Make it clear to contributors LLDB is needed for doc generation (#3057)

* inform user in setup-dev. bail the docs scripts if necessary.

* make note about both debuggers being installed in the docs

docs/contributing/index.md

@@ -82,7 +82,7 @@ The `./docs/commands`, `./docs/functions`, and `./docs/configuration` folders ar
 ```{.bash .copy}
 ./scripts/generate-docs.sh
 ```
-to update the documentation. Commit these changes in a separate commit.
+to update the documentation. You need to have a supported version of GDB *and* [LLDB installed](setup-pwndbg-dev.md#running-with-lldb) for this to work. Commit these changes in a separate commit.
 
 If you forget to do that the CI will detect a discrepency between the documentation and source code (using the `./scripts/verify-docs.sh` script, which you may also invoke yourself) and prevent your PR from being merged (until you push new changes, re-running the CI).
 

docs/contributing/setup-pwndbg-dev.md

@@ -65,6 +65,9 @@ After installing Pwndbg like described above, there are a few ways to set up the
 ```
 but you can also use the [docker container](#development-from-docker) or [develop using nix](#development-using-nix).
 
+!!! note
+    For a proper development environment you must be able to run Pwndbg with both GDB and LLDB, otherwise you won't be able to use some important development features (like doc generation).
+
 ### Development from docker
 You can create a Docker image with everything already installed for you. You can use docker compose
 ```{.bash .copy}

scripts/_docs/extract-all-docs.sh

@@ -1,5 +1,23 @@
 #!/usr/bin/env bash
 
+# Check that supported LLDB is installed.
+if ! command -v lldb &> /dev/null; then
+    echo "Cannot reliably extract information from sources because LLDB"
+    echo "is not installed. See installation instructions:"
+    echo "https://pwndbg.re/pwndbg/dev/contributing/setup-pwndbg-dev/#running-with-lldb"
+    exit 3
+else
+    version=$(lldb --version | awk '{print $3}')
+    major_version=${version%%.*}
+
+    if [ "$major_version" -lt 19 ]; then
+        echo "Cannot reliably extract information from sources because your LLDB"
+        echo "version (${version}) is too old. Supported is LLDB >= 19. See installation instructions:"
+        echo "https://pwndbg.re/pwndbg/dev/contributing/setup-pwndbg-dev/#running-with-lldb"
+        exit 4
+    fi
+fi
+
 source "$(dirname "$0")/../common.sh"
 
 cd $PWNDBG_ABS_PATH

setup-dev.sh

@@ -349,3 +349,25 @@ if linux; then
         configure_venv
     fi
 fi
+
+# LLDB is needed for docs generation. Tell the user
+# if they don't have it installed or if it's an unsupported version.
+if ! command -v lldb &> /dev/null; then
+    echo "WARNING: lldb not found in PATH, some functionality"
+    echo "(e.g. docs generation) will not be available."
+    echo "See installation instructions:"
+    echo "https://pwndbg.re/pwndbg/dev/contributing/setup-pwndbg-dev/#running-with-lldb"
+else
+    version=$(lldb --version | awk '{print $3}')
+    major_version=${version%%.*}
+
+    if [ "$major_version" -ge 19 ]; then
+        echo "Supported LLDB installed. All good!"
+    else
+        echo "WARNING: lldb found in PATH, but the version is too old."
+        echo "Installed: ${version}. Supported: >= 19."
+        echo "Some functionality (e.g. docs generation) will not be available."
+        echo "See installation instructions:"
+        echo "https://pwndbg.re/pwndbg/dev/contributing/setup-pwndbg-dev/#running-with-lldb"
+    fi
+fi