port: Show error when Gtk typelib is missing

Fixes #72 by showing a proper error message rather than crashing.

blueprintcompiler/errors.py

@@ -80,14 +80,16 @@ class CompileError(PrintableError):
             self.hint("Are your dependencies up to date?")
 
     def pretty_print(self, filename, code, stream=sys.stdout):
-        line_num, col_num = utils.idx_to_pos(self.start + 1, code)
-        line = code.splitlines(True)[line_num]
+        stream.write(f"""{self.color}{Colors.BOLD}{self.category}: {self.message}{Colors.CLEAR}\n""")
 
-        # Display 1-based line numbers
-        line_num += 1
+        if code is not None and self.start is not None:
+            line_num, col_num = utils.idx_to_pos(self.start + 1, code)
+            line = code.splitlines(True)[line_num]
 
-        stream.write(f"""{self.color}{Colors.BOLD}{self.category}: {self.message}{Colors.CLEAR}
-at {filename} line {line_num} column {col_num}:
+            # Display 1-based line numbers
+            line_num += 1
+
+            stream.write(f"""at {filename} line {line_num} column {col_num}:
 {Colors.FAINT}{line_num :>4} |{Colors.CLEAR}{line.rstrip()}\n     {Colors.FAINT}|{" "*(col_num-1)}^{Colors.CLEAR}\n""")
 
         for hint in self.hints:
@@ -115,6 +117,15 @@ class UnexpectedTokenError(CompileError):
         super().__init__("Unexpected tokens", start, end)
 
 
+class GtkTypelibMissingError(CompileError):
+    def __init__(self, **kwargs):
+        super().__init__(
+            "Could not find GTK 4 introspection files. Is gobject-introspection installed?",
+            fatal=True,
+            **kwargs
+        )
+
+
 @dataclass
 class CodeAction:
     title: str

blueprintcompiler/gir.py

@@ -25,7 +25,7 @@ import gi # type: ignore
 gi.require_version("GIRepository", "2.0")
 from gi.repository import GIRepository # type: ignore
 
-from .errors import CompileError, CompilerBugError
+from .errors import CompileError, CompilerBugError, GtkTypelibMissingError
 from . import typelib, xml_reader
 
 _namespace_cache = {}
@@ -49,10 +49,15 @@ def get_namespace(namespace, version):
                 break
 
         if filename not in _namespace_cache:
-            raise CompileError(
-                f"Namespace {namespace}-{version} could not be found",
-                hints=["search path: " + os.pathsep.join(search_paths)],
-            )
+            hints = ["search path: " + os.pathsep.join(search_paths)]
+
+            if namespace == "Gtk":
+                raise GtkTypelibMissingError(hints=hints)
+            else:
+                raise CompileError(
+                    f"Namespace {namespace}-{version} could not be found",
+                    hints=hints,
+                )
 
     return _namespace_cache[filename]
 

blueprintcompiler/interactive_port.py

@@ -23,7 +23,7 @@ import difflib
 import os
 
 from . import decompiler, tokenizer, parser
-from .errors import MultipleErrors, PrintableError
+from .errors import MultipleErrors, PrintableError, GtkTypelibMissingError
 from .utils import Colors
 
 
@@ -156,11 +156,15 @@ def step2():
 def step3():
     print(f"{Colors.BOLD}STEP 3: Convert UI files{Colors.CLEAR}")
 
-    files = [
-        (file, change_suffix(file), decompile_file(file, change_suffix(file)))
-        for file in listdir_recursive(".")
-        if file.endswith(".ui")
-    ]
+    try:
+        files = [
+            (file, change_suffix(file), decompile_file(file, change_suffix(file)))
+            for file in listdir_recursive(".")
+            if file.endswith(".ui")
+        ]
+    except GtkTypelibMissingError as e:
+        e.pretty_print(None, None)
+        return ([], [])
 
     success = 0
     for in_file, out_file, result in files:

blueprintcompiler/language/imports.py

@@ -40,17 +40,7 @@ class GtkDirective(AstNode):
                 err.hint("Expected 'using Gtk 4.0;'")
             raise err
 
-        try:
-            gir.get_namespace("Gtk", version)
-        except CompileError as e:
-            raise CompileError(
-                "Could not find GTK 4 introspection files. Is gobject-introspection installed?",
-                fatal=True,
-                # preserve the hints from the original error, because it contains
-                # useful debugging information
-                hints=e.hints,
-            )
-
+        gir.get_namespace("Gtk", version)
 
     @property
     def gir_namespace(self):