[IMP] base, requirements: support datamatrix barcode printing

reportlab package is already in use to print barcodes, but it requires
extra packages (pylibdmtx and libdmtx) to print Data Matrix barcodes.
Unfortunately the python3-pylibdmtx package is not currently in the
Ubuntu version being used by Odoo SaaS and odoo.sh => we cannot install
this package automatically. Therefore we leave both packages as optional
extra installs for users since pylibdmtx is available via pip3 and
additional libdmtx package can be installed at that time (libdmtx0b on
linux, other OS info in pylibdmtx pip page).

We default to Code128 to avoid blocking stacktrace in case
Reportlab cannot print Data Matrices.

Part of task: 2494740

Part-of: odoo/odoo#82389

odoo/addons/base/models/ir_actions_report.py

@@ -45,6 +45,12 @@ try:
 except Exception:
     pass
 
+datamatrix_available = True
+try:
+    from pylibdmtx import pylibdmtx
+except Exception:
+    _logger.info('A package may be missing to print Data Matrix barcodes: pylibdmtx or libdmtx.')
+    datamatrix_available = False
 
 def _get_wkhtmltopdf_bin():
     return find_in_path('wkhtmltopdf')
@@ -250,6 +256,16 @@ class IrActionsReport(models.Model):
         '''
         return wkhtmltopdf_state
 
+    @api.model
+    def datamatrix_available(self):
+        '''Returns whether or not datamatrix creation is possible.
+        * True: Reportlab seems to be able to create datamatrix without error.
+        * False: Reportlab cannot seem to create datamatrix, most likely due to missing package dependency
+
+        :return: Boolean
+        '''
+        return datamatrix_available
+
     def get_paperformat(self):
         return self.paperformat_id or self.env.company.paperformat_id
 
@@ -526,6 +542,9 @@ class IrActionsReport(models.Model):
         elif barcode_type == 'auto':
             symbology_guess = {8: 'EAN8', 13: 'EAN13'}
             barcode_type = symbology_guess.get(len(value), 'Code128')
+        elif barcode_type == 'DataMatrix' and not self.datamatrix_available():
+            # fallback to avoid stacktrack because reportlab won't recognize the type and error message isn't useful/will be blocking
+            barcode_type = 'Code128'
         try:
             width, height, humanreadable, quiet = int(width), int(height), bool(int(humanreadable)), bool(int(quiet))
             # for `QR` type, `quiet` is not supported. And is simply ignored.