Add base simulator handling logic (#112)

Author: rockbruno

Example/.vscode/tasks.json

@@ -2,55 +2,33 @@
   "version": "2.0.0",
   "tasks": [
     {
-      "label": "Build HelloWorld",
+      "label": "Select Simulator for Apple Development",
       "type": "shell",
-      "command": "bazelisk",
-      "args": [
-        "build",
-        "//HelloWorld"
-      ],
-      "group": {
-        "kind": "build",
-        "isDefault": true
+      "command": "./scripts/select_simulator.sh",
+      "presentation": {
+        "reveal": "always",
+        "focus": true,
+        "panel": "dedicated"
       },
-      "problemMatcher": [
-        {
-          "owner": "swift",
-          "source": "swift",
-          "fileLocation": [
-            "relative",
-            "${workspaceFolder}"
-          ],
-          "pattern": {
-            "regexp": "^(.+?):(\\d+):(\\d+):\\s+(error|warning|note):\\s+(.*)$",
-            "file": 1,
-            "line": 2,
-            "column": 3,
-            "severity": 4,
-            "message": 5
-          }
-        },
-      ],
-      "runOptions": {
-        "instanceLimit": 1
-      }
+      "problemMatcher": []
     },
     {
-      "label": "Test HelloWorldTests",
+      "label": "Build HelloWorld",
       "type": "shell",
-      "command": "bazelisk",
-      "args": [
-        "test",
-        "//HelloWorld:HelloWorldTests"
-      ],
+      "command": "./scripts/lldb_build.sh",
+      "options": {
+        "env": {
+          "BAZEL_LABEL_TO_RUN": "//HelloWorld:HelloWorld",
+          "BAZEL_EXTRA_BUILD_FLAGS": "",
+        }
+      },
       "group": {
-        "kind": "test",
-        "isDefault": true
+        "kind": "build",
       },
       "problemMatcher": [
         {
-          "owner": "swift",
-          "source": "swift",
+          "owner": "bazelisk",
+          "source": "bazelisk",
           "fileLocation": [
             "relative",
             "${workspaceFolder}"
@@ -62,12 +40,9 @@
             "column": 3,
             "severity": 4,
             "message": 5
-          }
+          },
         },
       ],
-      "runOptions": {
-        "instanceLimit": 1
-      }
     },
     // Hidden never-ending task that handles the launch / debugging bits for Cmd+Shift+D.
     // The problemMatcher field defines when the task is effectively ready to be debugged
@@ -78,7 +53,9 @@
       "command": "./scripts/lldb_launch_and_debug.sh",
       "options": {
         "env": {
-          "BAZEL_LABEL_TO_RUN": "//HelloWorld:HelloWorld"
+          "BAZEL_LABEL_TO_RUN": "//HelloWorld:HelloWorld",
+          "BAZEL_EXTRA_BUILD_FLAGS": "",
+          "BAZEL_LAUNCH_ARGS": ""
         }
       },
       "presentation": {
@@ -88,40 +65,49 @@
       "isBackground": true,
       "problemMatcher": [
         {
-          "owner": "swift",
-          "source": "swift",
+          "owner": "bazelisk",
+          "source": "bazelisk",
           "fileLocation": [
             "relative",
             "${workspaceFolder}"
           ],
           "pattern": {
-            "regexp": "^(.+?):(\\d+):(\\d+):\\s+(error|warning|note):\\s+(.*)$",
-            "file": 1,
-            "line": 2,
-            "column": 3,
-            "severity": 4,
-            "message": 5
+              "regexp": "launcher_error in (.*): (.*)",
+              "kind": "file",
+              "file": 1,
+              "message": 2,
+          },
+          "background": {
+            "activeOnStart": true,
+            "beginsPattern": "^Starting launch task\\.\\.\\.$",
+            "endsPattern": "^.*Launched with PID: .*"
           }
         },
         {
-          "pattern": [
-            {
-              "regexp": "\\b\\B",
-              "file": 1,
-              "location": 2,
-              "message": 3
-            }
+          "owner": "bazelisk",
+          "source": "bazelisk",
+          "fileLocation": [
+            "relative",
+            "${workspaceFolder}"
           ],
+          "pattern": {
+              "regexp": "^(.+?):(\\d+):(\\d+):\\s+(error|warning|note):\\s+(.*)$",
+              "file": 1,
+              "line": 2,
+              "column": 3,
+              "severity": 4,
+              "message": 5
+          },
           "background": {
             "activeOnStart": true,
-            "beginsPattern": "^.*Building .*",
+            "beginsPattern": "^Starting launch task\\.\\.\\.$",
             "endsPattern": "^.*Launched with PID: .*"
           }
-        }
+        },
       ],
       "runOptions": {
         "instanceLimit": 1
       }
-    }
+    },
   ]
 }

