Print out exact sbt command to regenerate caches

Author: JaroslavTulach

.vscode/launch.json

@@ -41,6 +41,16 @@
       "name": "Rust Gen CI",
       "program": "${workspaceFolder}/target/rust/debug/enso-build-ci-gen",
       "args": []
-    }
+    },
+   {
+      "type": "lldb",
+      "request": "launch",
+      "preLaunchTask": "Rust ./run",
+      "name": "Rust ./run",
+      "program": "${workspaceFolder}/target/rust/buildscript/enso-build-cli",
+      // provide arguments, for example: 
+      "args": ["backend", "stdlib-api-check"]
+      // "args": [] 
+    },
   ]
 }

.vscode/tasks.json

@@ -13,6 +13,19 @@
 				"isDefault": true
 			},
 			"label": "Rust Gen CI"
+		},
+		{
+			"type": "cargo",
+			"command": "build",
+			"args": ["--profile", "buildscript", "-p", "enso-build-cli"],
+			"problemMatcher": [
+				"$rustc"
+			],
+			"group": {
+				"kind": "build",
+				"isDefault": true
+			},
+			"label": "Rust ./run"
 		}
 	]
 }

build_tools/build/src/engine/context.rs

@@ -620,7 +620,8 @@ impl RunContext {
         assert!(old_api_dir.exists());
         debug!(
             "Checking API for library Standard.{}, its API dir is in {:?}",
-            lib.name, old_api_dir
+            lib.name,
+            self.short_path(&old_api_dir)
         );
         // `lib_path_in_built_distribution` points to the lib in the `built-distribution`
         // directory, which is not under VCS. We will regenerate the API in this directory
@@ -645,23 +646,27 @@ impl RunContext {
         match diff {
             Ok(_) => Ok(()),
             Err(err) => {
-                let suggested_cmd = built_enso
-                    .cmd()?
-                    .with_arg("--docs")
-                    .with_arg("api")
-                    .with_arg("--in-project")
-                    .with_arg(lib.path.clone());
                 error!("API check failed for library Standard.{}", lib.name);
                 error!("Current API vs Old API: {}", err);
-                error!("If you wish to overwrite the current API in the directory {}, run the following command {},
+                error!("If you wish to overwrite the current API in the directory {}, run the following command 
+                       sbt \"runEngineDistribution --no-ir-caches --docs=api --in-project {}\"
                        and commit the modified files",
-                  old_api_dir.display(),
-                  suggested_cmd.describe()
+                  self.short_path(&old_api_dir).display(),
+                  self.short_path(&lib.path).display()
                 );
                 bail!("API check failed for library Standard.{}", lib.name);
             }
         }
     }
+
+    fn short_path(&self, full: &PathBuf) -> PathBuf {
+        let strip = full.strip_prefix(self.repo_root.path.clone());
+        if let Ok(relative) = strip {
+            relative.to_path_buf()
+        } else {
+            full.clone()
+        }
+    }
 }
 
 #[derive(Debug)]