Merge #3247

3247: Improve RA version display r=matklad a=edwin0cheng

There are 2 problems of current implementation for displaying current version of RA binary:

1. If that binary is coming from built by source, the `REV` may not be updated somehow. (See discussion in [Zuilp](https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Fwg-rls-2.2E0/topic/vscode.20version.20in.20console))

2. We must go through the VSCode debugger console to see the output of `console.log`.

This PR implemented a new VSCode command "Show RA Version" to display the version, which  fixed the first problem.  And added some `rerun-if` flags in `build.rs` to fix the second one.

Co-authored-by: Edwin Cheng <[email protected]>

3 files changed, 23 insertions, 0 deletions

diff --git a/editors/code/src/commands/index.ts b/editors/code/src/commands/index.ts
index bebd99ca9..839245f48 100644
--- a/editors/code/src/commands/index.ts
+++ b/editors/code/src/commands/index.ts
@@ -13,6 +13,7 @@ export * from './syntax_tree';
 export * from './expand_macro';
 export * from './runnables';
 export * from './ssr';
+export * from './server_version';
 
 export function collectGarbage(ctx: Ctx): Cmd {
     return async () => {
diff --git a/editors/code/src/commands/server_version.ts b/editors/code/src/commands/server_version.ts
new file mode 100644
index 000000000..421301b42
--- /dev/null
+++ b/editors/code/src/commands/server_version.ts
@@ -0,0 +1,21 @@
+import * as vscode from 'vscode';
+import { ensureServerBinary } from '../installation/server';
+import { Ctx, Cmd } from '../ctx';
+import { spawnSync } from 'child_process';
+
+export function serverVersion(ctx: Ctx): Cmd {
+    return async () => {
+        const binaryPath = await ensureServerBinary(ctx.config.serverSource);
+
+        if (binaryPath == null) {
+            throw new Error(
+                "Rust Analyzer Language Server is not available. " +
+                "Please, ensure its [proper installation](https://rust-analyzer.github.io/manual.html#installation)."
+            );
+        }
+
+        const version = spawnSync(binaryPath, ["--version"], { encoding: "utf8" }).stdout;
+        vscode.window.showInformationMessage('rust-analyzer version : ' + version);
+    };
+}
+
diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index a22e0bc66..de19a44e5 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -55,6 +55,7 @@ export async function activate(context: vscode.ExtensionContext) {
     ctx.registerCommand('run', commands.run);
     ctx.registerCommand('onEnter', commands.onEnter);
     ctx.registerCommand('ssr', commands.ssr);
+    ctx.registerCommand('serverVersion', commands.serverVersion);
 
     // Internal commands which are invoked by the server.
     ctx.registerCommand('runSingle', commands.runSingle);