std.tar: don't return in iterator init

Don't assert min buffer size on iterator init. That was changing public
interface. This way we don't break that interface.

2 files changed, 320 insertions, 314 deletions

diff --git a/lib/std/tar.zig b/lib/std/tar.zig
index 0eab2456d7..6bf46ad507 100644
--- a/lib/std/tar.zig
+++ b/lib/std/tar.zig
@@ -115,9 +115,10 @@ pub const Header = struct {
 
     /// Includes prefix concatenated, if any.
     /// TODO: check against "../" and other nefarious things
-    pub fn fullName(header: Header, buffer: *[MAX_NAME_SIZE]u8) ![]const u8 {
+    pub fn fullName(header: Header, buffer: []u8) ![]const u8 {
         const n = name(header);
         const p = prefix(header);
+        if (buffer.len < n.len + p.len + 1) return error.TarInsufficientBuffer;
         if (!is_ustar(header) or p.len == 0) {
             @memcpy(buffer[0..n.len], n);
             return buffer[0..n.len];
@@ -130,11 +131,12 @@ pub const Header = struct {
 
     /// When kind is symbolic_link linked-to name (target_path) is specified in
     /// the linkname field.
-    pub fn linkName(header: Header, buffer: *[LINK_NAME_SIZE]u8) []const u8 {
+    pub fn linkName(header: Header, buffer: []u8) ![]const u8 {
         const link_name = header.str(157, 100);
         if (link_name.len == 0) {
             return buffer[0..0];
         }
+        if (buffer.len < link_name.len) return error.TarInsufficientBuffer;
         const buf = buffer[0..link_name.len];
         @memcpy(buf, link_name);
         return buf;
@@ -248,13 +250,7 @@ pub const IteratorOptions = struct {
 
 /// Iterates over files in tar archive.
 /// `next` returns each file in `reader` tar archive.
-/// Provided buffers should be at least 256 bytes for file_name and 100 bytes
-/// for link_name.
-pub fn iterator(reader: anytype, options: IteratorOptions) !Iterator(@TypeOf(reader)) {
-    if (options.file_name_buffer.len < Header.MAX_NAME_SIZE or
-        options.link_name_buffer.len < Header.LINK_NAME_SIZE)
-        return error.TarInsufficientBuffer;
-
+pub fn iterator(reader: anytype, options: IteratorOptions) Iterator(@TypeOf(reader)) {
     return .{
         .reader = reader,
         .diagnostics = options.diagnostics,
@@ -372,10 +368,10 @@ fn Iterator(comptime ReaderType: type) type {
                             self.file.size = size;
                         }
                         if (self.file.link_name.len == 0) {
-                            self.file.link_name = header.linkName(self.link_name_buffer[0..Header.LINK_NAME_SIZE]);
+                            self.file.link_name = try header.linkName(self.link_name_buffer);
                         }
                         if (self.file.name.len == 0) {
-                            self.file.name = try header.fullName(self.file_name_buffer[0..Header.MAX_NAME_SIZE]);
+                            self.file.name = try header.fullName(self.file_name_buffer);
                         }
 
                         self.padding = blockPadding(self.file.size);
@@ -565,7 +561,7 @@ pub fn pipeToFileSystem(dir: std.fs.Dir, reader: anytype, options: Options) !voi
 
