Merge 97ec8494a7 into ba54b6afe4

book/src/languages.md

@@ -142,7 +142,7 @@ These are the available options for a language server.
 | `config`                   | Language server initialization options                                                                                            |
 | `timeout`                  | The maximum time a request to the language server may take, in seconds. Defaults to `20`                                          |
 | `environment`              | Any environment variables that will be used when starting the language server `{ "KEY1" = "Value1", "KEY2" = "Value2" }`          |
-| `required-root-patterns`   | A list of `glob` patterns to look for in the working directory. The language server is started if at least one of them is found.  |
+| `required-root-patterns`   | A list of `glob` patterns to look for in the working directory. The language server is started if at least one of them is found. Patterns can be negated with `!` prefix (`\\!` for escape). |
 
 A `format` sub-table within `config` can be used to pass extra formatting options to
 [Document Formatting Requests](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_formatting).

flake.nix

@@ -75,6 +75,7 @@
                 lld
                 cargo-flamegraph
                 rust-bin.nightly.latest.rust-analyzer
+                rust-bin.nightly.latest.clippy
               ]
               ++ (lib.optional (stdenv.isx86_64 && stdenv.isLinux) cargo-tarpaulin)
               ++ (lib.optional stdenv.isLinux lldb)

helix-core/src/syntax/config.rs

@@ -374,20 +374,41 @@ where
     serializer.end()
 }
 
-fn deserialize_required_root_patterns<'de, D>(deserializer: D) -> Result<Option<GlobSet>, D::Error>
+/// Deserialize required-root-patterns with globset.
+///
+/// This function returns a tuple of positive globset and negative globset.
+fn deserialize_required_root_patterns<'de, D>(
+    deserializer: D,
+) -> Result<(GlobSet, GlobSet), D::Error>
 where
     D: serde::Deserializer<'de>,
 {
     let patterns = Vec::<String>::deserialize(deserializer)?;
-    if patterns.is_empty() {
-        return Ok(None);
-    }
-    let mut builder = globset::GlobSetBuilder::new();
+
+    let mut positive_builder = globset::GlobSetBuilder::new();
+    let mut negative_builder = globset::GlobSetBuilder::new();
     for pattern in patterns {
-        let glob = globset::Glob::new(&pattern).map_err(serde::de::Error::custom)?;
-        builder.add(glob);
+        // negative pattern
+        if let Some(stripped) = pattern.strip_prefix("!") {
+            let glob = globset::Glob::new(stripped).map_err(serde::de::Error::custom)?;
+            negative_builder.add(glob);
+        }
+        // escaped pattern
+        else if let Some(_stripped) = pattern.strip_prefix("\\!") {
+            let glob = globset::Glob::new(&pattern[1..]).map_err(serde::de::Error::custom)?;
+            positive_builder.add(glob);
+        }
+        // rest is positive
+        else {
+            let glob = globset::Glob::new(&pattern).map_err(serde::de::Error::custom)?;
+            positive_builder.add(glob);
+        }
     }
-    builder.build().map(Some).map_err(serde::de::Error::custom)
+
+    let positive_globset = positive_builder.build().map_err(serde::de::Error::custom)?;
+    let negative_globset = negative_builder.build().map_err(serde::de::Error::custom)?;
+
+    Ok((positive_globset, negative_globset))
 }
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -403,12 +424,13 @@ pub struct LanguageServerConfiguration {
     pub config: Option<serde_json::Value>,
     #[serde(default = "default_timeout")]
     pub timeout: u64,
+    /// Positive and negative patterns.
     #[serde(
         default,
         skip_serializing,
         deserialize_with = "deserialize_required_root_patterns"
     )]
-    pub required_root_patterns: Option<GlobSet>,
+    pub required_root_patterns: (GlobSet, GlobSet),
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]

helix-lsp/src/lib.rs

@@ -888,16 +888,36 @@ fn start_client(
     let root_path = root.clone().unwrap_or_else(|| workspace.clone());
     let root_uri = root.and_then(|root| lsp::Url::from_file_path(root).ok());
 
-    if let Some(globset) = &ls_config.required_root_patterns {
-        if !root_path
-            .read_dir()?
-            .flatten()
-            .map(|entry| entry.file_name())
-            .any(|entry| globset.is_match(entry))
+    // match negative and positive root patterns
+    let (positive_globset, negative_globset) = &ls_config.required_root_patterns;
+    let file_names: Vec<_> = root_path
+        .read_dir()?
+        .flatten()
+        .map(|entry| entry.file_name())
+        .collect();
+    // negative
+    if !negative_globset.is_empty() {
+        if let Some(occurence) = file_names
+            .iter()
+            .find(|name| negative_globset.is_match(name))
         {
+            log::debug!(
+                "negative root pattern {} met for {}",
+                occurence.to_string_lossy(),
+                name
+            );
             return Err(StartupError::NoRequiredRootFound);
         }
     }
+    // positive
+    if !positive_globset.is_empty()
+        && !file_names
+            .iter()
+            .any(|name| positive_globset.is_match(name))
+    {
+        log::debug!("none of positive root patterns found for {}", name);
+        return Err(StartupError::NoRequiredRootFound);
+    }
 
     let (client, incoming, initialize_notify) = Client::start(
         &ls_config.command,