Example/README.md

@@ -1,13 +1,14 @@
 # Example (Cursor/VSCode)
 
-This is a simple **iOS** app that lets you see sourcekit-bazel-bsp in action. This example and instructions were designed specifically for **Cursor**, but should also work for VSCode.
+This is a simple collection of iOS/watchOS/macOS apps that lets you see sourcekit-bazel-bsp in action. This example and instructions were designed specifically for **Cursor**, but should also work for VSCode.
 
 ## Initial Setup Instructions
 
 - Make sure you fulfill the toolchain requirements for sourcekit-bazel-bsp, available at the main README.
-- Install [bazelisk](https://github.com/bazelbuild/bazelisk) if you haven't already.
-  - On macOS: `brew install bazelisk`
+- Install [bazelisk](https://github.com/bazelbuild/bazelisk) if you haven't already: `brew install bazelisk`
   - Make sure you're using **Xcode 26** as this is what this project was developed with.
+- Install [fzf](https://github.com/junegunn/fzf) if you haven't already: `brew install fzf`
+  - This is used to power the simulator selection features.
 - On this folder, run:
   - `bazelisk run //HelloWorld:setup_sourcekit_bsp_example_project`
 - (Optional) Follow the instructions from the main README regarding configuring a custom SourceKit-LSP binary.
@@ -17,12 +18,12 @@ This is a simple **iOS** app that lets you see sourcekit-bazel-bsp in action. Th
 
 After performing these steps, you should already be able to see the basic indexing features in action. It may take a minute or two the first time, but you can see the progress at the bottom of the IDE. You should also be able to see a new `SourceKit Language Server` option on the `Output` tab that shows sourcekit-lsp's internal logs, and after modifying a file for the first time an additional `SourceKit-LSP: Indexing` tab will pop up containing more detailed logs from both tools.
 
-## Building and Testing
+## Building and Debugging
 
-- To run a regular build: Cmd+Shift+B -> `Build HelloWorld`
-- To run a debug build, launch the simulator and attach `lldb`: Cmd+Shift+D -> `Debug HelloWorld (Example)`
-  - This requires a **iOS 18.6 iPhone 16 Pro** simulator installed as this is what the example project is currently configured for. Make sure you have one available, as otherwise the build will fail.
-- To test: Cmd+Shift+P -> `Run Test Task` -> `Test HelloWorldTests`
+- To build the example iOS app: `Terminal` -> `Run Build Task...` -> `Build HelloWorld`
+- To run a debug build, launch a simulator and attach `lldb`:
+  - First, select an appropriate iOS simulator via `Terminal` -> `Run Task...` -> `Select Simulator for Apple Development`. The minimum OS version of the example app is **iOS 17.0**.
+  - Then: Cmd+Shift+D -> `Debug HelloWorld (Example)`. After building, the IDE will automatically launch your selected simulator and attach it to the IDE's lldb extension.
 
 ## Considerations
 

Example/scripts/lldb_build.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+source "scripts/lldb_build_common.sh"
+run_bazel "build"

Example/scripts/lldb_build_common.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+# Stores common functionality for build and launch tasks.
+
+set -e
+
+export WORKSPACE_ROOT
+WORKSPACE_ROOT=$(pwd)
+
+export ADDITIONAL_FLAGS=()
+ADDITIONAL_FLAGS+=("--keep_going")
+ADDITIONAL_FLAGS+=("--color=yes")
+
+if [ -n "${BAZEL_EXTRA_BUILD_FLAGS:-}" ]; then
+  ADDITIONAL_FLAGS+=("${BAZEL_EXTRA_BUILD_FLAGS[@]}")
+fi
+
+LAUNCH_ARGS_ARRAY=()
+if [ -n "${BAZEL_LAUNCH_ARGS:-}" ]; then
+  read -ra LAUNCH_ARGS_ARRAY <<< "$BAZEL_LAUNCH_ARGS"
+fi
+
+function run_bazel() {
+  local command="$1"
+  bazelisk "${command}" "${BAZEL_LABEL_TO_RUN}" "${ADDITIONAL_FLAGS[@]}" ${LAUNCH_ARGS_ARRAY[@]:+-- "${LAUNCH_ARGS_ARRAY[@]}"}
+}