     var file_name_buffer: [std.fs.MAX_PATH_BYTES]u8 = undefined;
     var link_name_buffer: [std.fs.MAX_PATH_BYTES]u8 = undefined;
-    var iter = try iterator(reader, .{
+    var iter = iterator(reader, .{
         .file_name_buffer = &file_name_buffer,
         .link_name_buffer = &link_name_buffer,
         .diagnostics = options.diagnostics,
@@ -871,17 +867,3 @@ test "create file and symlink" {
     _ = try createDirAndSymlink(root.dir, "../../../g/h/i/file4", "j/k/l/symlink3");
     _ = try createDirAndFile(root.dir, "g/h/i/file4");
 }
-
-test "insufficient buffer for iterator" {
-    var file_name_buffer: [10]u8 = undefined;
-    var link_name_buffer: [10]u8 = undefined;
-
-    var fsb = std.io.fixedBufferStream("");
-    try std.testing.expectError(
-        error.TarInsufficientBuffer,
-        iterator(fsb.reader(), .{
-            .file_name_buffer = &file_name_buffer,
-            .link_name_buffer = &link_name_buffer,
-        }),
-    );
-}
diff --git a/lib/std/tar/test.zig b/lib/std/tar/test.zig
index 9532306728..7cd0cb7544 100644
--- a/lib/std/tar/test.zig
+++ b/lib/std/tar/test.zig
@@ -2,333 +2,352 @@ const std = @import("std");
 const tar = @import("../tar.zig");
 const testing = std.testing;
 
-test "run test cases" {
-    const Case = struct {
-        const File = struct {
-            name: []const u8,
-            size: u64 = 0,
-            mode: u32 = 0,
-            link_name: []const u8 = &[0]u8{},
-            kind: tar.Header.Kind = .normal,
-            truncated: bool = false, // when there is no file body, just header, usefull for huge files
-        };
-
-        data: []const u8, // testdata file content
-        files: []const File = &[_]@This().File{}, // expected files to found in archive
-        chksums: []const []const u8 = &[_][]const u8{}, // chksums of each file content
-        err: ?anyerror = null, // parsing should fail with this error
+const Case = struct {
+    const File = struct {
+        name: []const u8,
+        size: u64 = 0,
+        mode: u32 = 0,
+        link_name: []const u8 = &[0]u8{},
+        kind: tar.Header.Kind = .normal,
+        truncated: bool = false, // when there is no file body, just header, usefull for huge files
     };
 
