From 81f1ec1d0b48bb2329a0c781991a7169b4f6b3c8 Mon Sep 17 00:00:00 2001
From: Tristan Gingold <tgingold@free.fr>
Date: Sun, 27 Nov 2022 16:05:05 +0100
Subject: file_comments: fix handling of comment on the same line.

---
 src/file_comments.adb | 68 ++++++++++++++++++++++++++++++++++++---------------
 src/file_comments.ads |  8 ++++--
 2 files changed, 54 insertions(+), 22 deletions(-)

diff --git a/src/file_comments.adb b/src/file_comments.adb
index 8e747f748..246a7ad7b 100644
--- a/src/file_comments.adb
+++ b/src/file_comments.adb
@@ -72,6 +72,23 @@ package body File_Comments is
       Ctxt.Next := Last + 1;
    end Comment_Gather_Existing;
 
+   function Is_Empty_Line (Line_Start : Source_Ptr) return Boolean
+   is
+      Fc : File_Comments_Table renames
+        Comments_Table.Table (Ctxt.File);
+      Last : constant Comment_Index := File_Comments_Tables.Last (Fc);
+   begin
+      --  The start of the line is after the last comment, so the line is
+      --  empty.
+      return Line_Start > Fc.Table (Last).Last;
+   end Is_Empty_Line;
+
+   --  Very important: this procedure is called only after a comment has
+   --  been scanned and added.
+   --  So this is either the newline after a comment (in that case
+   --   LINE_START is less than the last comment),
+   --  or an empty line (in that case LINE_START is greater than the last
+   --   comment).
    procedure Comment_Newline (Line_Start : Source_Ptr) is
    begin
       case Ctxt.State is
@@ -80,21 +97,22 @@ package body File_Comments is
          when State_Block =>
             --  Detect empty line.
             --  This can happen only after a comments has been added.
-            declare
-               Fc : File_Comments_Table renames
-                 Comments_Table.Table (Ctxt.File);
-               Last : constant Comment_Index := File_Comments_Tables.Last (Fc);
-            begin
-               if Line_Start > Fc.Table (Last).Last then
-                  --  Newline without a comment.
-                  --  Attach existing comments.
-                  Comment_Gather_Existing;
-               end if;
-            end;
+            if Is_Empty_Line (Line_Start) then
+               --  Attach existing comments.
+               Comment_Gather_Existing;
+            end if;
          when State_Line =>
-            --  No comment on the same line.
+            --  If a comment appear before the newline, the state would be
+            --  changed to State_Line_Cont; so here no comment on the same
+            --  line.
+            --
             --  The following comments will be attached to the next node.
             Ctxt.State := State_Before;
+         when State_Line_Cont =>
+            --  If the line is empty, change to State_Block.
+            if Is_Empty_Line (Line_Start) then
+               Ctxt.State := State_Block;
+            end if;
       end case;
    end Comment_Newline;
 
@@ -132,24 +150,32 @@ package body File_Comments is
             end if;
          when State_Line =>
             --  Is it on the same line ?
+            if Flag_Trace then
+               Put ("line");
+               Put (" (start=");
+               Put_Uns32 (Uns32 (Ctxt.Line_Start));
+               Put (", cmt=");
+               Put_Uns32 (Uns32 (Line_Start));
+               Put (")");
+            end if;
             if Line_Start = Ctxt.Line_Start then
                N := Ctxt.Last_Node;
                Ctxt.Next := File_Comments_Tables.Last
                  (Comments_Table.Table (Ctxt.File)) + 2;
-               Ctxt.State := State_Block;
+               Ctxt.State := State_Line_Cont;
             else
                --  Not the same line, for the next node.
                N := 0;
                Ctxt.State := State_Before;
             end if;
+         when State_Line_Cont =>
+            --  Attached on the next empty line.
             if Flag_Trace then
-               Put ("line");
-               Put (" (start=");
-               Put_Uns32 (Uns32 (Ctxt.Line_Start));
-               Put (", cmt=");
-               Put_Uns32 (Uns32 (Line_Start));
-               Put (")");
+               Put ("line_cont");
             end if;
+            N := Ctxt.Last_Node;
+            Ctxt.Next := File_Comments_Tables.Last
+              (Comments_Table.Table (Ctxt.File)) + 2;
       end case;
 
       if Flag_Trace then
@@ -240,7 +266,9 @@ package body File_Comments is
             end;
          when State_Block =>
             Comment_Gather_Existing;
-         when State_Line =>
+         when State_Line
+           | State_Line_Cont =>
+            --  All comments are attached.
             null;
       end case;
       Ctxt.State := State_Before;
diff --git a/src/file_comments.ads b/src/file_comments.ads
index 0afc4fcbd..0869ed31b 100644
--- a/src/file_comments.ads
+++ b/src/file_comments.ads
@@ -35,7 +35,7 @@ package File_Comments is
    procedure Add_Comment (Start, Last : Source_Ptr;
                           Line_Start : Source_Ptr);
 
-   --  A newline (after a comment) has been scanned.
+   --  A newline *after a comment* has been scanned.
    --  If this is a blank line, comments before the blank line are attached
    --  to the previous node.
    procedure Comment_Newline (Line_Start : Source_Ptr);
@@ -117,7 +117,11 @@ private
 
       --  If the next comment is on the same line, it will be attached to
       --  LAST_NODE, and so will be the next comments.
-      State_Line
+      State_Line,
+
+      --  Continuation of line.  Any comment is attached to the LAST_NODE,
+      --  until an empty line.
+      State_Line_Cont
      );
 
    type Comment_Context is record
-- 
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