CFE-4667: Improve error message from cfbs about illegal characters in module names

Ticket: CFE-4667

Author: sarakthon

cfbs/validate.py

@@ -226,6 +226,7 @@ def validate_module_name_content(name):
     # lowercase ASCII alphanumericals, starting with a letter, and possible singular dashes in the middle
     r = "[a-z][a-z0-9]*(-[a-z0-9]+)*"
     proper_name = name
+    original_component = name
 
     if is_module_local(name) or is_module_absolute(name):
         # If one of these are true, the other must be false
@@ -246,6 +247,7 @@ def validate_module_name_content(name):
 
         # only validate the local module's name, not the entire path to it
         proper_name = proper_name.split("/")[-1]
+        original_component = proper_name
 
         # allow underscores, only for local and absolute modules
         proper_name = proper_name.replace("_", "-")
@@ -264,6 +266,7 @@ def validate_module_name_content(name):
         proper_name = strip_right(proper_name, "/")
         # TODO: more validation of the entire path instead of just the name (final component), since the module "name" is actually a path
         proper_name = proper_name.split("/")[-1]
+        original_component = proper_name
 
         # allow underscores, only for local and absolute modules
         proper_name = proper_name.replace("_", "-")
@@ -274,18 +277,32 @@ def validate_module_name_content(name):
             "Module name proper is empty",
         )
 
+    # builds a suggested fix for the module name
+    suggested_proper_name = re.sub(r"[^a-z0-9]+", "-", proper_name.lower()).strip("-")
+    if suggested_proper_name and re.fullmatch(r, suggested_proper_name):
+        last_idx = name.rfind(original_component)
+        suggested_name = (
+            name[:last_idx]
+            + suggested_proper_name
+            + name[last_idx + len(original_component) :]
+        )
+        suggestion = " Consider renaming it to '{}'.".format(suggested_name)
+    else:
+        suggestion = ""
+
     if proper_name[0] not in "abcdefghijklmnopqrstuvwxyz":
         raise CFBSValidationError(
             name,
-            "Module name must start with a lowercase ASCII letter ('{}' starts with '{}')".format(
-                proper_name, proper_name[0]
+            "Module name must start with a lowercase ASCII letter ('{}' starts with '{}'){}".format(
+                proper_name, proper_name[0], suggestion
             ),
         )
 
     if not re.fullmatch(r, proper_name):
         raise CFBSValidationError(
             name,
-            "Module name contains illegal characters (only lowercase ASCII alphanumeric characters and single dash separators are allowed)",
+            "Module name contains illegal characters (only lowercase ASCII alphanumeric characters and single dash separators are allowed)"
+            + suggestion,
         )
 
     log.debug("Successfully validated name of module %s" % name)