(camel) branch main updated: CAMEL-23608: camel-jbang - avoid JLine for terminal width detection

[davsclaus]

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davsclaus pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/camel.git


The following commit(s) were added to refs/heads/main by this push:
     new 2392a963cc04 CAMEL-23608: camel-jbang - avoid JLine for terminal width 
detection
2392a963cc04 is described below

commit 2392a963cc040beea5ab68f835b3fd736e2b4a81
Author: Claus Ibsen <claus.ib...@gmail.com>
AuthorDate: Tue May 26 07:13:53 2026 +0200

    CAMEL-23608: camel-jbang - avoid JLine for terminal width detection
    
    Replace JLine TerminalBuilder with COLUMNS env var / stty size for
    terminal width detection in TerminalWidthHelper. JLine sends DA1 and
    CPR escape sequence queries when creating a system terminal, and the
    responses can leak into shell output after commands like camel ps.
    
    The new approach uses COLUMNS env var (set by most shells) with stty
    size as fallback, avoiding escape sequences entirely. Falls back to
    120 columns if neither is available.
    
    Closes #23510
---
 .../dsl/jbang/core/common/TerminalWidthHelper.java | 51 +++++++++++++++-------
 1 file changed, 36 insertions(+), 15 deletions(-)

diff --git 
a/dsl/camel-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/common/TerminalWidthHelper.java
 
b/dsl/camel-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/common/TerminalWidthHelper.java
index dd723f38390e..e096f8f96150 100644
--- 
a/dsl/camel-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/common/TerminalWidthHelper.java
+++ 
b/dsl/camel-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/common/TerminalWidthHelper.java
@@ -16,15 +16,16 @@
  */
 package org.apache.camel.dsl.jbang.core.common;
 
-import org.jline.terminal.Terminal;
-import org.jline.terminal.TerminalBuilder;
-
 /**
  * Helper for detecting the terminal width to adapt table and command output.
  *
  * <p>
- * Uses JLine to query the actual terminal size. Falls back to a default width 
when the terminal size cannot be
- * determined (e.g., when output is piped or redirected).
+ * Uses the {@code COLUMNS} environment variable or {@code stty size} to 
detect the terminal width. Falls back to a
+ * default width when the terminal size cannot be determined (e.g., when 
output is piped or redirected).
+ *
+ * <p>
+ * Avoids using JLine's {@code TerminalBuilder} for width detection because it 
sends escape sequence queries (DA1, CPR)
+ * to the terminal that can leak into the shell output when the terminal is 
closed before responses arrive.
  */
 public final class TerminalWidthHelper {
 
@@ -38,20 +39,40 @@ public final class TerminalWidthHelper {
      * Returns the current terminal width in columns.
      *
      * <p>
-     * Attempts to detect the terminal width using JLine. Returns {@value 
#DEFAULT_WIDTH} if detection fails or if the
-     * output is not connected to a terminal.
+     * Tries {@code COLUMNS} environment variable first, then {@code stty 
size}. Returns {@value #DEFAULT_WIDTH} if
+     * detection fails or if the output is not connected to a terminal.
      */
     public static int getTerminalWidth() {
-        try (Terminal terminal = TerminalBuilder.builder()
-                .system(true)
-                .dumb(true)
-                .build()) {
-            int width = terminal.getWidth();
-            if (width > 0) {
-                return Math.max(width, MIN_WIDTH);
+        // Try COLUMNS env var first (set by most shells)
+        String cols = System.getenv("COLUMNS");
+        if (cols != null) {
+            try {
+                int w = Integer.parseInt(cols.trim());
+                if (w > 0) {
+                    return Math.max(w, MIN_WIDTH);
+                }
+            } catch (NumberFormatException e) {
+                // ignore
+            }
+        }
+        // Fall back to stty which reads the terminal size without escape 
sequences
+        try {
+            Process p = new ProcessBuilder("stty", "size")
+                    .redirectInput(ProcessBuilder.Redirect.INHERIT)
+                    .start();
+            String output = new 
String(p.getInputStream().readAllBytes()).trim();
+            p.waitFor();
+            if (!output.isEmpty()) {
+                String[] parts = output.split("\\s+");
+                if (parts.length >= 2) {
+                    int w = Integer.parseInt(parts[1]);
+                    if (w > 0) {
+                        return Math.max(w, MIN_WIDTH);
+                    }
+                }
             }
         } catch (Exception e) {
-            // ignore
+            // ignore — stty not available (e.g. Windows)
         }
         return DEFAULT_WIDTH;
     }