Add exception handling and split VCS script.

This way the script is more modular.

Author: dhebbeker

define_vsc_id_macro.py

@@ -0,0 +1,21 @@
+"""
+generate_vcs_identifier.py
+
+This script adds a CPP definition of a version identifier using version control
+system information. It retrieves the VCS identifier from the 'vcs_utils' module
+and appends it to the PlatformIO build environment as a preprocessor definition
+if available.
+
+This script should be loaded by PlatformIO during the project build and is not
+designed to be run independently.
+"""
+
+from vcs_utils import get_vcs_id
+Import("env")
+
+# Get the VCS ID and conditionally append it to the environment definitions
+vcs_id = get_vcs_id()
+if vcs_id:  # Only append if a valid VCS ID is retrieved
+    env.Append(CPPDEFINES=[
+        ("VCS_ID", env.StringifyMacro(vcs_id)),
+    ])

generate_vcs_identifier.py

@@ -0,0 +1,27 @@
+import subprocess
+import sys
+
+def get_vcs_id():
+    """
+    Attempts to retrieve the VCS identifier using the 'git describe' command.
+
+    Uses git to retrieve the version control system (VCS) identifier.
+    It is designed to handle cases where Git is not installed or the current
+    directory is not a Git repository, without raising exceptions.
+    
+    Returns:
+        str: A string containing the VCS identifier if successful, or an empty 
+             string if Git is not available or the directory is not a Git repository.
+    
+    All warnings are printed to stderr.
+    """
+    try:
+        vcs_output = subprocess.run(
+            ["git", "describe", "--always", "--dirty", "--all", "--long"],
+            stdout=subprocess.PIPE, text=True, check=True
+        )
+        vcs_string = vcs_output.stdout.strip()
+        return vcs_string
+    except (subprocess.CalledProcessError, FileNotFoundError) as e:
+        print("Warning: Unable to retrieve VCS description. Error:", str(e), file=sys.stderr)
+        return ""

get_vcs_identifier.py

@@ -22,7 +22,7 @@ build_flags =
 	-DBAUD_RATE=${this.monitor_speed}
 monitor_speed = 115200
 extra_scripts =
-	pre:generate_vcs_identifier.py
+	pre:get_vcs_identifier.py
 
 [env:native]
 platform = native