From 2f9cfc200f5afd0d946fb7b113b178f3be7dab87 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=BD=D0=B0=D0=B1?= <nabijaczleweli@nabijaczleweli.xyz>
Date: Wed, 8 Oct 2025 18:11:30 +0200
Subject: [PATCH 1/2] Deduplicate append_path_with_name()'s [l]stat() error
 handler

---
 src/builder.rs | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/src/builder.rs b/src/builder.rs
index f2d29464..b2e9e7b4 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -606,20 +606,16 @@ fn append_path_with_name(
     options: BuilderOptions,
 ) -> io::Result<()> {
     let stat = if options.follow {
-        fs::metadata(path).map_err(|err| {
-            io::Error::new(
-                err.kind(),
-                format!("{} when getting metadata for {}", err, path.display()),
-            )
-        })?
+        fs::metadata(path)
     } else {
-        fs::symlink_metadata(path).map_err(|err| {
-            io::Error::new(
-                err.kind(),
-                format!("{} when getting metadata for {}", err, path.display()),
-            )
-        })?
-    };
+        fs::symlink_metadata(path)
+    }
+    .map_err(|err| {
+        io::Error::new(
+            err.kind(),
+            format!("{} when getting metadata for {}", err, path.display()),
+        )
+    })?;
     let ar_name = name.unwrap_or(path);
     if stat.is_file() {
         append_file(dst, ar_name, &mut fs::File::open(path)?, options)

From d07bc3e83d7390a454ae492a426ffb3c7f8e49cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=BD=D0=B0=D0=B1?= <nabijaczleweli@nabijaczleweli.xyz>
Date: Wed, 8 Oct 2025 18:27:25 +0200
Subject: [PATCH 2/2] Don't follow symlinks in append_dir_all() if
 follow_symlinks(false)

Before (append_dir_all("file")):
  called `Result::unwrap()` on an `Err` value: Os { code: 20, kind: NotADirectory, message: "Not a directory" }
  called `Result::unwrap()` on an `Err` value: Os { code: 267, kind: NotADirectory, message: "The directory name is invalid." }
after (append_dir_all("file") or append_dir_all("symlink"):
  called `Result::unwrap()` on an `Err` value: Custom { kind: NotADirectory, error: "append_dir_all() argument not a directory" }

Repro with
  fn main() {
      let mut tar = tar::Builder::new(std::io::stdout().lock());
      tar.follow_symlinks(false);
      tar.append_dir_all("", std::env::args_os().nth(1).unwrap()) .unwrap();
      tar.finish().unwrap();
  }
before:
  $ ls -lnd src symlink Cargo.toml
  -rw-r--r-- 1 1000 100 118 10-08 18:31 Cargo.toml
  drwxr-xr-x 2 1000 100  60 10-08 17:57 src
  lrwxrwxrwx 1 1000 100   3 10-08 18:30 symlink -> src
  $ cargo run -- Cargo.toml | tar -tv
  called `Result::unwrap()` on an `Err` value: Os { code: 20, kind: NotADirectory, message: "Not a directory" }
  $ cargo run -- src | tar -tv
  -rw-r--r-- 1000/100        211 2025-10-08 18:29 main.rs
  $ cargo run -- symlink | tar -tv
  -rw-r--r-- 1000/100        211 2025-10-08 18:29 main.rs
after:
  $ cargo run -- Cargo.toml | tar -tv
  called `Result::unwrap()` on an `Err` value: Custom { kind: NotADirectory, error: "append_dir_all() argument not a directory" }
  $ cargo run -- src | tar -tv
  -rw-r--r-- 1000/100        211 2025-10-08 18:29 main.rs
  $ cargo run -- symlink | tar -tv
  called `Result::unwrap()` on an `Err` value: Custom { kind: NotADirectory, error: "append_dir_all() argument not a directory" }

This also achieves parity with tar(1)
---
 src/builder.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/builder.rs b/src/builder.rs
index b2e9e7b4..abdf2442 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -870,7 +870,18 @@ fn append_dir_all(
     src_path: &Path,
     options: BuilderOptions,
 ) -> io::Result<()> {
-    let mut stack = vec![(src_path.to_path_buf(), true, false)];
+    let src_metadata = if options.follow {
+        fs::metadata(src_path)
+    } else {
+        fs::symlink_metadata(src_path)
+    }?;
+    if !src_metadata.is_dir() {
+        return Err(io::Error::new(
+            io::ErrorKind::NotADirectory,
+            "append_dir_all() argument not a directory",
+        ));
+    }
+    let mut stack = vec![(src_path.to_path_buf(), true, src_metadata.is_symlink())];
     while let Some((src, is_dir, is_symlink)) = stack.pop() {
         let dest = path.join(src.strip_prefix(src_path).unwrap());
         // In case of a symlink pointing to a directory, is_dir is false, but src.is_dir() will return true