From e510a036a2e6673f3ff4bafbf9f717c7ea20b988 Mon Sep 17 00:00:00 2001
From: Faizzyhon <68625839+faizzyhon@users.noreply.github.com>
Date: Thu, 7 May 2026 02:21:50 +0300
Subject: [PATCH 1/5] fix: int_to_roman silently returns wrong values for
 out-of-range input

Added input validation for int_to_roman function.
---
 conversions/roman_numerals.py | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/conversions/roman_numerals.py b/conversions/roman_numerals.py
index 75af2ac72882..2f3af8ed36fb 100644
--- a/conversions/roman_numerals.py
+++ b/conversions/roman_numerals.py
@@ -40,12 +40,37 @@ def roman_to_int(roman: str) -> int:
 
 def int_to_roman(number: int) -> str:
     """
-    Given a integer, convert it to an roman numeral.
+    Given an integer, convert it to a Roman numeral.
+    Input must be an integer in the range 1 to 3999.
     https://en.wikipedia.org/wiki/Roman_numerals
     >>> tests = {"III": 3, "CLIV": 154, "MIX": 1009, "MMD": 2500, "MMMCMXCIX": 3999}
     >>> all(int_to_roman(value) == key for key, value in tests.items())
     True
+    >>> int_to_roman(0)
+    Traceback (most recent call last):
+        ...
+    ValueError: int_to_roman only accepts integers in the range 1 to 3999, got 0
+    >>> int_to_roman(-1)
+    Traceback (most recent call last):
+        ...
+    ValueError: int_to_roman only accepts integers in the range 1 to 3999, got -1
+    >>> int_to_roman(4000)
+    Traceback (most recent call last):
+        ...
+    ValueError: int_to_roman only accepts integers in the range 1 to 3999, got 4000
+    >>> int_to_roman(True)
+    Traceback (most recent call last):
+        ...
+    TypeError: int_to_roman only accepts integers, got bool
     """
+    if not isinstance(number, int) or isinstance(number, bool):
+        raise TypeError(
+            f"int_to_roman only accepts integers, got {type(number).__name__}"
+        )
+    if not 1 <= number <= 3999:
+        raise ValueError(
+            f"int_to_roman only accepts integers in the range 1 to 3999, got {number}"
+        )
     result = []
     for arabic, roman in ROMAN:
         (factor, number) = divmod(number, arabic)

From 96d953ef3d2c1ca3ab1aaa437a5e14f060d11594 Mon Sep 17 00:00:00 2001
From: Faizzyhon <68625839+faizzyhon@users.noreply.github.com>
Date: Wed, 6 May 2026 16:34:50 -0700
Subject: [PATCH 2/5] fix: EM102 assign f-strings to msg before raising
 exceptions

---
 conversions/roman_numerals.py | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/conversions/roman_numerals.py b/conversions/roman_numerals.py
index 2f3af8ed36fb..40ee2203d0f5 100644
--- a/conversions/roman_numerals.py
+++ b/conversions/roman_numerals.py
@@ -64,13 +64,11 @@ def int_to_roman(number: int) -> str:
     TypeError: int_to_roman only accepts integers, got bool
     """
     if not isinstance(number, int) or isinstance(number, bool):
-        raise TypeError(
-            f"int_to_roman only accepts integers, got {type(number).__name__}"
-        )
+        msg = f"int_to_roman only accepts integers, got {type(number).__name__}"
+        raise TypeError(msg)
     if not 1 <= number <= 3999:
-        raise ValueError(
-            f"int_to_roman only accepts integers in the range 1 to 3999, got {number}"
-        )
+        msg = f"int_to_roman only accepts integers in the range 1 to 3999, got {number}"
+        raise ValueError(msg)
     result = []
     for arabic, roman in ROMAN:
         (factor, number) = divmod(number, arabic)

From d953d37b9b8dccc8796fa5d0e81acac7159c7046 Mon Sep 17 00:00:00 2001
From: Christian Clauss <cclauss@me.com>
Date: Wed, 16 Sep 2026 20:04:20 +0200
Subject: [PATCH 3/5] Update conversions/roman_numerals.py

---
 conversions/roman_numerals.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/conversions/roman_numerals.py b/conversions/roman_numerals.py
index 40ee2203d0f5..e2f49c4e3586 100644
--- a/conversions/roman_numerals.py
+++ b/conversions/roman_numerals.py
@@ -63,7 +63,7 @@ def int_to_roman(number: int) -> str:
         ...
     TypeError: int_to_roman only accepts integers, got bool
     """
-    if not isinstance(number, int) or isinstance(number, bool):
+    if not isinstance(number, (bool, int)):
         msg = f"int_to_roman only accepts integers, got {type(number).__name__}"
         raise TypeError(msg)
     if not 1 <= number <= 3999:

From 273af2cd31b973e2498d571f2cb961c87da62d3f Mon Sep 17 00:00:00 2001
From: Christian Clauss <cclauss@me.com>
Date: Wed, 16 Sep 2026 20:08:44 +0200
Subject: [PATCH 4/5] Bool don't work

---
 conversions/roman_numerals.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/conversions/roman_numerals.py b/conversions/roman_numerals.py
index e2f49c4e3586..032cd9389197 100644
--- a/conversions/roman_numerals.py
+++ b/conversions/roman_numerals.py
@@ -63,7 +63,7 @@ def int_to_roman(number: int) -> str:
         ...
     TypeError: int_to_roman only accepts integers, got bool
     """
-    if not isinstance(number, (bool, int)):
+    if not isinstance(number, int):
         msg = f"int_to_roman only accepts integers, got {type(number).__name__}"
         raise TypeError(msg)
     if not 1 <= number <= 3999:

From 83346fe8655609daa1f615b012b23f19ece4d652 Mon Sep 17 00:00:00 2001
From: Christian Clauss <cclauss@me.com>
Date: Wed, 16 Sep 2026 21:18:28 +0200
Subject: [PATCH 5/5] Apply suggestion from @cclauss

---
 conversions/roman_numerals.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/conversions/roman_numerals.py b/conversions/roman_numerals.py
index 032cd9389197..7764ee0d8de5 100644
--- a/conversions/roman_numerals.py
+++ b/conversions/roman_numerals.py
@@ -63,7 +63,7 @@ def int_to_roman(number: int) -> str:
         ...
     TypeError: int_to_roman only accepts integers, got bool
     """
-    if not isinstance(number, int):
+    if isinstance(number, bool) or not isinstance(number, int):
         msg = f"int_to_roman only accepts integers, got {type(number).__name__}"
         raise TypeError(msg)
     if not 1 <= number <= 3999: