Tar.create: include entries for all directories

README.md

@@ -293,14 +293,6 @@ and it still records user and group information, modification times and exact
 permissions. Coaxing command-line `tar` programs to omit this non-portable
 information and use a portable (and `git`-compatible sort order) is non-trivial.
 
-Another difference from command-line `tar`: non-empty directories are also
-omitted from the tarballs that `Tar` creates since no metadata is recorded about
-directories aside from the fact that they exist and the existence of non-empty
-directories is already implied by the fact that they contain something else. If,
-in the future, the ability to record metadata about directories is added,
-tarballs will record entries for non-empty directories with non-default
-metadata.
-
 On the extraction side of things, doing `Tar.extract(tarball, dir)` is roughly
 equivalent to the following commands:
 ```sh
@@ -472,6 +464,15 @@ have the same `git` tree hash, but produce different tarballs. Two _identical_
 file trees will always produce identical tarballs, however, and that tarball
 should remain stable in future versions of the `Tar` package.
 
+**Note:** the canonical tarball format was [changed] slightly in the 1.10
+release of the package. Since that release, the canonical format _includes_ all
+directories in the canonical tarball format, whereas previously non-empty
+directories were omitted since their existence is implied by their contents. The
+absence of explicit directory entries in tarballs confused some external
+tooling, so it was deemed worth a small format change to avoid such problems.
+
+[changed]: https://github.com/JuliaIO/Tar.jl/pull/106
+
 The `tree_hash` function can be used to compute a git-style tree hash of the
 contents of a tarball (without needing to extract it). Moreover, two tarballs
 created by the `Tar` package will have the same hash if and only if they contain

src/create.jl

@@ -80,24 +80,26 @@ function write_tarball(
     tar_path::String = ".";
     buf::Vector{UInt8} = Vector{UInt8}(undef, DEFAULT_BUFFER_SIZE),
 )
-    w = 0
     hdr, data = callback(sys_path, tar_path)
     if hdr.type == :directory
         data isa Union{Nothing, AbstractDict{<:AbstractString}} ||
             error("callback must return a dict of strings, got: $(repr(data))")
-        data !== nothing && for name in sort!(collect(keys(data)))
-            sys_path′ = data[name]
-            tar_path′ = tar_path == "." ? name : "$tar_path/$name"
-            w += write_tarball(callback, tar, sys_path′, tar_path′, buf=buf)
-        end
     else
         data isa Union{Nothing, AbstractString, IO, Tuple{IO,Integer}} ||
             error("callback must return nothing, string or IO, got: $(repr(data))")
     end
-    if hdr.type != :directory || w == 0
+    w = 0
+    if tar_path != "."
+        w += write_tarball(tar, hdr, data, buf=buf)
+    end
+    data isa AbstractDict && for name in sort!(collect(keys(data)))
+        sys_path′ = data[name]
+        tar_path′ = tar_path == "." ? name : "$tar_path/$name"
+        w += write_tarball(callback, tar, sys_path′, tar_path′, buf=buf)
+    end
+    if tar_path == "." && w == 0
         w += write_tarball(tar, hdr, data, buf=buf)
     end
-    @assert w > 0
     return w
 end
 

test/runtests.jl

@@ -212,6 +212,7 @@ end
     # check rewrite
     tarball′ = Tar.rewrite(tarball)
     @test Tar.list(tarball′) == [
+        Tar.Header("dir", :directory, 0o755, 0, "")
         Tar.Header("dir/file", :file, 0o755, 0, "")
         Tar.Header("file", :file, 0o755, 0, "")
     ]

test/setup.jl

@@ -135,7 +135,7 @@ function make_test_dir(gen_skip::Bool=false)
     return dir
 end
 
-const test_dir_paths = ["dir/file", "empty", "file", "link"]
+const test_dir_paths = ["dir", "dir/file", "empty", "file", "link"]
 Sys.iswindows() && pop!(test_dir_paths)
 
 # uses Tar.list(callback, tarball) API