Example/scripts/lldb_launch_and_debug.sh

@@ -1,10 +1,23 @@
 #!/bin/bash
 
-set -e
+source "scripts/lldb_build_common.sh"
 
-echo "Building ${BAZEL_LABEL_TO_RUN}..."
+echo "Starting launch task..."
 
-WORKSPACE_ROOT=$(pwd)
+function emit_launcher_error() {
+  echo "launcher_error in ${BASH_SOURCE[0]}: ${1}"
+  exit 1
+}
+
+# Read information regarding the user's selected simulator.
+SIMULATOR_INFO_FILE=${WORKSPACE_ROOT}/.bsp/skbsp_generated/simulator_info.txt
+SIMULATOR_INFO=""
+if [ -f "${SIMULATOR_INFO_FILE}" ]; then
+  SIMULATOR_INFO=$(cat "${SIMULATOR_INFO_FILE}")
+  echo "Will use simulator: ${SIMULATOR_INFO}"
+else
+  emit_launcher_error "No simulator selected! You need to first run the 'Select Simulator for Apple Development' task before being able to run this script."
+fi
 
 # When asking Bazel to launch a simulator, we need to intercept
 # the launched process' PID to be able to debug it later on.
@@ -24,20 +37,32 @@ cat > ${BAZEL_INFO_JSON} <<EOF
 }
 EOF
 
-ADDITIONAL_FLAGS=()
-ADDITIONAL_FLAGS+=("--keep_going")
-ADDITIONAL_FLAGS+=("--color=yes")
 # We need --remote_download_regex because the files that lldb needs won't usually be downloaded by Bazel
 # when using flags like --remote_download_toplevel and the such.
 ADDITIONAL_FLAGS+=("--remote_download_regex=.*\.indexstore/.*|.*\.(a|cfg|c|C|cc|cl|cpp|cu|cxx|c++|def|h|H|hh|hpp|hxx|h++|hmap|ilc|inc|inl|ipp|tcc|tlh|tli|tpp|m|modulemap|mm|pch|swift|swiftdoc|swiftmodule|swiftsourceinfo|yaml)$")
+ADDITIONAL_FLAGS+=("--@build_bazel_rules_apple//apple/build_settings:ios_device=${SIMULATOR_INFO}")
 
 BAZEL_APPLE_PREFER_PERSISTENT_SIMS=1 \
-BAZEL_APPLE_LAUNCH_INFO_PATH=${LAUNCH_INFO_JSON} \
+BAZEL_APPLE_LAUNCH_INFO_PATH="${LAUNCH_INFO_JSON}" \
 BAZEL_SIMCTL_LAUNCH_FLAGS="--wait-for-debugger --stdout=$(tty) --stderr=$(tty)" \
-bazelisk run "${BAZEL_LABEL_TO_RUN}" "${ADDITIONAL_FLAGS[@]}"
+run_bazel "run"
+
+# Remove the default lldbinit file created by rules_xcodeproj if it exists.
+# This prevents Xcode details from leaking over to our builds.
+# It's safe to delete this because rules_xcodeproj creates it on every build.
+RULES_XCODEPROJ_LLDBINIT_FILE=${HOME}/.lldbinit-rules_xcodeproj
+if [ -f "${RULES_XCODEPROJ_LLDBINIT_FILE}" ]; then
+  echo "Removing rules_xcodeproj's lldbinit file..."
+  rm -f "${RULES_XCODEPROJ_LLDBINIT_FILE}" || true
+fi
 
 PID=$(jq -r '.pid' "${LAUNCH_INFO_JSON}")
 
+if [ -z "${PID}" ]; then
+  emit_launcher_error "No PID found in ${LAUNCH_INFO_JSON}"
+fi
+
+# Note: This string is hardcoded in tasks.json file to launch LLDB-DAP.
 echo "Launched with PID: ${PID}"
 
