Synchronize PaxTarEntry ExtendedAttributes with property setters

src/libraries/System.Formats.Tar/src/System/Formats/Tar/PaxTarEntry.cs

@@ -46,12 +46,13 @@ public PaxTarEntry(TarEntryType entryType, string entryName)
         /// <param name="entryType">The type of the entry.</param>
         /// <param name="entryName">A string with the path and file name of this entry.</param>
         /// <param name="extendedAttributes">An enumeration of string key-value pairs that represents the metadata to include in the Extended Attributes entry that precedes the current entry.</param>
-        /// <remarks>When creating an instance using the <see cref="PaxTarEntry(TarEntryType, string)"/> constructor, only the following entry types are supported:
+        /// <remarks><para>When creating an instance using the <see cref="PaxTarEntry(TarEntryType, string, IEnumerable{KeyValuePair{string, string}})"/> constructor, only the following entry types are supported:</para>
         /// <list type="bullet">
         /// <item>In all platforms: <see cref="TarEntryType.Directory"/>, <see cref="TarEntryType.HardLink"/>, <see cref="TarEntryType.SymbolicLink"/>, <see cref="TarEntryType.RegularFile"/>.</item>
         /// <item>In Unix platforms only: <see cref="TarEntryType.BlockDevice"/>, <see cref="TarEntryType.CharacterDevice"/> and <see cref="TarEntryType.Fifo"/>.</item>
         /// </list>
-        /// The specified <paramref name="extendedAttributes"/> are additional attributes to be used for the entry.
+        /// <para>The specified <paramref name="extendedAttributes"/> are additional attributes to be used for the entry. If any of the provided extended attributes correspond to standard entry properties (such as <c>path</c>, <c>mtime</c>, <c>uid</c>, <c>gid</c>, <c>uname</c>, <c>gname</c>, <c>linkpath</c>, <c>devmajor</c>, or <c>devminor</c>), those values are applied to the corresponding properties. The <paramref name="entryName"/> parameter always takes precedence over a <c>path</c> extended attribute if both are specified.</para>
+        /// <para>Setting a property after construction will update the corresponding extended attribute.</para>
         /// <para>It may include PAX attributes like:</para>
         /// <list type="bullet">
         /// <item>Access time, under the name <c>atime</c>, as a <see cref="double"/> number.</item>
@@ -68,7 +69,11 @@ public PaxTarEntry(TarEntryType entryType, string entryName, IEnumerable<KeyValu
             ArgumentNullException.ThrowIfNull(extendedAttributes);
 
             _header._prefix = string.Empty;
-            _header.AddExtendedAttributes(extendedAttributes);
+            _header.ReplaceNormalAttributesWithExtended(extendedAttributes);
+
+            // The entryName parameter takes precedence over a "path" extended attribute.
+            _header._name = entryName;
+            _header.ExtendedAttributes[TarHeader.PaxEaName] = entryName;
         }
 
         /// <summary>
@@ -90,7 +95,7 @@ public PaxTarEntry(TarEntry other)
 
             if (other is PaxTarEntry paxOther)
             {
-                _header.AddExtendedAttributes(paxOther.ExtendedAttributes);
+                _header.ReplaceNormalAttributesWithExtended(paxOther.ExtendedAttributes);
             }
             else if (other is GnuTarEntry gnuOther)
             {
@@ -108,7 +113,8 @@ public PaxTarEntry(TarEntry other)
         /// <summary>
         /// Returns the extended attributes for this entry.
         /// </summary>
-        /// <remarks>The extended attributes are specified when constructing an entry and updated with additional attributes when the entry is written. Use <see cref="PaxTarEntry(TarEntryType, string, IEnumerable{KeyValuePair{string, string}})"/> to append custom extended attributes.
+        /// <remarks>The extended attributes are specified when constructing an entry. All provided extended attributes are preserved, including those whose values fit within the standard header fields.
+        /// <para>Setting properties such as <see cref="TarEntry.Name"/>, <see cref="TarEntry.ModificationTime"/>, <see cref="TarEntry.Uid"/>, <see cref="TarEntry.Gid"/>, <see cref="PosixTarEntry.UserName"/>, <see cref="PosixTarEntry.GroupName"/>, <see cref="TarEntry.LinkName"/>, <see cref="PosixTarEntry.DeviceMajor"/>, or <see cref="PosixTarEntry.DeviceMinor"/> will update the corresponding extended attribute to keep properties and extended attributes synchronized.</para>
         /// <para>The following common PAX attributes may be included:</para>
         /// <list type="bullet">
         /// <item>Modification time, under the name <c>mtime</c>, as a <see cref="double"/> number.</item>
@@ -120,7 +126,7 @@ public PaxTarEntry(TarEntry other)
         /// <item>File length, under the name <c>size</c>, as an <see cref="int"/>.</item>
         /// </list>
         /// </remarks>
-        public IReadOnlyDictionary<string, string> ExtendedAttributes => field ??= _header.ExtendedAttributes.AsReadOnly();
+        public IReadOnlyDictionary<string, string> ExtendedAttributes => field ??= _header.GetPopulatedExtendedAttributes().AsReadOnly();
 