-    const cases = [_]Case{
-        .{
-            .data = @embedFile("testdata/gnu.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "small.txt",
-                    .size = 5,
-                    .mode = 0o640,
-                },
-                .{
-                    .name = "small2.txt",
-                    .size = 11,
-                    .mode = 0o640,
-                },
+    data: []const u8, // testdata file content
+    files: []const File = &[_]@This().File{}, // expected files to found in archive
+    chksums: []const []const u8 = &[_][]const u8{}, // chksums of each file content
+    err: ?anyerror = null, // parsing should fail with this error
+};
+
+const cases = [_]Case{
+    .{
+        .data = @embedFile("testdata/gnu.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "small.txt",
+                .size = 5,
+                .mode = 0o640,
             },
-            .chksums = &[_][]const u8{
-                "e38b27eaccb4391bdec553a7f3ae6b2f",
-                "c65bd2e50a56a2138bf1716f2fd56fe9",
+            .{
+                .name = "small2.txt",
+                .size = 11,
+                .mode = 0o640,
             },
         },
-        .{
-            .data = @embedFile("testdata/sparse-formats.tar"),
-            .err = error.TarUnsupportedHeader,
+        .chksums = &[_][]const u8{
+            "e38b27eaccb4391bdec553a7f3ae6b2f",
+            "c65bd2e50a56a2138bf1716f2fd56fe9",
         },
-        .{
-            .data = @embedFile("testdata/star.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "small.txt",
-                    .size = 5,
-                    .mode = 0o640,
-                },
-                .{
-                    .name = "small2.txt",
-                    .size = 11,
-                    .mode = 0o640,
-                },
+    },
+    .{
+        .data = @embedFile("testdata/sparse-formats.tar"),
+        .err = error.TarUnsupportedHeader,
+    },
+    .{
+        .data = @embedFile("testdata/star.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "small.txt",
+                .size = 5,
+                .mode = 0o640,
             },
-            .chksums = &[_][]const u8{
-                "e38b27eaccb4391bdec553a7f3ae6b2f",
-                "c65bd2e50a56a2138bf1716f2fd56fe9",
+            .{
+                .name = "small2.txt",
+                .size = 11,
+                .mode = 0o640,
             },
         },
-        .{
-            .data = @embedFile("testdata/v7.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "small.txt",
-                    .size = 5,
-                    .mode = 0o444,
-                },
-                .{
-                    .name = "small2.txt",
-                    .size = 11,
-                    .mode = 0o444,
-                },
-            },
-            .chksums = &[_][]const u8{
-                "e38b27eaccb4391bdec553a7f3ae6b2f",
-                "c65bd2e50a56a2138bf1716f2fd56fe9",
-            },
+        .chksums = &[_][]const u8{
+            "e38b27eaccb4391bdec553a7f3ae6b2f",
+            "c65bd2e50a56a2138bf1716f2fd56fe9",
         },
-        .{
-            .data = @embedFile("testdata/pax.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "a/123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100",
-                    .size = 7,
-                    .mode = 0o664,
-                },
-                .{
-                    .name = "a/b",
-                    .size = 0,
-                    .kind = .symbolic_link,
-                    .mode = 0o777,
-                    .link_name = "123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100",
-                },
+    },
+    .{
+        .data = @embedFile("testdata/v7.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "small.txt",
+                .size = 5,
+                .mode = 0o444,
             },
-            .chksums = &[_][]const u8{
-                "3c382e8f5b6631aa2db52643912ffd4a",
+            .{
+                .name = "small2.txt",
+                .size = 11,
+                .mode = 0o444,
             },
         },
-        .{
-            // pax attribute don't end with \n
-            .data = @embedFile("testdata/pax-bad-hdr-file.tar"),
-            .err = error.PaxInvalidAttributeEnd,
+        .chksums = &[_][]const u8{
+            "e38b27eaccb4391bdec553a7f3ae6b2f",
+            "c65bd2e50a56a2138bf1716f2fd56fe9",
         },
-        .{
-            // size is in pax attribute
-            .data = @embedFile("testdata/pax-pos-size-file.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "foo",
-                    .size = 999,
-                    .kind = .normal,
-                    .mode = 0o640,
-                },
+    },
+    .{
+        .data = @embedFile("testdata/pax.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "a/123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100",
+                .size = 7,
+                .mode = 0o664,
             },
-            .chksums = &[_][]const u8{
-                "0afb597b283fe61b5d4879669a350556",
+            .{
+                .name = "a/b",
+                .size = 0,
+                .kind = .symbolic_link,
+                .mode = 0o777,
+                .link_name = "123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100",
             },
         },
-        .{
-            // has pax records which we are not interested in
-            .data = @embedFile("testdata/pax-records.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "file",
-                },
+        .chksums = &[_][]const u8{
+            "3c382e8f5b6631aa2db52643912ffd4a",
+        },
+    },
+    .{
