From b85180fedb410a90ce0af2fd88d44de35d81c249 Mon Sep 17 00:00:00 2001
From: Louis Dureuil <louis@meilisearch.com>
Date: Mon, 24 Feb 2025 13:55:40 +0100
Subject: [PATCH] Error types

---
 crates/meilisearch-types/src/error.rs |  7 +--
 crates/milli/src/error.rs             | 64 ++++++++++++++++++++-------
 2 files changed, 53 insertions(+), 18 deletions(-)

diff --git a/crates/meilisearch-types/src/error.rs b/crates/meilisearch-types/src/error.rs
index f64301b8c..5a0451b6c 100644
--- a/crates/meilisearch-types/src/error.rs
+++ b/crates/meilisearch-types/src/error.rs
@@ -428,9 +428,10 @@ impl ErrorCode for milli::Error {
                     | UserError::InvalidUrl { .. }
                     | UserError::InvalidSettingsDocumentTemplateMaxBytes { .. }
                     | UserError::InvalidPrompt(_)
-                    | UserError::InvalidDisableBinaryQuantization { .. } => {
-                        Code::InvalidSettingsEmbedders
-                    }
+                    | UserError::InvalidDisableBinaryQuantization { .. }
+                    | UserError::InvalidSourceForNested { .. }
+                    | UserError::MissingSourceForNested { .. }
+                    | UserError::InvalidSettingsEmbedder { .. } => Code::InvalidSettingsEmbedders,
                     UserError::TooManyEmbedders(_) => Code::InvalidSettingsEmbedders,
                     UserError::InvalidPromptForEmbeddings(..) => Code::InvalidSettingsEmbedders,
                     UserError::NoPrimaryKeyCandidateFound => Code::IndexPrimaryKeyNoCandidateFound,
diff --git a/crates/milli/src/error.rs b/crates/milli/src/error.rs
index c8ed1912f..c977362d6 100644
--- a/crates/milli/src/error.rs
+++ b/crates/milli/src/error.rs
@@ -13,6 +13,7 @@ use thiserror::Error;
 use crate::constants::RESERVED_GEO_FIELD_NAME;
 use crate::documents::{self, DocumentsBatchCursorError};
 use crate::thread_pool_no_abort::PanicCatched;
+use crate::vector::settings::EmbeddingSettings;
 use crate::{CriterionError, DocumentId, FieldId, Object, SortError};
 
 pub fn is_reserved_keyword(keyword: &str) -> bool {
@@ -229,28 +230,52 @@ and can not be more than 511 bytes.", .document_id.to_string()
     InvalidSimilarEmbedder(String),
     #[error("Too many vectors for document with id {0}: found {1}, but limited to 256.")]
     TooManyVectors(String, usize),
-    #[error("`.embedders.{embedder_name}`: Field `{field}` unavailable for source `{source_}` (only available for sources: {}). Available fields: {}",
-        allowed_sources_for_field
-         .iter()
-         .map(|accepted| format!("`{}`", accepted))
-         .collect::<Vec<String>>()
-         .join(", "),
-        allowed_fields_for_source
-         .iter()
-         .map(|accepted| format!("`{}`", accepted))
-         .collect::<Vec<String>>()
-         .join(", ")
+    #[error("`.embedders.{embedder_name}`: Field `{field}` unavailable for source `{source_}`{for_context}.{available_sources}{available_fields}{available_contexts}",
+    field=field.name(),
+        for_context={
+            context.in_context()
+        },
+        available_sources={
+            let allowed_sources_for_field = EmbeddingSettings::allowed_sources_for_field(*field, *context);
+            if allowed_sources_for_field.is_empty() {
+                String::new()
+            } else {
+                format!("\n  - note: `{}` is available for sources: {}",
+                field.name(),
+                allowed_sources_for_field
+                .iter()
+                .map(|accepted| format!("`{}`", accepted))
+                .collect::<Vec<String>>()
+                .join(", "),
+            )
+            }
+        },
+        available_fields={
+            let allowed_fields_for_source = EmbeddingSettings::allowed_fields_for_source(*source_, *context);
+            format!("\n  - note: available fields for source `{source_}`{}: {}",context.in_context(), allowed_fields_for_source
+            .iter()
+            .map(|accepted| format!("`{}`", accepted))
+            .collect::<Vec<String>>()
+            .join(", "),)
+        },
+        available_contexts={
+            let available_not_nested = !matches!(EmbeddingSettings::field_status(*source_, *field, crate::vector::settings::NestingContext::NotNested), crate::vector::settings::FieldStatus::Disallowed);
+            if available_not_nested {
+                format!("\n  - note: `{}` is available when source `{source_}` is not{}", field.name(), context.in_context())
+            } else {
+                String::new()
+            }
+        }
     )]
     InvalidFieldForSource {
         embedder_name: String,
         source_: crate::vector::settings::EmbedderSource,
-        field: &'static str,
-        allowed_fields_for_source: &'static [&'static str],
-        allowed_sources_for_field: &'static [crate::vector::settings::EmbedderSource],
+        context: crate::vector::settings::NestingContext,
+        field: crate::vector::settings::MetaEmbeddingSetting,
     },
     #[error("`.embedders.{embedder_name}.model`: Invalid model `{model}` for OpenAI. Supported models: {:?}", crate::vector::openai::EmbeddingModel::supported_models())]
     InvalidOpenAiModel { embedder_name: String, model: String },
-    #[error("`.embedders.{embedder_name}`: Missing field `{field}` (note: this field is mandatory for source {source_})")]
+    #[error("`.embedders.{embedder_name}`: Missing field `{field}` (note: this field is mandatory for source `{source_}`)")]
     MissingFieldForSource {
         field: &'static str,
         source_: crate::vector::settings::EmbedderSource,
@@ -270,6 +295,15 @@ and can not be more than 511 bytes.", .document_id.to_string()
         dimensions: usize,
         max_dimensions: usize,
     },
+    #[error("`.embedders.{embedder_name}.source`: Source `{source_}` is not available in a nested embedder")]
+    InvalidSourceForNested {
+        embedder_name: String,
+        source_: crate::vector::settings::EmbedderSource,
+    },
+    #[error("`.embedders.{embedder_name}`: Missing field `source`.\n  - note: this field is mandatory for nested embedders")]
+    MissingSourceForNested { embedder_name: String },
+    #[error("`.embedders.{embedder_name}`: {message}")]
+    InvalidSettingsEmbedder { embedder_name: String, message: String },
     #[error("`.embedders.{embedder_name}.dimensions`: `dimensions` cannot be zero")]
     InvalidSettingsDimensions { embedder_name: String },
     #[error(