinddir1/Xdir2/Xdir3/bar', l[0])
   call assert_match('.*/Xfinddir1/bar',             l[1])
+  let l = findfile('bar', ';../../..', -1)
+  call assert_equal(2, len(l))
+  call assert_match('.*/Xfinddir1/Xdir2/Xdir3/bar', l[0])
+  call assert_match('.*/Xfinddir1/bar',             l[1])
 
   " Test combined downwards and upwards search from Xdir2/.
   cd ../..

test/old/testdir/test_fnamemodify.vim

@@ -14,6 +14,8 @@ func Test_fnamemodify()
   call assert_equal($HOME .. "/foo" , fnamemodify('~/foo', ':p'))
   call assert_equal(fnamemodify('.', ':p:h:h:h') .. '/', fnamemodify($HOME .. '/../', ':p'))
   call assert_equal(fnamemodify('.', ':p:h:h:h') .. '/', fnamemodify($HOME .. '/..', ':p'))
+  call assert_equal(fnamemodify('.', ':p:h:h') .. '/', fnamemodify('../', ':p'))
+  call assert_equal(fnamemodify('.', ':p:h:h') .. '/', fnamemodify('..', ':p'))
   call assert_equal('test.out', fnamemodify('test.out', ':.'))
   call assert_equal('a', fnamemodify('../testdir/a', ':.'))
   call assert_equal('~/testdir/test.out', fnamemodify('test.out', ':~'))

test/old/testdir/test_taglist.vim

@@ -143,15 +143,15 @@ func Test_tagfiles_stopdir()
   call writefile([], 'Xtagsdir1/Xtags', 'D')
 
   cd Xtagsdir1/
-  let &tags = './Xtags;' .. fnamemodify('./..', ':p')
+  let &tags = './Xtags;' .. fnamemodify('..', ':p')
   call assert_equal(1, len(tagfiles()))
 
   cd Xtagsdir2/
-  let &tags = './Xtags;' .. fnamemodify('./..', ':p')
+  let &tags = './Xtags;' .. fnamemodify('..', ':p')
   call assert_equal(1, len(tagfiles()))
 
   cd Xtagsdir3/
-  let &tags = './Xtags;' .. fnamemodify('./..', ':p')
+  let &tags = './Xtags;' .. fnamemodify('..', ':p')
   call assert_equal(0, len(tagfiles()))
 
   let &tags = './Xtags;../'
@@ -163,6 +163,15 @@ func Test_tagfiles_stopdir()
   cd ..
   call assert_equal(1, len(tagfiles()))
 
+  let &tags = './Xtags;..'
+  call assert_equal(1, len(tagfiles()))
+
+  cd Xtagsdir2/
+  call assert_equal(1, len(tagfiles()))
+
+  cd Xtagsdir3/
+  call assert_equal(0, len(tagfiles()))
+
   set tags&
   call chdir(save_cwd)
 endfunc

test/unit/path_spec.lua

@@ -468,8 +468,11 @@ describe('path.c', function()
       eq(OK, result)
     end)
 
-    itp('concatenates directory name if it does not contain a slash', function()
+    itp('produces absolute path for .. without a slash', function()
-      local expected = uv.cwd() .. '/..'
+      local old_dir = uv.cwd()
+      uv.chdir('..')
+      local expected = uv.cwd()
+      uv.chdir(old_dir)
       local filename = '..'
       local buflen = get_buf_len(expected, filename)
       local do_expand = 1
@@ -478,21 +481,18 @@ describe('path.c', function()
       eq(OK, result)
     end)
 
-    itp(
+    itp('produces absolute path if possible and if path contains a slash', function()
-      'enters given directory (instead of just concatenating the strings) if possible and if path contains a slash',
+      local old_dir = uv.cwd()
-      function()
+      uv.chdir('..')
-        local old_dir = uv.cwd()
+      local expected = uv.cwd() .. '/test.file'
-        uv.chdir('..')
+      uv.chdir(old_dir)
-        local expected = uv.cwd() .. '/test.file'
+      local filename = '../test.file'
-        uv.chdir(old_dir)
+      local buflen = get_buf_len(expected, filename)
-        local filename = '../test.file'
+      local do_expand = 1
-        local buflen = get_buf_len(expected, filename)
+      local buf, result = vim_FullName(filename, buflen, do_expand)
-        local do_expand = 1
+      eq(expected, ffi.string(buf))
-        local buf, result = vim_FullName(filename, buflen, do_expand)
+      eq(OK, result)
-        eq(expected, ffi.string(buf))
+    end)
-        eq(OK, result)
-      end
-    )
 
     itp('just copies the path if it is already absolute and force=0', function()
       local absolute_path = '/absolute/path'