runtime(netrw): "O" in a local listing does not copy the file

Problem:  Pressing "O" in a local listing reports "cannot determine
          method" instead of copying the file to the current directory
          as documented in |netrw-O|.
Solution: Use the islocal argument of netrw#Obtain() instead of
          b:netrw_islocal, and copy the files from b:netrw_curdir.

b:netrw_islocal is only set when a file is marked while other files are
already marked, so without marks netrw#Obtain() took the remote branch.
The names in the listing are relative to b:netrw_curdir, which is not
vim's current directory when netrw obtains a file, so the local copy
command could not find them.

related: #21534

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Yoko Davis <56965728+revesis@users.noreply.github.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/pack/dist/opt/netrw/autoload/netrw.vim

@@ -964,10 +964,12 @@ function netrw#Obtain(islocal,fname,...)
     let tgtdir= getcwd()
   endif
 
-  if exists("b:netrw_islocal") && b:netrw_islocal
+  if a:islocal
     " obtain a file from local b:netrw_curdir to (local) tgtdir
     if exists("b:netrw_curdir") && getcwd() != b:netrw_curdir
       let topath = netrw#fs#ComposePath(tgtdir,"")
+      " names in the listing are relative to b:netrw_curdir, not to vim's current directory
+      let fnamelist = map(copy(fnamelist), {_, fname -> isabsolutepath(fname) ? fname : netrw#fs#ComposePath(b:netrw_curdir, fname)})
       if has("win32") && !g:netrw_cygwin
         " transfer files one at time
         for fname in fnamelist

src/testdir/test_plugin_netrw.vim

@@ -691,6 +691,37 @@ func Test_netrw_obtain_reject_evil_hostname()
   endtry
 endfunc
 
+" "O" in a local listing copies the file under the cursor to the current directory
+func Test_netrw_obtain_local()
+  let dir = getcwd() .. '/Xnetrwobtain'
+  call mkdir(dir, 'pR')
+  call writefile(['obtained'], dir .. '/Xobtainfile')
+  try
+    exe 'Explore' dir
+    call search('^Xobtainfile$')
+    let msg = execute('normal O')
+    call assert_notmatch('cannot determine method', msg)
+    call assert_equal(['obtained'], readfile('Xobtainfile'))
+
+    " the same for marked files
+    call delete('Xobtainfile')
+    call writefile(['marked'], dir .. '/Xobtainmarked')
+    Explore
+    call search('^Xobtainfile$')
+    normal mf
+    call search('^Xobtainmarked$')
+    normal mf
+    let msg = execute('normal O')
+    call assert_notmatch('cannot determine method', msg)
+    call assert_equal(['obtained'], readfile('Xobtainfile'))
+    call assert_equal(['marked'], readfile('Xobtainmarked'))
+  finally
+    bwipe!
+    call delete('Xobtainfile')
+    call delete('Xobtainmarked')
+  endtry
+endfunc
+
 func Test_netrw_hostname()
   let valid_hostnames = [
   \   'localhost',