FIXUP: redirect stderr when debug=True or sys.dangerzone_dev == True

dangerzone/isolation_provider/base.py

@@ -55,14 +55,17 @@ class IsolationProvider(ABC):
 
     def __init__(self, debug) -> None:
         self.debug = debug
-        if self.debug:
+        if self.should_display_errors():
             self.proc_stderr = subprocess.PIPE
         else:
             # We do not trust STDERR from the inner container,
             # which could be exploited to ask users to open the document with
             # a default PDF reader for instance.
             self.proc_stderr = subprocess.DEVNULL
 
+    def should_display_errors(self) -> bool:
+        return self.debug or getattr(sys, "dangerzone_dev", False)
+
     @abstractmethod
     def install(self) -> bool:
         pass
@@ -146,7 +149,7 @@ def doc_to_pixels(
         text = "Converted document to pixels"
         self.print_progress(document, False, text, percentage)
 
-        if self.debug:
+        if self.should_display_errors():
             assert p.stderr
             debug_log = read_debug_text(p.stderr, MAX_CONVERSION_LOG_CHARS)
             p.stderr.close()