Merge branch 'pmderodat/preprocessing' into 'master'

Preprocessor: fix file reader when source file cannot be read

Closes #1126

See merge request eng/libadalang/libadalang!1453

extensions/src/libadalang-preprocessing.adb

@@ -131,6 +131,7 @@ package body Libadalang.Preprocessing is
       exception
          when Exc : File_Read_Error =>
             Append (Diagnostics, Exc => Exc);
+            Contents := Create_Decoded_File_Contents ("");
             return;
       end;
 
@@ -143,20 +144,17 @@ package body Libadalang.Preprocessing is
                   Diagnostics);
       Free (In_Buffer);
 
-      --  If the preprocessor returned a source buffer, decode it. If not, it
-      --  is supposed to have created diagnostics.
-
-      if Out_Buffer.Buffer = null then
-         pragma Assert (not Diagnostics.Is_Empty);
-      else
-         Decode_Buffer
-           (Out_Buffer.Buffer (1 .. Out_Buffer.Last),
-            Charset,
-            Read_BOM,
-            Contents,
-            Diagnostics);
-         Free (Out_Buffer.Buffer);
-      end if;
+      --  The preprocessor is always supposed to return a (possibly empty)
+      --  source buffer.
+
+      pragma Assert (Out_Buffer.Buffer /= null);
+      Decode_Buffer
+        (Out_Buffer.Buffer (1 .. Out_Buffer.Last),
+         Charset,
+         Read_BOM,
+         Contents,
+         Diagnostics);
+      Free (Out_Buffer.Buffer);
    end Read;
 
    -------------------

testsuite/drivers/base_driver.py

@@ -118,6 +118,12 @@ def output_refiners(self):
         if self.test_env.get("canonicalize_directory_separators", False):
             result.append(Substitute("\\", "/"))
 
+        # If requested, replace occurences of the working directory
+        if self.test_env.get("canonicalize_working_dir", False):
+            result.append(
+                Substitute(self.working_dir(), "[working-dir]")
+            )
+
         return result
 
     @property

testsuite/tests/prep/errors/bad_encoding.bin

@@ -0,0 +1 @@
+�

testsuite/tests/prep/errors/foo.adb

@@ -0,0 +1 @@
+pragma Foo ($Foo);

testsuite/tests/prep/errors/invalid.adb

@@ -0,0 +1,3 @@
+pragma Foo;
+#end if;
+pragma Bar;

testsuite/tests/prep/errors/main.adb

@@ -0,0 +1,64 @@
+with Ada.Text_IO; use Ada.Text_IO;
+
+with GPR2.Context;
+with GPR2.Path_Name;
+with GPR2.Project.Tree;
+
+with Libadalang.Analysis;      use Libadalang.Analysis;
+with Libadalang.Preprocessing; use Libadalang.Preprocessing;
+
+procedure Main is
+
+   Ctx : Analysis_Context;
+
+   procedure Process (Filename : String);
+   --  Parse the requested file and print its diagnostics and parse tree
+
+   -------------
+   -- Process --
+   -------------
+
+   procedure Process (Filename : String) is
+      U : constant Analysis_Unit :=
+        Ctx.Get_From_File (Filename, Charset => "utf-8");
+   begin
+      Put_Line ("== " & Filename & " ==");
+      New_Line;
+      if U.Has_Diagnostics then
+         for D of U.Diagnostics loop
+            Put_Line (U.Format_GNU_Diagnostic (D));
+         end loop;
+         New_Line;
+      end if;
+      U.Root.Print;
+      New_Line;
+   end Process;
+
+   --  Create a context from the example project
+
+   Tree : GPR2.Project.Tree.Object;
+begin
+   Tree.Load_Autoconf
+     (Filename => GPR2.Path_Name.Create_File
+                    ("p.gpr", GPR2.Path_Name.No_Resolution),
+      Context  => GPR2.Context.Empty);
+   Ctx := Create_Context_From_Project (Tree);
+
+   --  As a sanity check, first make sure that preprocessing is active
+
+   Process ("foo.adb");
+
+   --  Then check error cases: the source file cannot be read
+
+   Process ("no_such_file.adb");
+
+   --  Preprocessing aborts because of a syntax error
+
+   Process ("invalid.adb");
+
+   --  Buffer decoding after preprocessing fails because of an encoding error
+
+   Process ("bad_encoding.bin");
+
+   Put_Line ("Done.");
+end Main;

testsuite/tests/prep/errors/p.gpr

@@ -0,0 +1,5 @@
+project P is
+   package Compiler is
+      for Default_Switches ("Ada") use ("-gnateDfoo=null");
+   end Compiler;
+end P;

testsuite/tests/prep/errors/test.out

@@ -0,0 +1,42 @@
+== foo.adb ==
+
+PragmaNodeList[1:1-1:19]
+|  PragmaNode[1:1-1:19]
+|  |f_id:
+|  |  Id[1:8-1:11]: Foo
+|  |f_args:
+|  |  BaseAssocList[1:13-1:17]
+|  |  |  PragmaArgumentAssoc[1:13-1:17]
+|  |  |  |f_name: <null>
+|  |  |  |f_expr:
+|  |  |  |  Null[1:13-1:17]: null
+
+== no_such_file.adb ==
+
+no_such_file.adb: Cannot open [working-dir]/no_such_file.adb
+
+CompilationUnitList[1:1-1:1]: <empty list>
+
+== invalid.adb ==
+
+invalid.adb:2:2: no matching "#if"
+
+PragmaNodeList[1:1-3:12]
+|  PragmaNode[1:1-1:12]
+|  |f_id:
+|  |  Id[1:8-1:11]: Foo
+|  |f_args:
+|  |  BaseAssocList[1:7-1:7]: <empty list>
+|  PragmaNode[3:1-3:12]
+|  |f_id:
+|  |  Id[3:8-3:11]: Bar
+|  |f_args:
+|  |  BaseAssocList[3:7-3:7]: <empty list>
+
+== bad_encoding.bin ==
+
+bad_encoding.bin:1:1: Could not decode source as "utf-8"
+
+CompilationUnitList[1:1-1:1]: <empty list>
+
+Done.

testsuite/tests/prep/errors/test.yaml

@@ -0,0 +1,5 @@
+driver: ada-api
+main: main.adb
+canonicalize_working_dir: true
+control:
+    - [XFAIL, "valgrind", "Pending resolution of eng/gpr/gpr-issues#43"]