 # Keep the terminal alive until the app is killed.

Example/scripts/select_simulator.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+
+set -e
+
+# Script that displays all available simulators to the user
+# and writes the selected one's UUID to a file. This file
+# is then parsed by lldb_launch_and_debug.sh to pass the
+# appropriate device flags to Bazel.
+
+WORKSPACE_ROOT=$(pwd)
+OUTPUT_FILE=${WORKSPACE_ROOT}/.bsp/skbsp_generated/simulator_info.txt
+
+# Get list of all available simulators with their UDIDs
+# Format: "Device Name (platform X.Y) - UDID"
+SIMULATORS=$(xcrun simctl list devices available -j | jq -r '
+  .devices | to_entries[] |
+  .key as $runtime |
+  .value[] |
+  ($runtime | split("SimRuntime.")[1] | split("-") | "\(.[0]) \(.[1]).\(.[2])") as $version |
+  "\(.name) (\($version)) - \(.udid)"
+' | sort)
+
+if [ -z "$SIMULATORS" ]; then
+  echo "error: No available simulators found."
+  exit 1
+fi
+
+# Check if fzf is available
+if ! command -v fzf &> /dev/null; then
+  echo "error: You need \`fzf\` to run this script. You can install it with 'brew install fzf'."
+  exit 1
+fi
+
+SELECTED=$(echo "$SIMULATORS" | fzf --height=20 --reverse --prompt="Select the simulator you'd like to use: ")
+
+if [ -z "$SELECTED" ]; then
+  echo "error: No simulator selected."
+  exit 1
+fi
+
+# Extract the UUID from the selection (split(" - ")[1])
+UUID=$(echo "$SELECTED" | awk -F' - ' '{print $2}')
+
+mkdir -p "$(dirname "$OUTPUT_FILE")" || true
+echo -n "$UUID" > "$OUTPUT_FILE"
+
+echo "Selected simulator: $SELECTED"
+echo "UUID ($UUID) successfully written to: $OUTPUT_FILE"
+echo "The selected simulator will now be used for your future builds."

README.md

@@ -12,7 +12,7 @@
 - [x] All of the usual indexing features such as code completion, jump to definition, error annotations and so on, for both Swift and Obj-C (via the official [sourcekit-lsp](https://github.com/swiftlang/sourcekit-lsp))
 - [x] (Cursor / VSCode): Building and launching, all from within the IDE and directly via Bazel (no project generation required!)
 - [x] (Cursor / VSCode): Full `lldb` integration, allowing debugging from within the IDE just like Xcode (via [lldb-dap](https://marketplace.visualstudio.com/items?itemName=llvm-vs-code-extensions.lldb-dap), automatically provided by the official Swift extension)
-- [ ] (Cursor / VSCode): Simulator selection from within the IDE
+- [x] (Cursor / VSCode): Simulator selection from within the IDE (via custom IDE tasks)
 - [ ] (Cursor / VSCode): Automatic generation of build, launch, and debug tasks
 - [ ] (Cursor / VSCode): Test explorer & ability to run tests from within the IDE by clicking the tests individually, similarly to Xcode
 - [ ] Automatic index and build graph updates when adding / deleting files and targets (in other words, allowing the user to make heavy changes to the project without needing to restart the IDE)
@@ -76,6 +76,12 @@ The BSP by default works by attempting to build your library targets individuall
 
 If this is undesirable, you can pass the `--compile-top-level` flag to make the BSP compile the target's **parent** instead, without any special flags. We recommend using this for projects that define fine-grained `*_build_test` targets and providing them as top-level targets for the BSP, as those don't suffer from this issue and thus enables maximum predictability and cacheability.
 
+## Best Practices
+
+- When working with large apps, consider being more explicit about the task you're going to do. This means that instead of importing the _entire app at all times_, try to import only a small group of test targets that you think will be required to perform the task. This will greatly increase the performance of the IDE.
+    - For smaller apps, this doesn't make much difference and it should be fine to import the entire app.
+- Similarly, avoid wide-reaching wildcards like `//...`. Do so only at a smaller scale to avoid too many targets from being picked up.
+
 ## Troubleshooting
 
 ### Seeing sourcekit-bazel-bsp's logs