templates,docs: leave templates in v0.2 (langchain-ai#27952)

all template installs will now have to declare `--branch v0.2` to make
clear they aren't compatible with langchain 0.3 (most have a pydantic v1
setup). e.g.

```
langchain-cli app add pirate-speak --branch v0.2
```

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,7 +1,7 @@
 Thank you for contributing to LangChain!
 
 - [ ] **PR title**: "package: description"
-  - Where "package" is whichever of langchain, community, core, etc. is being modified. Use "docs: ..." for purely docs changes, "templates: ..." for template changes, "infra: ..." for CI changes.
+  - Where "package" is whichever of langchain, community, core, etc. is being modified. Use "docs: ..." for purely docs changes, "infra: ..." for CI changes.
   - Example: "community: add foobar LLM"
 
 

.github/scripts/check_diff.py

@@ -307,7 +307,7 @@ def _get_configs_for_multi_dirs(
                 f"Unknown lib: {file}. check_diff.py likely needs "
                 "an update for this new library!"
             )
-        elif any(file.startswith(p) for p in ["docs/", "templates/", "cookbook/"]):
+        elif any(file.startswith(p) for p in ["docs/", "cookbook/"]):
             if file.startswith("docs/"):
                 docs_edited = True
             dirs_to_run["lint"].add(".")

Makefile

@@ -66,12 +66,12 @@ spell_fix:
 
 ## lint: Run linting on the project.
 lint lint_package lint_tests:
-	poetry run ruff check docs templates cookbook
-	poetry run ruff format docs templates cookbook --diff
-	poetry run ruff check --select I docs templates cookbook
-	git grep 'from langchain import' docs/docs templates cookbook | grep -vE 'from langchain import (hub)' && exit 1 || exit 0
+	poetry run ruff check docs cookbook
+	poetry run ruff format docs cookbook cookbook --diff
+	poetry run ruff check --select I docs cookbook
+	git grep 'from langchain import' docs/docs cookbook | grep -vE 'from langchain import (hub)' && exit 1 || exit 0
 
 ## format: Format the project files.
 format format_diff:
-	poetry run ruff format docs templates cookbook
-	poetry run ruff check --select I --fix docs templates cookbook
+	poetry run ruff format docs cookbook
+	poetry run ruff check --select I --fix docs cookbook

docs/scripts/arxiv_references.py

@@ -406,7 +406,9 @@ def _format_api_ref_url(doc_path: str, compact: bool = False) -> str:
 
 
 def _format_template_url(template_name: str) -> str:
-    return f"https://{LANGCHAIN_PYTHON_URL}/docs/templates/{template_name}"
+    return (
+        f"https://github.com/langchain-ai/langchain/blob/v0.2/templates/{template_name}"
+    )
 
 
 def _format_cookbook_url(cookbook_name: str) -> str:

docs/vercel.json

@@ -76,7 +76,7 @@
     },
     {
       "source": "/v0.2/docs/templates/:path(.*/?)*",
-      "destination": "https://github.com/langchain-ai/langchain/tree/master/templates/:path*"
+      "destination": "https://github.com/langchain-ai/langchain/tree/v0.2/templates/:path*"
     },
     {
       "source": "/docs/integrations/providers/mlflow_ai_gateway(/?)",

libs/cli/README.md

@@ -4,5 +4,3 @@ This package implements the official CLI for LangChain. Right now, it is most us
 for getting started with LangChain Templates!
 
 [CLI Docs](https://github.com/langchain-ai/langchain/blob/master/libs/cli/DOCS.md)
-
-[LangServe Templates Quickstart](https://github.com/langchain-ai/langchain/blob/master/templates/README.md)