+        // pax attribute don't end with \n
+        .data = @embedFile("testdata/pax-bad-hdr-file.tar"),
+        .err = error.PaxInvalidAttributeEnd,
+    },
+    .{
+        // size is in pax attribute
+        .data = @embedFile("testdata/pax-pos-size-file.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "foo",
+                .size = 999,
+                .kind = .normal,
+                .mode = 0o640,
             },
         },
-        .{
-            // has global records which we are ignoring
-            .data = @embedFile("testdata/pax-global-records.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "file1",
-                },
-                .{
-                    .name = "file2",
-                },
-                .{
-                    .name = "file3",
-                },
-                .{
-                    .name = "file4",
-                },
+        .chksums = &[_][]const u8{
+            "0afb597b283fe61b5d4879669a350556",
+        },
+    },
+    .{
+        // has pax records which we are not interested in
+        .data = @embedFile("testdata/pax-records.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "file",
             },
         },
-        .{
-            .data = @embedFile("testdata/nil-uid.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "P1050238.JPG.log",
-                    .size = 14,
-                    .kind = .normal,
-                    .mode = 0o664,
-                },
+    },
+    .{
+        // has global records which we are ignoring
+        .data = @embedFile("testdata/pax-global-records.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "file1",
             },
-            .chksums = &[_][]const u8{
-                "08d504674115e77a67244beac19668f5",
+            .{
+                .name = "file2",
             },
-        },
-        .{
-            // has xattrs and pax records which we are ignoring
-            .data = @embedFile("testdata/xattrs.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "small.txt",
-                    .size = 5,
-                    .kind = .normal,
-                    .mode = 0o644,
-                },
-                .{
-                    .name = "small2.txt",
-                    .size = 11,
-                    .kind = .normal,
-                    .mode = 0o644,
-                },
+            .{
+                .name = "file3",
             },
-            .chksums = &[_][]const u8{
-                "e38b27eaccb4391bdec553a7f3ae6b2f",
-                "c65bd2e50a56a2138bf1716f2fd56fe9",
+            .{
+                .name = "file4",
             },
         },
-        .{
-            .data = @embedFile("testdata/gnu-multi-hdrs.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "GNU2/GNU2/long-path-name",
-                    .link_name = "GNU4/GNU4/long-linkpath-name",
-                    .kind = .symbolic_link,
-                },
+    },
+    .{
+        .data = @embedFile("testdata/nil-uid.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "P1050238.JPG.log",
+                .size = 14,
+                .kind = .normal,
+                .mode = 0o664,
             },
         },
-        .{
-            // has gnu type D (directory) and S (sparse) blocks
-            .data = @embedFile("testdata/gnu-incremental.tar"),
-            .err = error.TarUnsupportedHeader,
+        .chksums = &[_][]const u8{
+            "08d504674115e77a67244beac19668f5",
         },
-        .{
-            // should use values only from last pax header
-            .data = @embedFile("testdata/pax-multi-hdrs.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "bar",
-                    .link_name = "PAX4/PAX4/long-linkpath-name",
-                    .kind = .symbolic_link,
-                },
+    },
+    .{
+        // has xattrs and pax records which we are ignoring
+        .data = @embedFile("testdata/xattrs.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "small.txt",
+                .size = 5,
+                .kind = .normal,
+                .mode = 0o644,
             },
-        },
-        .{
-            .data = @embedFile("testdata/gnu-long-nul.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "0123456789",
-                    .mode = 0o644,
-                },
+            .{
+                .name = "small2.txt",
+                .size = 11,
+                .kind = .normal,
+                .mode = 0o644,
             },
         },
-        .{
-            .data = @embedFile("testdata/gnu-utf8.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹",
-                    .mode = 0o644,
-                },
-            },
+        .chksums = &[_][]const u8{
+            "e38b27eaccb4391bdec553a7f3ae6b2f",
+            "c65bd2e50a56a2138bf1716f2fd56fe9",
         },
-        .{
-            .data = @embedFile("testdata/gnu-not-utf8.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "hi\x80\x81\x82\x83bye",
-                    .mode = 0o644,
-                },
+    },
+    .{
+        .data = @embedFile("testdata/gnu-multi-hdrs.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "GNU2/GNU2/long-path-name",
+                .link_name = "GNU4/GNU4/long-linkpath-name",
+                .kind = .symbolic_link,
             },
         },
-        .{
-            // null in pax key
-            .data = @embedFile("testdata/pax-nul-xattrs.tar"),
-            .err = error.PaxNullInKeyword,
-        },
-        .{
-            .data = @embedFile("testdata/pax-nul-path.tar"),
-            .err = error.PaxNullInValue,
-        },
-        .{
-            .data = @embedFile("testdata/neg-size.tar"),
-            .err = error.TarHeader,
-        },