         // Determines if the current instance's entry type supports setting a data stream.
         internal override bool IsDataStreamSetterSupported() => EntryType == TarEntryType.RegularFile;

src/libraries/System.Formats.Tar/src/System/Formats/Tar/PosixTarEntry.cs

@@ -48,7 +48,7 @@ internal PosixTarEntry(TarEntry other, TarEntryFormat format)
         /// <summary>
         /// When the current entry represents a character device or a block device, the major number identifies the driver associated with the device.
         /// </summary>
-        /// <remarks>Character and block devices are Unix-specific entry types.</remarks>
+        /// <remarks>Character and block devices are Unix-specific entry types. For PAX entries, setting this property updates the corresponding <c>devmajor</c> extended attribute in <see cref="PaxTarEntry.ExtendedAttributes"/>.</remarks>
         /// <exception cref="InvalidOperationException">The entry does not represent a block device or a character device.</exception>
         /// <exception cref="ArgumentOutOfRangeException">The value is negative, or larger than 2097151 when using <see cref="TarEntryFormat.V7"/> or <see cref="TarEntryFormat.Ustar"/>.</exception>
         public int DeviceMajor
@@ -64,17 +64,18 @@ public int DeviceMajor
                 ArgumentOutOfRangeException.ThrowIfNegative(value);
                 if (FormatIsOctalOnly)
                 {
-                    ArgumentOutOfRangeException.ThrowIfGreaterThan(value, 0x1FFFFF); // 7777777 in octal
+                    ArgumentOutOfRangeException.ThrowIfGreaterThan(value, TarHeader.Octal8ByteFieldMaxValue);
                 }
 
                 _header._devMajor = value;
+                _header.SyncNumericExtendedAttribute(TarHeader.PaxEaDevMajor, value, TarHeader.Octal8ByteFieldMaxValue);
             }
         }
 
         /// <summary>
         /// When the current entry represents a character device or a block device, the minor number is used by the driver to distinguish individual devices it controls.
         /// </summary>
-        /// <remarks>Character and block devices are Unix-specific entry types.</remarks>
+        /// <remarks>Character and block devices are Unix-specific entry types. For PAX entries, setting this property updates the corresponding <c>devminor</c> extended attribute in <see cref="PaxTarEntry.ExtendedAttributes"/>.</remarks>
         /// <exception cref="InvalidOperationException">The entry does not represent a block device or a character device.</exception>
         /// <exception cref="ArgumentOutOfRangeException">The value is negative, or larger than 2097151 when using <see cref="TarEntryFormat.V7"/> or <see cref="TarEntryFormat.Ustar"/>.</exception>
         public int DeviceMinor
@@ -90,32 +91,34 @@ public int DeviceMinor
                 ArgumentOutOfRangeException.ThrowIfNegative(value);
                 if (FormatIsOctalOnly)
                 {
-                    ArgumentOutOfRangeException.ThrowIfGreaterThan(value, 0x1FFFFF); // 7777777 in octal
+                    ArgumentOutOfRangeException.ThrowIfGreaterThan(value, TarHeader.Octal8ByteFieldMaxValue);
                 }
 
                 _header._devMinor = value;
+                _header.SyncNumericExtendedAttribute(TarHeader.PaxEaDevMinor, value, TarHeader.Octal8ByteFieldMaxValue);
             }
         }
 
         /// <summary>
         /// Represents the name of the group that owns this entry.
         /// </summary>
         /// <exception cref="ArgumentNullException">Cannot set a null group name.</exception>
-        /// <remarks><see cref="GroupName"/> is only used in Unix platforms.</remarks>
+        /// <remarks><see cref="GroupName"/> is only used in Unix platforms. For PAX entries, setting this property updates the corresponding <c>gname</c> extended attribute in <see cref="PaxTarEntry.ExtendedAttributes"/>.</remarks>
         public string GroupName
         {
             get => _header._gName ?? string.Empty;
             set
             {
                 ArgumentNullException.ThrowIfNull(value);
                 _header._gName = value;
+                _header.SyncStringExtendedAttribute(TarHeader.PaxEaGName, value, FieldLengths.GName);
             }
         }
 
