move cloning into Coder.create, summarize chat history if edit format changes

aider/coders/base_coder.py

@@ -66,6 +66,7 @@ class Coder:
         main_model=None,
         edit_format=None,
         io=None,
+        from_coder=None,
         **kwargs,
     ):
         from . import EditBlockCoder, UnifiedDiffCoder, WholeFileCoder
@@ -76,15 +77,42 @@ class Coder:
         if edit_format is None:
             edit_format = main_model.edit_format
 
+        if from_coder:
+            use_kwargs = dict(from_coder.original_kwargs)  # copy orig kwargs
+
+            # If the edit format changes, we can't leave old ASSISTANT
+            # messages in the chat history. The old edit format will
+            # confused the new LLM. It may try and imitate it, disobeying
+            # the system prompt.
+            done_messages = from_coder.done_messages
+            if edit_format != from_coder.edit_format and done_messages:
+                done_messages = from_coder.summarizer.summarize_all(done_messages)
+
+            # Bring along context from the old Coder
+            update = dict(
+                fnames=from_coder.get_inchat_relative_files(),
+                done_messages=done_messages,
+                cur_messages=from_coder.cur_messages,
+            )
+
+            use_kwargs.update(update)  # override to complete the switch
+            use_kwargs.update(kwargs)  # override passed kwargs
+
+            kwargs = use_kwargs
+
         if edit_format == "diff":
-            return EditBlockCoder(main_model, io, **kwargs)
+            res = EditBlockCoder(main_model, io, **kwargs)
         elif edit_format == "whole":
-            return WholeFileCoder(main_model, io, **kwargs)
+            res = WholeFileCoder(main_model, io, **kwargs)
         elif edit_format == "udiff":
-            return UnifiedDiffCoder(main_model, io, **kwargs)
+            res = UnifiedDiffCoder(main_model, io, **kwargs)
         else:
             raise ValueError(f"Unknown edit format {edit_format}")
 
+        res.original_kwargs = dict(kwargs)
+
+        return res
+
     def get_announcements(self):
         lines = []
         lines.append(f"Aider v{__version__}")

aider/coders/wholefile_prompts.py

@@ -18,14 +18,14 @@ Once you understand the request you MUST:
 You MUST use this *file listing* format:
 
 path/to/filename.js
-{fence[0]}javascript
+{fence[0]}
 // entire file content ...
 // ... goes in between
 {fence[1]}
 
 Every *file listing* MUST use this format:
 - First line: the filename with any originally provided path
-- Second line: opening {fence[0]} including the code language
+- Second line: opening {fence[0]}
 - ... entire content of the file ...
 - Final line: closing {fence[1]}
 

aider/main.py

@@ -306,30 +306,28 @@ def main(argv=None, input=None, output=None, force_git_root=None, return_coder=F
     if args.show_model_warnings:
         models.sanity_check_models(io, main_model)
 
-    coder_kwargs = dict(
-        main_model=main_model,
-        edit_format=args.edit_format,
-        io=io,
-        ##
-        fnames=fnames,
-        git_dname=git_dname,
-        pretty=args.pretty,
-        show_diffs=args.show_diffs,
-        auto_commits=args.auto_commits,
-        dirty_commits=args.dirty_commits,
-        dry_run=args.dry_run,
-        map_tokens=args.map_tokens,
-        verbose=args.verbose,
-        assistant_output_color=args.assistant_output_color,
-        code_theme=args.code_theme,
-        stream=args.stream,
-        use_git=args.git,
-        voice_language=args.voice_language,
-        aider_ignore_file=args.aiderignore,
-    )
-
     try:
-        coder = Coder.create(**coder_kwargs)
+        coder = Coder.create(
+            main_model=main_model,
+            edit_format=args.edit_format,
+            io=io,
+            ##
+            fnames=fnames,
+            git_dname=git_dname,
+            pretty=args.pretty,
+            show_diffs=args.show_diffs,
+            auto_commits=args.auto_commits,
+            dirty_commits=args.dirty_commits,
+            dry_run=args.dry_run,
+            map_tokens=args.map_tokens,
+            verbose=args.verbose,
+            assistant_output_color=args.assistant_output_color,
+            code_theme=args.code_theme,
+            stream=args.stream,
+            use_git=args.git,
+            voice_language=args.voice_language,
+            aider_ignore_file=args.aiderignore,
+        )
 
     except ValueError as err:
         io.tool_error(str(err))
@@ -397,16 +395,7 @@ def main(argv=None, input=None, output=None, force_git_root=None, return_coder=F
             coder.run()
             return
         except SwitchModel as switch:
-            kwargs = dict(
+            coder = Coder.create(main_model=switch.model, io=io, from_coder=coder)
-                main_model=switch.model,
-                edit_format=None,
-                fnames=coder.get_inchat_relative_files(),
-                done_messages=coder.done_messages,
-                cur_messages=coder.cur_messages,
-            )
-            coder_kwargs.update(kwargs)
-
-            coder = Coder.create(**coder_kwargs)
             coder.show_announcements()