-        .{
-            .data = @embedFile("testdata/issue10968.tar"),
-            .err = error.TarHeader,
-        },
-        .{
-            .data = @embedFile("testdata/issue11169.tar"),
-            .err = error.TarHeader,
+    },
+    .{
+        // has gnu type D (directory) and S (sparse) blocks
+        .data = @embedFile("testdata/gnu-incremental.tar"),
+        .err = error.TarUnsupportedHeader,
+    },
+    .{
+        // should use values only from last pax header
+        .data = @embedFile("testdata/pax-multi-hdrs.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "bar",
+                .link_name = "PAX4/PAX4/long-linkpath-name",
+                .kind = .symbolic_link,
+            },
         },
-        .{
-            .data = @embedFile("testdata/issue12435.tar"),
-            .err = error.TarHeaderChksum,
+    },
+    .{
+        .data = @embedFile("testdata/gnu-long-nul.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "0123456789",
+                .mode = 0o644,
+            },
         },
-        .{
-            // has magic with space at end instead of null
-            .data = @embedFile("testdata/invalid-go17.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/foo",
-                },
+    },
+    .{
+        .data = @embedFile("testdata/gnu-utf8.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹☺☻☹",
+                .mode = 0o644,
             },
         },
-        .{
-            .data = @embedFile("testdata/ustar-file-devs.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "file",
-                    .mode = 0o644,
-                },
+    },
+    .{
+        .data = @embedFile("testdata/gnu-not-utf8.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "hi\x80\x81\x82\x83bye",
+                .mode = 0o644,
             },
         },
-        .{
-            .data = @embedFile("testdata/trailing-slash.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "123456789/" ** 30,
-                    .kind = .directory,
-                },
+    },
+    .{
+        // null in pax key
+        .data = @embedFile("testdata/pax-nul-xattrs.tar"),
+        .err = error.PaxNullInKeyword,
+    },
+    .{
+        .data = @embedFile("testdata/pax-nul-path.tar"),
+        .err = error.PaxNullInValue,
+    },
+    .{
+        .data = @embedFile("testdata/neg-size.tar"),
+        .err = error.TarHeader,
+    },
+    .{
+        .data = @embedFile("testdata/issue10968.tar"),
+        .err = error.TarHeader,
+    },
+    .{
+        .data = @embedFile("testdata/issue11169.tar"),
+        .err = error.TarHeader,
+    },
+    .{
+        .data = @embedFile("testdata/issue12435.tar"),
+        .err = error.TarHeaderChksum,
+    },
+    .{
+        // has magic with space at end instead of null
+        .data = @embedFile("testdata/invalid-go17.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/foo",
             },
         },
-        .{
-            // Has size in gnu extended format. To represent size bigger than 8 GB.
-            .data = @embedFile("testdata/writer-big.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "tmp/16gig.txt",
-                    .size = 16 * 1024 * 1024 * 1024,
-                    .truncated = true,
-                    .mode = 0o640,
-                },
+    },
+    .{
+        .data = @embedFile("testdata/ustar-file-devs.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "file",
+                .mode = 0o644,
             },
         },
-        .{
-            // Size in gnu extended format, and name in pax attribute.
-            .data = @embedFile("testdata/writer-big-long.tar"),
-            .files = &[_]Case.File{
-                .{
-                    .name = "longname/" ** 15 ++ "16gig.txt",
-                    .size = 16 * 1024 * 1024 * 1024,
-                    .mode = 0o644,
-                    .truncated = true,
-                },
+    },
+    .{
+        .data = @embedFile("testdata/trailing-slash.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "123456789/" ** 30,
+                .kind = .directory,
             },
         },
-        .{
-            .data = @embedFile("testdata/fuzz1.tar"),
-            .err = error.TarInsufficientBuffer,
+    },
+    .{
+        // Has size in gnu extended format. To represent size bigger than 8 GB.
+        .data = @embedFile("testdata/writer-big.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "tmp/16gig.txt",
+                .size = 16 * 1024 * 1024 * 1024,
+                .truncated = true,
+                .mode = 0o640,
+            },
         },
-        .{
-            .data = @embedFile("testdata/fuzz2.tar"),
-            .err = error.PaxSizeAttrOverflow,
+    },
+    .{
+        // Size in gnu extended format, and name in pax attribute.
+        .data = @embedFile("testdata/writer-big-long.tar"),
+        .files = &[_]Case.File{
+            .{
+                .name = "longname/" ** 15 ++ "16gig.txt",
+                .size = 16 * 1024 * 1024 * 1024,
+                .mode = 0o644,
+                .truncated = true,
+            },
         },
-    };
+    },
+    .{
+        .data = @embedFile("testdata/fuzz1.tar"),
+        .err = error.TarInsufficientBuffer,
+    },
+    .{
+        .data = @embedFile("testdata/fuzz2.tar"),
+        .err = error.PaxSizeAttrOverflow,
+    },
+};
+
+// used in test to calculate file chksum
+const Md5Writer = struct {
+    h: std.crypto.hash.Md5 = std.crypto.hash.Md5.init(.{}),
+
+    pub fn writeAll(self: *Md5Writer, buf: []const u8) !void {
+        self.h.update(buf);
+    }
+
+    pub fn writeByte(self: *Md5Writer, byte: u8) !void {
+        self.h.update(&[_]u8{byte});
+    }
 
