Improve vscode clangd experience (#2431)

* Improve vscode clangd experience

- Resolve and use absolute path for the toolchain. This allows clangd to use compile_commands.json file without running under fbtenv, simplifies setup for vscode clangd extension. As a side effect, a rebuild is needed to update compile_commands.json after moving the source tree.
- Add the recommended default settings of the extension to settings.json.

* Use build/latest for compile-commands-dir

This makes it behave closer to c-cpp-properties.

* Reformat crosscc.py

This is a PEP-8 violation but black seems to enforce it

* Bypass --query-driver

This has some security implications as it grants clangd the ability to execute any executables anywhere while trying to probe a compiler based on CDB. However it's very hard to do this the safe and intended way without resorting to config generation due to reason listed in #2431. Besides that we already have workspace trust so what could go wrong? ;)

* Add an option for vscode_dist to switch between clangd and cpptools

This will install different extensions.json tuned for either clangd or cpptools based on user selection. It will also install c_cpp_properties.json when using cpptools since clangd doesn't use this file.

The root .gitignore now also doesn't accidentally ignore everything under the .vscode directory.

* Use absolute path for .vscode gitignore

Turns out the previously used "relative" paths aren't even valid gitignore patterns and to actually do what it means one needs to use the absolute paths instead.

* Handle variable parsing in commandline.scons

commandline.scons is the place where all other command line parsing happens. Move LANG_SERVER variable parsing there and add a constraint to make the code more consistent.

---------

Co-authored-by: hedger <hedger@users.noreply.github.com>
Co-authored-by: hedger <hedger@nanode.su>

.vscode/.gitignore

@@ -1,4 +1,5 @@
-./c_cpp_properties.json
-./launch.json
-./settings.json
-./tasks.json
+/c_cpp_properties.json
+/extensions.json
+/launch.json
+/settings.json
+/tasks.json

.vscode/example/clangd/extensions.json

@@ -0,0 +1,19 @@
+{
+	// See https://go.microsoft.com/fwlink/?LinkId=827846 to learn about workspace recommendations.
+	// Extension identifier format: ${publisher}.${name}. Example: vscode.csharp
+	// List of extensions which should be recommended for users of this workspace.
+	"recommendations": [
+		"ms-python.black-formatter",
+		"llvm-vs-code-extensions.vscode-clangd",
+		"amiralizadeh9480.cpp-helper",
+		"marus25.cortex-debug",
+		"zxh404.vscode-proto3",
+		"augustocdias.tasks-shell-input"
+	],
+	// List of extensions recommended by VS Code that should not be recommended for users of this workspace.
+	"unwantedRecommendations": [
+		"twxs.cmake",
+		"ms-vscode.cpptools",
+		"ms-vscode.cmake-tools"
+	]
+}

.vscode/example/cpptools/extensions.json

@@ -13,6 +13,7 @@
 	],
 	// List of extensions recommended by VS Code that should not be recommended for users of this workspace.
 	"unwantedRecommendations": [
+		"llvm-vs-code-extensions.vscode-clangd",
 		"twxs.cmake",
 		"ms-vscode.cmake-tools"
 	]

.vscode/example/settings.json

@@ -21,5 +21,10 @@
         "SConscript": "python",
         "SConstruct": "python",
         "*.fam": "python",
-    }
-}
+    },
+    "clangd.arguments": [
+        // We might be able to tighten this a bit more to only include the correct toolchain.
+        "--query-driver=**",
+        "--compile-commands-dir=${workspaceFolder}/build/latest"
+    ]
+}

SConstruct

@@ -45,6 +45,7 @@ distenv = coreenv.Clone(
     ],
     ENV=os.environ,
     UPDATE_BUNDLE_DIR="dist/${DIST_DIR}/f${TARGET_HW}-update-${DIST_SUFFIX}",
+    VSCODE_LANG_SERVER=ARGUMENTS.get("LANG_SERVER", "cpptools"),
 )
 
 firmware_env = distenv.AddFwProject(
@@ -348,7 +349,14 @@ distenv.PhonyTarget(
 )
 
 # Prepare vscode environment
-vscode_dist = distenv.Install("#.vscode", distenv.Glob("#.vscode/example/*"))
+VSCODE_LANG_SERVER = cmd_environment["LANG_SERVER"]
+vscode_dist = distenv.Install(
+    "#.vscode",
+    [
+        distenv.Glob("#.vscode/example/*.json"),
+        distenv.Glob(f"#.vscode/example/{VSCODE_LANG_SERVER}/*.json"),
+    ],
+)
 distenv.Precious(vscode_dist)
 distenv.NoClean(vscode_dist)
 distenv.Alias("vscode_dist", vscode_dist)

documentation/fbt.md

@@ -46,6 +46,8 @@ To run cleanup (think of `make clean`) for specified targets, add the `-c` optio
 
 `fbt` includes basic development environment configuration for VS Code. Run `./fbt vscode_dist` to deploy it. That will copy the initial environment configuration to the `.vscode` folder. After that, you can use that configuration by starting VS Code and choosing the firmware root folder in the "File > Open Folder" menu.
 
+To use language servers other than the default VS Code C/C++ language server, use `./fbt vscode_dist LANG_SERVER=<language-server>` instead. Currently `fbt` supports the default language server (`cpptools`) and `clangd`.
+
 - On the first start, you'll be prompted to install recommended plugins. We highly recommend installing them for the best development experience. _You can find a list of them in `.vscode/extensions.json`._
 - Basic build tasks are invoked in the Ctrl+Shift+B menu.
 - Debugging requires a supported probe. That includes:

scripts/fbt_tools/crosscc.py

@@ -2,6 +2,8 @@ import subprocess
 
 import gdb
 import objdump
+import shutil
+
 import strip
 from SCons.Action import _subproc
 from SCons.Errors import StopError
@@ -11,7 +13,7 @@ from SCons.Tool import ar, asm, gcc, gnulink, gxx
 def prefix_commands(env, command_prefix, cmd_list):
     for command in cmd_list:
         if command in env:
-            env[command] = command_prefix + env[command]
+            env[command] = shutil.which(command_prefix + env[command])
 
 
 def _get_tool_version(env, tool):

site_scons/commandline.scons

@@ -248,6 +248,15 @@ vars.AddVariables(
         "Full port name of Flipper to use, if multiple Flippers are connected",
         "auto",
     ),
+    EnumVariable(
+        "LANG_SERVER",
+        help="Language server type for vscode_dist.",
+        default="cpptools",
+        allowed_values=[
+            "cpptools",
+            "clangd",
+        ],
+    ),
 )
 
 Return("vars")