Fix editable installs when using extraPaths/PYTHONPATH (microsoft#1183)

* Allow interpreter paths to be reclassified as user code if specified in user search paths

* log raw search path results only in verbose mode

* update TROUBLESHOOTING

TROUBLESHOOTING.md

@@ -9,15 +9,10 @@ in [Filing an issue](#filing-an-issue).
 
 There are a few known issues in the current version of the language server:
 
-- Import statement handling may be too strict, leading to "unresolved import" messages and the lack of analysis.
-    - The language server considers the workspace root to be the root of user code imports. For the most part, this can be modified by adding additional folders to the `python.autoComplete.extraPaths` setting, for example, `"python.autoComplete.extraPaths": ["./src"]`, if `src` contains the user code. A `.env` file with `PYTHONPATH` set may also help.
-    - Editable installs (`pip install -e` or `setup.py develop`) are known not to work with `extraPaths` when the package is installed. (#1139, #1013, #1137, #989, others).
 - Not all `__all__` statements can be handled.
     - Some modules may have an incorrect list of exported names.
     See [#620](https://github.com/Microsoft/python-language-server/issues/620),
     [#619](https://github.com/Microsoft/python-language-server/issues/619).
-- Persistent issues with high memory consumption for users. 
-    - In some contexts, users are experiencing higher than average amounts of memory being consumed. See [#832](https://github.com/Microsoft/python-language-server/issues/832).
 
 
 ## Requirements
@@ -38,6 +33,47 @@ but may require outside libraries such as OpenSSL 1.0 or `libicu` on Linux.
 
 ## Common questions and issues
 
+### Unresolved import warnings
+
+If you're getting a warning about an unresolved import, first ensure that the
+package is installed into your environment if it is a library (`pip`, `pipenv`, etc).
+If the warning is about importing _your own_ code (and not a library), continue reading.
+
+The language server treats the workspace root (i.e. folder you have opened) as
+the main root of user module imports. This means that if your imports are not relative
+to this path, the language server will not be able to find them. This is common
+for users who have a `src` directory which contains their code, a directory for
+an installable package, etc.
+
+These extra roots must be specified to the language server. The easiest way to
+do this (with the VS Code Python extension) is to create a workspace configuration
+which sets `python.autoComplete.extraPaths`. For example, if a project uses a
+`src` directory, then create a file `.vscode/settings.json` in the workspace
+with the contents:
+
+
+```json
+{
+    "python.autoComplete.extraPaths": ["./src"]
+}
+```
+
+This list can be extended to other paths within the workspace (or even with
+code outside the workspace in more complicated setups). Relative paths will
+be taken as relative to the workspace root.
+
+This list may also be configured using the `PYTHONPATH` environment variable,
+either set directly, or via a `.env` file in the workspace root (if using the
+Python extension):
+
+```
+PYTHONPATH=./src
+```
+
+For more examples, see issues:
+[#1085](https://github.com/microsoft/python-language-server/issues/1085#issuecomment-492919382),
+[#1169](https://github.com/microsoft/python-language-server/issues/1169#issuecomment-499998928)
+
 ### "Server initialization failed"
 
 If you see this message, ensure that an interpreter has been selected. (See [Requirements](#requirements)).

src/Analysis/Ast/Impl/Modules/Resolution/MainModuleResolution.cs

@@ -71,16 +71,16 @@ public async Task<IReadOnlyList<string>> GetSearchPathsAsync(CancellationToken c
             Debug.Assert(_searchPaths != null, "Should have search paths");
             _searchPaths = _searchPaths ?? Array.Empty<string>();
 
-            _log?.Log(TraceEventType.Information, "Python search paths:");
+            _log?.Log(TraceEventType.Verbose, "Python search paths:");
             foreach (var s in _searchPaths) {
-                _log?.Log(TraceEventType.Information, $"    {s}");
+                _log?.Log(TraceEventType.Verbose, $"    {s}");
             }
 
             var configurationSearchPaths = Configuration.SearchPaths ?? Array.Empty<string>();
 
-            _log?.Log(TraceEventType.Information, "Configuration search paths:");
+            _log?.Log(TraceEventType.Verbose, "Configuration search paths:");
             foreach (var s in configurationSearchPaths) {
-                _log?.Log(TraceEventType.Information, $"    {s}");
+                _log?.Log(TraceEventType.Verbose, $"    {s}");
             }
             return _searchPaths;
         }
@@ -213,14 +213,25 @@ public async Task ReloadAsync(CancellationToken cancellationToken = default) {
 
             InterpreterPaths = await GetSearchPathsAsync(cancellationToken);
 
-            var userSearchPaths = _interpreter.Configuration.SearchPaths.Except(InterpreterPaths, StringExtensions.PathsStringComparer);
+            IEnumerable<string> userSearchPaths = Configuration.SearchPaths;
+            InterpreterPaths = InterpreterPaths.Except(userSearchPaths, StringExtensions.PathsStringComparer);
 
             if (Root != null) {
                 var underRoot = userSearchPaths.ToLookup(p => _fs.IsPathUnderRoot(Root, p));
                 userSearchPaths = underRoot[true];
                 InterpreterPaths = underRoot[false].Concat(InterpreterPaths);
             }
 
+            _log?.Log(TraceEventType.Information, "Interpreter search paths:");
+            foreach (var s in InterpreterPaths) {
+                _log?.Log(TraceEventType.Information, $"    {s}");
+            }
+
+            _log?.Log(TraceEventType.Information, "User search paths:");
+            foreach (var s in userSearchPaths) {
+                _log?.Log(TraceEventType.Information, $"    {s}");
+            }
+
             addedRoots.UnionWith(PathResolver.SetInterpreterSearchPaths(InterpreterPaths));
             addedRoots.UnionWith(SetUserSearchPaths(userSearchPaths));
             ReloadModulePaths(addedRoots);