Auto-resolve .dsm extension in DSM #include directives (#286)

When a #include path doesn't exist as-is, automatically try
appending ".dsm" before failing. This fixes the common case where
DSM scripts use #include without the file extension (e.g.
#include "ivr_apps" instead of #include "ivr_apps.dsm").

Replaces the previous hint-only diagnostic with an actual fallback
that resolves the path transparently.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

apps/dsm/DSMStateDiagramCollection.cpp

@@ -47,14 +47,6 @@ bool DSMStateDiagramCollection::readFile(const string& filename, const string& n
   if (!ifs.good()) {
     ERROR("loading state diagram '%s': cannot open file (%s)\n",
 	  filename.c_str(), strerror(errno));
-
-    // Check if the user forgot the .dsm extension (common #include mistake)
-    string with_ext = filename + ".dsm";
-    ifstream test_ifs(with_ext.c_str());
-    if (test_ifs.good()) {
-      ERROR("  Hint: '%s' exists - did you mean to use '%s' in your #include directive?\n",
-	    with_ext.c_str(), with_ext.c_str());
-    }
     return false;
   }
 
@@ -113,7 +105,18 @@ bool DSMStateDiagramCollection::readFile(const string& filename, const string& n
 	    return false;
 	  }
 	} else {
-	  if (!readFile(include_name, name, current_load_path, s)) {
+	  // If path doesn't exist, try appending .dsm extension as fallback
+	  string actual_include = include_name;
+	  if (stat(include_name.c_str(), &status) != 0) {
+	    string with_ext = include_name + ".dsm";
+	    if (stat(with_ext.c_str(), &status) == 0 &&
+		!(status.st_mode & S_IFDIR)) {
+	      DBG("'%s' not found, using '%s'\n",
+		  include_name.c_str(), with_ext.c_str());
+	      actual_include = with_ext;
+	    }
+	  }
+	  if (!readFile(actual_include, name, current_load_path, s)) {
 	    ERROR("  while processing '#include %s' in '%s'\n",
 		  include_name.c_str(), filename.c_str());
 	    return false;

doc/dsm/Readme.dsm.txt

@@ -62,9 +62,12 @@ A patch for fmsc 1.0.4 from the graphical FSM editor fsme
 click-n-drag fashion and compiled to SEMS DSM diagrams.
 
 DSM scripts can include other scripts by using the #include "script.dsm"
-directive. That loads a script from the load path (where the current 
-script resides), unless an absolute path is given (e.g. 
-#include "/path/to/script).
+directive. That loads a script from the load path (where the current
+script resides), unless an absolute path is given (e.g.
+#include "/path/to/script"). The .dsm extension is optional:
+#include "script" will automatically resolve to "script.dsm" if the
+bare path does not exist. If the path refers to a directory, all .dsm
+files in that directory are included.
 
 There is SIP Session Timer (RFC4028) support, which is configured in 
 dsm.conf. By default, session timers are turned not enabled.

doc/dsm/dsm_syntax.txt

@@ -7,10 +7,16 @@ Syntax
 # comment, too
 
 #include "script.dsm"
+#include "script"
 #include "script_dir"
 #include "/path/to/anotherscript.dsm"
+#include "/path/to/anotherscript"
 #include "/path/to/script_dir"
 
+The .dsm extension is optional in #include directives: if the path does
+not exist as-is and appending ".dsm" matches a file, it is used
+automatically. Directory includes load all .dsm files from the directory.
+
 import(mod_name);
 
 [initial] state name