From 17744022b109c7cc6d22a0a339569391abdca7a4 Mon Sep 17 00:00:00 2001
From: Takeru Ohta <phjgt308@gmail.com>
Date: Sun, 15 Feb 2026 20:12:38 +0900
Subject: [PATCH 1/4] fix: improve invalid_data_error macro to support format
 arguments

---
 src/lib.rs  | 4 ++--
 src/zlib.rs | 8 ++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 3b6c477..857557b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -9,10 +9,10 @@ extern crate alloc;
 
 macro_rules! invalid_data_error {
     ($fmt:expr) => {
-        invalid_data_error!($fmt, "")
+        ::core2::io::Error::new(::core2::io::ErrorKind::InvalidData, $fmt)
     };
     ($fmt:expr, $($arg:tt)*) => {
-        ::core2::io::Error::new(::core2::io::ErrorKind::InvalidData, $fmt)
+        ::core2::io::Error::new(::core2::io::ErrorKind::InvalidData, format!($fmt, $($arg)*))
     };
 }
 
diff --git a/src/zlib.rs b/src/zlib.rs
index 914c78e..6f8d460 100644
--- a/src/zlib.rs
+++ b/src/zlib.rs
@@ -932,4 +932,12 @@ mod tests {
         ];
         assert_eq!(buf, decoded_data);
     }
+
+    #[test]
+    fn issue_82() {
+        let encoded_data = [0x00, 0x00];
+        let error = Header::read_from(&encoded_data[..]).unwrap_err();
+        assert_eq!(error.kind(), io::ErrorKind::InvalidData);
+        assert!(error.to_string().contains("method=0"));
+    }
 }

From df5468f1c7a3d4ef3c9763e9f3cc91474aa378fd Mon Sep 17 00:00:00 2001
From: Takeru Ohta <phjgt308@gmail.com>
Date: Sun, 15 Feb 2026 20:14:57 +0900
Subject: [PATCH 2/4] fix: use alloc::format in invalid_data_error macro and
 improve formatting

---
 src/lib.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index 857557b..4a34510 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,7 +12,10 @@ macro_rules! invalid_data_error {
         ::core2::io::Error::new(::core2::io::ErrorKind::InvalidData, $fmt)
     };
     ($fmt:expr, $($arg:tt)*) => {
-        ::core2::io::Error::new(::core2::io::ErrorKind::InvalidData, format!($fmt, $($arg)*))
+        ::core2::io::Error::new(
+            ::core2::io::ErrorKind::InvalidData,
+            ::alloc::format!($fmt, $($arg)*),
+        )
     };
 }
 

From f1c59c15d51c6637e7b407399aa7daf0f637adb5 Mon Sep 17 00:00:00 2001
From: Takeru Ohta <phjgt308@gmail.com>
Date: Sun, 15 Feb 2026 20:16:06 +0900
Subject: [PATCH 3/4] fix: add feature gate for format macro in
 invalid_data_error

---
 src/lib.rs | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 4a34510..3e3cb36 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,10 +12,19 @@ macro_rules! invalid_data_error {
         ::core2::io::Error::new(::core2::io::ErrorKind::InvalidData, $fmt)
     };
     ($fmt:expr, $($arg:tt)*) => {
-        ::core2::io::Error::new(
-            ::core2::io::ErrorKind::InvalidData,
-            ::alloc::format!($fmt, $($arg)*),
-        )
+        {
+            #[cfg(feature = "std")]
+            {
+                ::core2::io::Error::new(
+                    ::core2::io::ErrorKind::InvalidData,
+                    ::alloc::format!($fmt, $($arg)*),
+                )
+            }
+            #[cfg(not(feature = "std"))]
+            {
+                ::core2::io::Error::new(::core2::io::ErrorKind::InvalidData, $fmt)
+            }
+        }
     };
 }
 

From ddbcb3cfce18724720e21aaaea33c5436f9be495 Mon Sep 17 00:00:00 2001
From: Takeru Ohta <phjgt308@gmail.com>
Date: Sun, 15 Feb 2026 20:18:13 +0900
Subject: [PATCH 4/4] fix: add feature gate for issue_82 test

---
 src/zlib.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/zlib.rs b/src/zlib.rs
index 6f8d460..c45ae8e 100644
--- a/src/zlib.rs
+++ b/src/zlib.rs
@@ -934,6 +934,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg(feature = "std")]
     fn issue_82() {
         let encoded_data = [0x00, 0x00];
         let error = Header::read_from(&encoded_data[..]).unwrap_err();