fix(dir.rmtree) remove symlinks without following

CHANGELOG.md

@@ -12,7 +12,10 @@ see [CONTRIBUTING.md](CONTRIBUTING.md#release-instructions-for-a-new-version) fo
    [#360](https://github.com/lunarmodules/Penlight/pull/360)
  - feat: `permute.list_table` generate table with different sets of values
    [#360](https://github.com/lunarmodules/Penlight/pull/360)
- - feat: deprecation functionality `utils.raise_deprecation` [#361](https://github.com/lunarmodules/Penlight/pull/361)
+ - feat: deprecation functionality `utils.raise_deprecation`
+   [#361](https://github.com/lunarmodules/Penlight/pull/361)
+ - fix: `dir.rmtree` failed to remove symlinks to directories
+   [#365](https://github.com/lunarmodules/Penlight/pull/365)
 
 
 ## 1.9.1 (2020-09-27)

lua/pl/dir.lua

@@ -317,20 +317,34 @@ function dir.walk(root,bottom_up,follow_links)
 end
 
 --- remove a whole directory tree.
--- @string fullpath A directory path
+-- Symlinks in the tree will be deleted without following them.
+-- @string fullpath A directory path (must be an actual directory, not a symlink)
 -- @return true or nil
 -- @return error if failed
 -- @raise fullpath must be a string
 function dir.rmtree(fullpath)
     assert_dir(1,fullpath)
     if path.islink(fullpath) then return false,'will not follow symlink' end
     for root,dirs,files in dir.walk(fullpath,true) do
-        for i,f in ipairs(files) do
-            local res, err = remove(path.join(root,f))
-            if not res then return nil,err end
+        if path.islink(root) then
+            -- sub dir is a link, remove link, do not follow
+            if is_windows then
+                -- Windows requires using "rmdir". Deleting the link like a file
+                -- will instead delete all files from the target directory!!
+                local res, err = rmdir(root)
+                if not res then return nil,err .. ": " .. root end
+            else
+                local res, err = remove(root)
+                if not res then return nil,err .. ": " .. root end
+            end
+        else
+            for i,f in ipairs(files) do
+                local res, err = remove(path.join(root,f))
+                if not res then return nil,err .. ": " .. path.join(root,f) end
+            end
+            local res, err = rmdir(root)
+            if not res then return nil,err .. ": " .. root end
         end
-        local res, err = rmdir(root)
-        if not res then return nil,err end
     end
     return true
 end

tests/test-dir.lua

@@ -4,6 +4,7 @@ local dir = require( "pl.dir" )
 local file = require( "pl.file" )
 local path = require( "pl.path" )
 local asserteq = require( "pl.test" ).asserteq
+local lfs = require("lfs")
 
 asserteq(dir.fnmatch("foobar", "foo*bar"), true)
 asserteq(dir.fnmatch("afoobar", "foo*bar"), false)
@@ -156,6 +157,45 @@ file.delete( newFileName )
 
 
 
+-- Test rmtree -----------------------------------------
+do
+  local dirName = path.tmpname()
+  os.remove(dirName)
+  assert(dir.makepath(dirName))
+  assert(file.write(path.normpath(dirName .. "/file_base.txt"), "hello world"))
+  assert(dir.makepath(path.normpath(dirName .. "/sub1")))
+  assert(file.write(path.normpath(dirName .. "/sub1/file_sub1.txt"), "hello world"))
+  assert(dir.makepath(path.normpath(dirName .. "/sub2")))
+  assert(file.write(path.normpath(dirName .. "/sub2/file_sub2.txt"), "hello world"))
+
+
+  local linkTarget = path.tmpname()
+  os.remove(linkTarget)
+  assert(dir.makepath(linkTarget))
+  local linkFile = path.normpath(linkTarget .. "/file.txt")
+  assert(file.write(linkFile, "hello world"))
+
+  local linkSource = path.normpath(dirName .. "/link1")
+  assert(lfs.link(linkTarget, linkSource, true))
+
+  -- test: rmtree will not follow symlinks
+  local ok, err = dir.rmtree(linkSource)
+  asserteq(ok, false)
+  asserteq(err, "will not follow symlink")
+
+  -- test: rmtree removes a tree without following symlinks in that tree
+  local ok, err = dir.rmtree(dirName)
+  asserteq(err, nil)
+  asserteq(ok, true)
+
+  asserteq(path.exists(dirName), false)  -- tree is gone, including symlink
+  assert(path.exists(linkFile), "expected linked-to file to still exist")  -- symlink target file is still there
+
+  -- cleanup
+  assert(dir.rmtree(linkTarget))
+end
+
+
 -- have NO idea why forcing the return code is necessary here (Windows 7 64-bit)
 os.exit(0)