From 1315b7e2b17bbb87a3dfa2c58484856b5fbaf99e Mon Sep 17 00:00:00 2001
From: yuri <164520341+yohaneYuri@users.noreply.github.com>
Date: Sat, 14 Jun 2025 00:09:21 +0800
Subject: [PATCH] Feat: inlay hint length limit (#13742)

---
 book/src/editor.md             |  1 +
 helix-term/src/commands/lsp.rs | 28 +++++++++++++++++++++++++++-
 helix-view/src/editor.rs       |  6 +++++-
 3 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/book/src/editor.md b/book/src/editor.md
index 00db71d27..667a7147c 100644
--- a/book/src/editor.md
+++ b/book/src/editor.md
@@ -157,6 +157,7 @@ The following statusline elements can be configured:
 | `display-progress-messages` | Display LSP progress messages below statusline[^1]    | `false` |
 | `auto-signature-help` | Enable automatic popup of signature help (parameter hints)  | `true`  |
 | `display-inlay-hints` | Display inlay hints[^2]                                     | `false` |
+| `inlay-hints-length-limit` | Maximum displayed length (non-zero number) of inlay hints | Unset by default  |
 | `display-color-swatches` | Show color swatches next to colors | `true` |
 | `display-signature-help-docs` | Display docs under signature help popup             | `true`  |
 | `snippets`      | Enables snippet completions. Requires a server restart (`:lsp-restart`) to take effect after `:config-reload`/`:set`. | `true`  |
diff --git a/helix-term/src/commands/lsp.rs b/helix-term/src/commands/lsp.rs
index 9c55c830c..99a6d62f9 100644
--- a/helix-term/src/commands/lsp.rs
+++ b/helix-term/src/commands/lsp.rs
@@ -1357,6 +1357,7 @@ fn compute_inlay_hints_for_view(
             let mut padding_after_inlay_hints = Vec::new();
 
             let doc_text = doc.text();
+            let inlay_hints_length_limit = doc.config.load().lsp.inlay_hints_length_limit;
 
             for hint in hints {
                 let char_idx =
@@ -1367,7 +1368,7 @@ fn compute_inlay_hints_for_view(
                         None => continue,
                     };
 
-                let label = match hint.label {
+                let mut label = match hint.label {
                     lsp::InlayHintLabel::String(s) => s,
                     lsp::InlayHintLabel::LabelParts(parts) => parts
                         .into_iter()
@@ -1375,6 +1376,31 @@ fn compute_inlay_hints_for_view(
                         .collect::<Vec<_>>()
                         .join(""),
                 };
+                // Truncate the hint if too long
+                if let Some(limit) = inlay_hints_length_limit {
+                    // Limit on displayed width
+                    use helix_core::unicode::{
+                        segmentation::UnicodeSegmentation, width::UnicodeWidthStr,
+                    };
+
+                    let width = label.width();
+                    let limit = limit.get().into();
+                    if width > limit {
+                        let mut floor_boundary = 0;
+                        let mut acc = 0;
+                        for (i, grapheme_cluster) in label.grapheme_indices(true) {
+                            acc += grapheme_cluster.width();
+
+                            if acc > limit {
+                                floor_boundary = i;
+                                break;
+                            }
+                        }
+
+                        label.truncate(floor_boundary);
+                        label.push('…');
+                    }
+                }
 
                 let inlay_hints_vec = match hint.kind {
                     Some(lsp::InlayHintKind::TYPE) => &mut type_inlay_hints,
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index bc811b88b..cb9586e79 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -29,7 +29,7 @@ use std::{
     collections::{BTreeMap, HashMap, HashSet},
     fs,
     io::{self, stdin},
-    num::NonZeroUsize,
+    num::{NonZeroU8, NonZeroUsize},
     path::{Path, PathBuf},
     pin::Pin,
     sync::Arc,
@@ -459,6 +459,9 @@ pub struct LspConfig {
     pub display_signature_help_docs: bool,
     /// Display inlay hints
     pub display_inlay_hints: bool,
+    /// Maximum displayed length of inlay hints (excluding the added trailing `…`).
+    /// If it's `None`, there's no limit
+    pub inlay_hints_length_limit: Option<NonZeroU8>,
     /// Display document color swatches
     pub display_color_swatches: bool,
     /// Whether to enable snippet support
@@ -476,6 +479,7 @@ impl Default for LspConfig {
             auto_signature_help: true,
             display_signature_help_docs: true,
             display_inlay_hints: false,
+            inlay_hints_length_limit: None,
             snippets: true,
             goto_reference_include_declaration: true,
             display_color_swatches: true,