[lldb/Commands] Fix disk completion from root directory

[mib]

Summary

This patch should fix path completion starting from the root directory.

To do so, this patch adds a special case when setting the search
directory when the completion buffer points to the root directory.

Signed-off-by: Med Ismail Bennani <[e-mail]>

[bulbazord]

The change itself looks ok to me. Could you add a test for this? We do have some tests to test for completion so the machinery is there, but it's mostly for the expression evaluator right now.

[mib]

Add test

[bulbazord]

lldb/test/API/functionalities/completion/TestCompletion.py

439–450 ↗

(On Diff #528058)

I'm curious to know if this will work for windows? I don't know how lldb treats / as a path when on a windows host.

root_dir should be os.path.abspath('\\') on windows, which might give you C:\ or whatever the current drive is, so that path might possibly give you something? Idk, you might have to fiddle with the test to get it to work correctly or disable it.

[mib]

lldb/test/API/functionalities/completion/TestCompletion.py

439–450 ↗

(On Diff #528058)

I don't have a windows machine to try this on (some help would be appreciated here :p) but os.path.abspath(os.sep) should cover that part.

[mib]

Address @bulbazord comments!

[bulbazord]

Ok, this looks fine to me. I'm not 100% sure this will work on Windows, but we neither Ismail nor I have windows machines to test this on. Watch the windows bots please.

lldb/source/Commands/CommandCompletions.cpp

if (CompletionBuffer.startswith("~")) {
     Storage = Resolved;
     llvm::StringRef RemainderDir = path::parent_path(Remainder);
     if (!RemainderDir.empty()) {
       // Append the remaining path to the resolved directory.
       Storage.append(path::get_separator());
       Storage.append(RemainderDir);
     }
     SearchDir = Storage;
+  } else if (CompletionBuffer == path::root_directory(CompletionBuffer)) {
+    SearchDir = CompletionBuffer;
   } else {
     SearchDir = path::parent_path(CompletionBuffer);
   }
 
   size_t FullPrefixLen = CompletionBuffer.size();
 
   PartialItem = path::filename(CompletionBuffer);
 
   // path::filename() will return "." when the passed path ends with a
-  // directory separator. We have to filter those out, but only when the
-  // "." doesn't come from the completion request itself.
-  if (PartialItem == "." && path::is_separator(CompletionBuffer.back()))
+  // directory separator or the separator when passed the disk root directory.
+  // We have to filter those out, but only when the "." doesn't come from the
+  // completion request itself.
+  if ((PartialItem == "." || PartialItem == path::get_separator()) &&
+      path::is_separator(CompletionBuffer.back()))
     PartialItem = llvm::StringRef();
 
   if (SearchDir.empty()) {
     llvm::sys::fs::current_path(Storage);
     SearchDir = Storage;
   }
   assert(!PartialItem.contains(path::get_separator()));