         /// <summary>
         /// Represents the name of the user that owns this entry.
         /// </summary>
-        /// <remarks><see cref="UserName"/> is only used in Unix platforms.</remarks>
+        /// <remarks><see cref="UserName"/> is only used in Unix platforms. For PAX entries, setting this property updates the corresponding <c>uname</c> extended attribute in <see cref="PaxTarEntry.ExtendedAttributes"/>.</remarks>
         /// <exception cref="ArgumentNullException">Cannot set a null user name.</exception>
         public string UserName
         {
@@ -124,6 +127,7 @@ public string UserName
             {
                 ArgumentNullException.ThrowIfNull(value);
                 _header._uName = value;
+                _header.SyncStringExtendedAttribute(TarHeader.PaxEaUName, value, FieldLengths.UName);
             }
         }
     }

src/libraries/System.Formats.Tar/src/System/Formats/Tar/TarEntry.cs

@@ -84,17 +84,21 @@ internal TarEntry(TarEntry other, TarEntryFormat format)
         /// <summary>
         /// The ID of the group that owns the file represented by this entry.
         /// </summary>
-        /// <remarks>This field is only supported in Unix platforms.</remarks>
+        /// <remarks>This field is only supported in Unix platforms. For PAX entries, setting this property updates the corresponding <c>gid</c> extended attribute in <see cref="PaxTarEntry.ExtendedAttributes"/>.</remarks>
         public int Gid
         {
             get => _header._gid;
-            set => _header._gid = value;
+            set
+            {
+                _header._gid = value;
+                _header.SyncNumericExtendedAttribute(TarHeader.PaxEaGid, value, TarHeader.Octal8ByteFieldMaxValue);
+            }
         }
 
         /// <summary>
         /// A timestamps that represents the last time the contents of the file represented by this entry were modified.
         /// </summary>
-        /// <remarks>In Unix platforms, this timestamp is commonly known as <c>mtime</c>.</remarks>
+        /// <remarks>In Unix platforms, this timestamp is commonly known as <c>mtime</c>. For PAX entries, setting this property updates the corresponding <c>mtime</c> extended attribute in <see cref="PaxTarEntry.ExtendedAttributes"/>.</remarks>
         /// <exception cref="ArgumentOutOfRangeException">The specified value is larger than <see cref="DateTimeOffset.UnixEpoch"/> when using <see cref="TarEntryFormat.V7"/> or <see cref="TarEntryFormat.Ustar"/>.</exception>
         public DateTimeOffset ModificationTime
         {
@@ -106,6 +110,7 @@ public DateTimeOffset ModificationTime
                     ArgumentOutOfRangeException.ThrowIfLessThan(value, DateTimeOffset.UnixEpoch);
                 }
                 _header._mTime = value;
+                _header.SyncTimestampExtendedAttribute(TarHeader.PaxEaMTime, value);
             }
         }
 
@@ -118,6 +123,7 @@ public DateTimeOffset ModificationTime
         /// <summary>
         /// When the <see cref="EntryType"/> indicates a <see cref="TarEntryType.SymbolicLink"/> or a <see cref="TarEntryType.HardLink"/>, this property returns the link target path of such link.
         /// </summary>
+        /// <remarks>For PAX entries, setting this property updates the corresponding <c>linkpath</c> extended attribute in <see cref="PaxTarEntry.ExtendedAttributes"/>.</remarks>
         /// <exception cref="InvalidOperationException">The entry type is not <see cref="TarEntryType.HardLink"/> or <see cref="TarEntryType.SymbolicLink"/>.</exception>
         /// <exception cref="ArgumentNullException">The specified value is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentException">The specified value is empty.</exception>
@@ -132,6 +138,7 @@ public string LinkName
                 }
                 ArgumentException.ThrowIfNullOrEmpty(value);
                 _header._linkName = value;
+                _header.SyncStringExtendedAttribute(TarHeader.PaxEaLinkName, value);
             }
         }
 
