From ec4b06c440bf72ca143d5bb8fb08fde264d3fe33 Mon Sep 17 00:00:00 2001
From: Markus KARG <markus@headcrashing.eu>
Date: Thu, 14 Dec 2023 15:54:06 +0000
Subject: [PATCH] Fixes #557: Now validates BEFORE conversion

---
 .../java/com/beust/jcommander/JCommander.java | 12 ++++++-----
 .../com/beust/jcommander/JCommanderTest.java  | 21 +++++++++++++++++++
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/beust/jcommander/JCommander.java b/src/main/java/com/beust/jcommander/JCommander.java
index b257e7ef..d2d47284 100644
--- a/src/main/java/com/beust/jcommander/JCommander.java
+++ b/src/main/java/com/beust/jcommander/JCommander.java
@@ -795,6 +795,13 @@ else if (commands.isEmpty()) {
                     //
                     initMainParameterValue(arg);
                     String value = a; // If there's a non-quoted version, prefer that one
+
+                    for(final Class<? extends IParameterValidator> validator : mainParameter.annotation.validateWith()
+                            ) {
+                        mainParameter.description.validateParameter(validator,
+                            "Default", value);
+                    }
+
                     Object convertedValue = value;
 
                     // Fix
@@ -813,11 +820,6 @@ else if (commands.isEmpty()) {
                         }
                     }
 
-                    for(final Class<? extends IParameterValidator> validator : mainParameter.annotation.validateWith()
-                            ) {
-                        mainParameter.description.validateParameter(validator,
-                            "Default", value);
-                    }
 
                     mainParameter.description.setAssigned(true);
                     mainParameter.addValue(convertedValue);
diff --git a/src/test/java/com/beust/jcommander/JCommanderTest.java b/src/test/java/com/beust/jcommander/JCommanderTest.java
index 0edfccc5..f8827774 100644
--- a/src/test/java/com/beust/jcommander/JCommanderTest.java
+++ b/src/test/java/com/beust/jcommander/JCommanderTest.java
@@ -25,6 +25,7 @@
 import com.beust.jcommander.command.CommandMain;
 import com.beust.jcommander.converters.EnumConverter;
 import com.beust.jcommander.converters.FileConverter;
+import com.beust.jcommander.converters.PathConverter;
 import com.beust.jcommander.internal.Lists;
 import com.beust.jcommander.internal.Maps;
 import org.testng.Assert;
@@ -34,6 +35,7 @@
 import java.io.*;
 import java.math.BigDecimal;
 import java.nio.charset.Charset;
+import java.nio.file.Path;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.*;
@@ -822,6 +824,25 @@ class A {
         new JCommander(a).parse("b");
     }
 
+    static class PathValidator implements IParameterValidator {
+        @Override
+        public void validate(String name, String value) throws ParameterException {
+            if (value.contains("\0"))
+                throw new ParameterException("this message comes from the validator (not from the converter)");
+        }
+    }
+
+    @Test(expectedExceptions = ParameterException.class, expectedExceptionsMessageRegExp = "this message comes from the validator \\(not from the converter\\)")
+    public void mainParameterShouldBeValidatedBEFOREConversion() throws Throwable {
+        class A {
+            @Parameter(validateWith = PathValidator.class, converter = PathConverter.class)
+            public Path path;
+        }
+
+        A a = new A();
+        new JCommander(a).parse("invalid\0/path");
+    }
+
     @Parameters(commandNames = {"--configure"})
     public static class ConfigureArgs {
     }