+    pub fn chksum(self: *Md5Writer) [32]u8 {
+        var s = [_]u8{0} ** 16;
+        self.h.final(&s);
+        return std.fmt.bytesToHex(s, .lower);
+    }
+};
+
+test "run test cases" {
     var file_name_buffer: [std.fs.MAX_PATH_BYTES]u8 = undefined;
     var link_name_buffer: [std.fs.MAX_PATH_BYTES]u8 = undefined;
 
     for (cases) |case| {
         var fsb = std.io.fixedBufferStream(case.data);
-        var iter = try tar.iterator(fsb.reader(), .{
+        var iter = tar.iterator(fsb.reader(), .{
             .file_name_buffer = &file_name_buffer,
             .link_name_buffer = &link_name_buffer,
         });
@@ -359,6 +378,10 @@ test "run test cases" {
         }
         try testing.expectEqual(case.files.len, i);
     }
+}
+
+test "pax/gnu long names with small buffer" {
+    // should fail with insufficient buffer error
 
     var min_file_name_buffer: [tar.Header.MAX_NAME_SIZE]u8 = undefined;
     var min_link_name_buffer: [tar.Header.LINK_NAME_SIZE]u8 = undefined;
@@ -366,7 +389,7 @@ test "run test cases" {
 
     for (long_name_cases) |case| {
         var fsb = std.io.fixedBufferStream(case.data);
-        var iter = try tar.iterator(fsb.reader(), .{
+        var iter = tar.iterator(fsb.reader(), .{
             .file_name_buffer = &min_file_name_buffer,
             .link_name_buffer = &min_link_name_buffer,
         });
@@ -382,24 +405,25 @@ test "run test cases" {
     }
 }
 
-// used in test to calculate file chksum
-const Md5Writer = struct {
-    h: std.crypto.hash.Md5 = std.crypto.hash.Md5.init(.{}),
+test "insufficient buffer in Header name filed" {
+    var min_file_name_buffer: [9]u8 = undefined;
+    var min_link_name_buffer: [tar.Header.LINK_NAME_SIZE]u8 = undefined;
 
-    pub fn writeAll(self: *Md5Writer, buf: []const u8) !void {
-        self.h.update(buf);
-    }
+    var fsb = std.io.fixedBufferStream(cases[0].data);
+    var iter = tar.iterator(fsb.reader(), .{
+        .file_name_buffer = &min_file_name_buffer,
+        .link_name_buffer = &min_link_name_buffer,
+    });
 
-    pub fn writeByte(self: *Md5Writer, byte: u8) !void {
-        self.h.update(&[_]u8{byte});
-    }
+    var iter_err: ?anyerror = null;
+    while (iter.next() catch |err| brk: {
+        iter_err = err;
+        break :brk null;
+    }) |_| {}
 
-    pub fn chksum(self: *Md5Writer) [32]u8 {
-        var s = [_]u8{0} ** 16;
-        self.h.final(&s);
-        return std.fmt.bytesToHex(s, .lower);
-    }
-};
+    try testing.expect(iter_err != null);
+    try testing.expectEqual(error.TarInsufficientBuffer, iter_err.?);
+}
 
 test "should not overwrite existing file" {
     // Starting from this folder structure: