tempname: add parent and cleanup arguments

NEWS.md

@@ -21,6 +21,8 @@ New library functions
 ---------------------
 
 * The `splitpath` function now accepts any `AbstractString` whereas previously it only accepted paths of type `String` ([#33012]).
+* The `tempname` function now takes an optional `parent::AbstractString` argument to give it a directory in which to attempt to produce a temporary path name ([#33090]).
+* The `tempname` function now takes a `cleanup::Bool` keyword argument defaulting to `true`, which causes the process to try to ensure that any file or directory at the path returned by `tempname` is deleted upon process exit ([#33090]).
 
 
 Standard library changes

base/file.jl

@@ -500,29 +500,32 @@ function mktemp(parent::AbstractString=tempdir(); cleanup::Bool=true)
     return (filename, Base.open(filename, "r+"))
 end
 
-function tempname()
-    parent = tempdir()
+function tempname(parent::AbstractString=tempdir(); cleanup::Bool=true)
+    isdir(parent) || throw(ArgumentError("$(repr(parent)) is not a directory"))
     seed::UInt32 = rand(UInt32)
     while true
         if (seed & typemax(UInt16)) == 0
             seed += 1
         end
         filename = _win_tempname(parent, seed)
         if !ispath(filename)
+            cleanup && temp_cleanup_later(filename)
             return filename
         end
         seed += 1
     end
 end
 
 else # !windows
+
 # Obtain a temporary filename.
-function tempname()
-    d = tempdir() # tempnam ignores TMPDIR on darwin
-    p = ccall(:tempnam, Cstring, (Cstring, Cstring), d, temp_prefix)
+function tempname(parent::AbstractString=tempdir(); cleanup::Bool=true)
+    isdir(parent) || throw(ArgumentError("$(repr(parent)) is not a directory"))
+    p = ccall(:tempnam, Cstring, (Cstring, Cstring), parent, temp_prefix)
     systemerror(:tempnam, p == C_NULL)
     s = unsafe_string(p)
     Libc.free(p)
+    cleanup && temp_cleanup_later(s)
     return s
 end
 
@@ -540,16 +543,35 @@ end # os-test
 
 
 """
-    tempname()
+    tempname(parent=tempdir(); cleanup=true) -> String
 
 Generate a temporary file path. This function only returns a path; no file is
-created. The path is likely to be unique, but this cannot be guaranteed.
+created. The path is likely to be unique, but this cannot be guaranteed due to
+the very remote posibility of two simultaneous calls to `tempname` generating
+the same file name. The name is guaranteed to differ from all files already
+existing at the time of the call to `tempname`.
+
+When called with no arguments, the temporary name will be an absolute path to a
+temporary name in the system temporary directory as given by `tempdir()`. If a
+`parent` directory argument is given, the temporary path will be in that
+directory instead.
+
+The `cleanup` option controls whether the process attempts to delete the
+returned path automatically when the process exits. Note that the `tempname`
+function does not create any file or directory at the returned location, so
+there is nothing to cleanup unless you create a file or directory there. If
+you do and `clean` is `true` it will be deleted upon process termination.
+
+!!! compat "Julia 1.4"
+    The `parent` and `cleanup` arguments were added in 1.4. Prior to Julia 1.4
+    the path `tempname` would never be cleaned up at process termination.
 
 !!! warning
 
     This can lead to security holes if another process obtains the same
     file name and creates the file before you are able to. Open the file with
-    `JL_O_EXCL` if this is a concern. Using [`mktemp()`](@ref) is also recommended instead.
+    `JL_O_EXCL` if this is a concern. Using [`mktemp()`](@ref) is also
+    recommended instead.
 """
 tempname()
 

test/file.jl

@@ -48,6 +48,18 @@ if !Sys.iswindows()
     cd(pwd_)
 end
 
+using Random
+
+@testset "tempname with parent" begin
+    t = tempname()
+    @test dirname(t) == tempdir()
+    mktempdir() do d
+        t = tempname(d)
+        @test dirname(t) == d
+    end
+    @test_throws ArgumentError tempname(randstring())
+end
+
 child_eval(code::String) = eval(Meta.parse(readchomp(`$(Base.julia_cmd()) -E $code`)))
 
 @testset "mktemp/dir basic cleanup" begin
@@ -67,6 +79,14 @@ child_eval(code::String) = eval(Meta.parse(readchomp(`$(Base.julia_cmd()) -E $co
     # mktempdir with cleanup
     t = child_eval("t = mktempdir(); touch(joinpath(t, \"file.txt\")); t")
     @test !ispath(t)
+    # tempname without cleanup
+    t = child_eval("t = tempname(cleanup=false); touch(t); t")
+    @test isfile(t)
+    rm(t, force=true)
+    @test !ispath(t)
+    # tempname with cleanup
+    t = child_eval("t = tempname(); touch(t); t")
+    @test !ispath(t)
 end
 
 import Base.Filesystem: TEMP_CLEANUP_MIN, TEMP_CLEANUP_MAX, TEMP_CLEANUP