@@ -157,24 +164,30 @@ public UnixFileMode Mode
         /// <summary>
         /// Represents the name of the entry, which includes the relative path and the filename.
         /// </summary>
+        /// <remarks>For PAX entries, setting this property updates the corresponding <c>path</c> extended attribute in <see cref="PaxTarEntry.ExtendedAttributes"/>.</remarks>
         public string Name
         {
             get => _header._name;
             set
             {
                 ArgumentException.ThrowIfNullOrEmpty(value);
                 _header._name = value;
+                _header.SyncStringExtendedAttribute(TarHeader.PaxEaName, value);
             }
         }
 
         /// <summary>
         /// The ID of the user that owns the file represented by this entry.
         /// </summary>
-        /// <remarks>This field is only supported in Unix platforms.</remarks>
+        /// <remarks>This field is only supported in Unix platforms. For PAX entries, setting this property updates the corresponding <c>uid</c> extended attribute in <see cref="PaxTarEntry.ExtendedAttributes"/>.</remarks>
         public int Uid
         {
             get => _header._uid;
-            set => _header._uid = value;
+            set
+            {
+                _header._uid = value;
+                _header.SyncNumericExtendedAttribute(TarHeader.PaxEaUid, value, TarHeader.Octal8ByteFieldMaxValue);
+            }
         }
 
         /// <summary>
@@ -591,10 +604,10 @@ private FileStreamOptions CreateFileStreamOptions(bool isAsync)
 
             if (!OperatingSystem.IsWindows())
             {
-                 const UnixFileMode OwnershipPermissions =
-                    UnixFileMode.UserRead | UnixFileMode.UserWrite | UnixFileMode.UserExecute |
-                    UnixFileMode.GroupRead | UnixFileMode.GroupWrite | UnixFileMode.GroupExecute |
-                    UnixFileMode.OtherRead | UnixFileMode.OtherWrite |  UnixFileMode.OtherExecute;
+                const UnixFileMode OwnershipPermissions =
+                   UnixFileMode.UserRead | UnixFileMode.UserWrite | UnixFileMode.UserExecute |
+                   UnixFileMode.GroupRead | UnixFileMode.GroupWrite | UnixFileMode.GroupExecute |
+                   UnixFileMode.OtherRead | UnixFileMode.OtherWrite | UnixFileMode.OtherExecute;
 
                 // Restore permissions.
                 // For security, limit to ownership permissions, and respect umask (through UnixCreateMode).

src/libraries/System.Formats.Tar/src/System/Formats/Tar/TarHeader.Read.cs

@@ -103,16 +103,24 @@ internal sealed partial class TarHeader
         // If any of the dictionary entries use the name of a standard attribute, that attribute's value gets replaced with the one from the dictionary.
         // Unlike the historic header, numeric values in extended attributes are stored using decimal, not octal.
         // Throws if any conversion from string to the expected data type fails.
-        internal void ReplaceNormalAttributesWithExtended(Dictionary<string, string>? dictionaryFromExtendedAttributesHeader)
+        internal void ReplaceNormalAttributesWithExtended(IEnumerable<KeyValuePair<string, string>>? extendedAttributes)
         {
-            if (dictionaryFromExtendedAttributesHeader == null || dictionaryFromExtendedAttributesHeader.Count == 0)
+            if (extendedAttributes == null)
             {
                 return;
             }
 
-            AddExtendedAttributes(dictionaryFromExtendedAttributesHeader);
+            AddExtendedAttributes(extendedAttributes);
 
-            // Find all the extended attributes with known names and save them in the expected standard attribute.
+            if (_ea == null || _ea.Count == 0)
+            {
+                // no extended attributes were added, so we can skip the rest of the processing
+                return;
+            }
+
+            // Find all the extended attributes with known names and save them
+            // in the expected standard attribute. Extended attributes are preserved
+            // as-is to avoid data loss during roundtripping.
 
             // The 'name' header field only fits 100 bytes, so we always store the full name text to the dictionary.
             if (ExtendedAttributes.TryGetValue(PaxEaName, out string? paxEaName))
@@ -121,7 +129,9 @@ internal void ReplaceNormalAttributesWithExtended(Dictionary<string, string>? di
             }
 
             // The 'linkName' header field only fits 100 bytes, so we always store the full linkName text to the dictionary.
-            if (ExtendedAttributes.TryGetValue(PaxEaLinkName, out string? paxEaLinkName))
+            // Only apply to link entries to avoid setting _linkName on non-link entry types.
+            if (_typeFlag is TarEntryType.HardLink or TarEntryType.SymbolicLink &&
+                ExtendedAttributes.TryGetValue(PaxEaLinkName, out string? paxEaLinkName))
             {
                 _linkName = paxEaLinkName;
             }