This PR upgrades core to pydantic 2.
It involves a combination of manual changes together with automated code
mods using gritql.
Changes and known issues:
1. Current models override __repr__ to be consistent with pydantic 1
(this will be removed in a follow up PR)
Related:
https://github.com/langchain-ai/langchain/pull/25986/files#diff-e5bd296179b7a72fcd4ea5cfa28b145beaf787da057e6d122aa76ee0bb8132c9R74
2. Issue with decorator for BaseChatModel
(https://github.com/langchain-ai/langchain/pull/25986/files#diff-932bf3b314b268754ef640a5b8f52da96f9024fb81dd388dcd166b5713ecdf66R202)
-- cc @baskaryan
3. `name` attribute in Base Runnable does not have a default -- was
raising a pydantic warning due to override. We need to see if there's a
way to fix to avoid making a breaking change for folks with custom
runnables.
(https://github.com/langchain-ai/langchain/pull/25986/files#diff-836773d27f8565f4dd45e9d6cf828920f89991a880c098b7511e0d3bb78a8a0dR238)
4. Likely can remove hard-coded RunnableBranch name
(https://github.com/langchain-ai/langchain/pull/25986/files#diff-72894b94f70b1bfc908eb4d53f5ff90bb33bf8a4240a5e34cae48ddc62ac313aR147)
5. `model_*` namespace is reserved in pydantic. We'll need to specify
`protected_namespaces`
6. create_model does not have a cached path yet
7. get_input_schema() in many places has been updated to be explicit
about whether parameters are required or optional
8. injected tool args aren't picked up properly (losing type annotation)
For posterity the following gritql migrations were used:
```
engine marzano(0.1)
language python
or {
`from $IMPORT import $...` where {
$IMPORT <: contains `pydantic_v1`,
$IMPORT => `pydantic`
},
`$X.update_forward_refs` => `$X.model_rebuild`,
// This pattern still needs fixing as it fails (populate_by_name vs.
// allow_populate_by_name)
class_definition($name, $body) as $C where {
$name <: `Config`,
$body <: block($statements),
$t = "",
$statements <: some bubble($t) assignment(left=$x, right=$y) as $A where {
or {
$x <: `allow_population_by_field_name` where {
$t += `populate_by_name=$y,`
},
$t += `$x=$y,`
}
},
$C => `model_config = ConfigDict($t)`,
add_import(source="pydantic", name="ConfigDict")
}
}
```
```
engine marzano(0.1)
language python
`@root_validator(pre=True)` as $decorator where {
$decorator <: before function_definition($body, $return_type),
$decorator => `@model_validator(mode="before")\n@classmethod`,
add_import(source="pydantic", name="model_validator"),
$return_type => `Any`
}
```
```
engine marzano(0.1)
language python
`@root_validator(pre=False, skip_on_failure=True)` as $decorator where {
$decorator <: before function_definition($body, $parameters, $return_type) where {
$body <: contains bubble or {
`values["$Q"]` => `self.$Q`,
`values.get("$Q")` => `(self.$Q or None)`,
`values.get($Q, $...)` as $V where {
$Q <: contains `"$QName"`,
$V => `self.$QName`,
},
`return $Q` => `return self`
}
},
$decorator => `@model_validator(mode="after")`,
// Silly work around a bug in grit
// Adding Self to pydantic and then will replace it with one from typing
add_import(source="pydantic", name="model_validator"),
$parameters => `self`,
$return_type => `Self`
}
```
```
grit apply --language python '`Self` where { add_import(source="typing_extensions", name="Self")}'
```
Thank you for contributing to LangChain!
- [X ] **PR title**
- [X ] **PR message**:
**Description:** adds a handler for when delta choice is None
**Issue:** Fixes#25951
**Dependencies:** Not applicable
- [ X] **Add tests and docs**: Not applicable
- [X ] **Lint and test**: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified. See contribution
guidelines for more: https://python.langchain.com/docs/contributing/
Additional guidelines:
- Make sure optional dependencies are imported within a function.
- Please do not add dependencies to pyproject.toml files (even optional
ones) unless they are required for unit tests.
- Most PRs should not touch more than one package.
- Changes should be backwards compatible.
- If you are adding something to community, do not re-import it in
langchain.
If no one reviews your PR within a few days, please @-mention one of
baskaryan, efriis, eyurtsev, ccurme, vbarda, hwchase17.
Co-authored-by: Grande <Tom.Daniel.Grande@statsbygg.no>
Co-authored-by: Erick Friis <erick@langchain.dev>
**Description:**
Change the default Neo4j username/password (when not supplied as
environment variable or in code) from `None` to `""`.
Neo4j has an option to [disable
auth](https://neo4j.com/docs/operations-manual/current/configuration/configuration-settings/#config_dbms.security.auth_enabled)
which is helpful when developing. When auth is disabled, the username /
password through the `neo4j` module should be `""` (ie an empty string).
Empty strings get marked as false in
`langchain_core.utils.env.get_from_dict_or_env` -- changing this code /
behaviour would have a wide impact and is undesirable.
In order to both _allow_ access to Neo4j with auth disabled and _not_
impact `langchain_core` this patch is presented. The downside would be
that if a user forgets to set NEO4J_USERNAME or NEO4J_PASSWORD they
would see an invalid credentials error rather than missing credentials
error. This could be mitigated but would result in a less elegant patch!
**Issue:**
Fix issue where langchain cannot communicate with Neo4j if Neo4j auth is
disabled.
