Add REPL completion for tilde paths (JuliaLang#23475)

Overrides path completions if a user expansion is available. For
example, `~/Docu` will autocomplete to `/home/user/Docu` after one
<TAB>, and then to `/home/user/Documents` after a second <TAB>.

base/repl/REPLCompletions.jl

@@ -194,6 +194,11 @@ function complete_path(path::AbstractString, pos; use_envpath=false)
  return matchList, startpos:pos, !isempty(matchList)
 end
 
+function complete_expanduser(path::AbstractString, r)
+ expanded = expanduser(path)
+ return String[expanded], r, path != expanded
+end
+
 # Determines whether method_complete should be tried. It should only be done if
 # the string endswiths ',' or '(' when disregarding whitespace_chars
 function should_method_complete(s::AbstractString)
@@ -470,13 +475,19 @@ function completions(string, pos)
  m = match(r"[\t\n\r\"><=*?|]| (?!\\)", reverse(partial))
  startpos = nextind(partial, reverseind(partial, m.offset))
  r = startpos:pos
+
+ expanded = complete_expanduser(replace(string[r], r"\\ ", " "), r)
+ expanded[3] && return expanded # If user expansion available, return it
+
  paths, r, success = complete_path(replace(string[r], r"\\ ", " "), pos)
+
  if inc_tag == :string &&
  length(paths) == 1 && # Only close if there's a single choice,
  !isdir(expanduser(replace(string[startpos:start(r)-1] * paths[1], r"\\ ", " "))) && # except if it's a directory
  (length(string) <= pos || string[pos+1] != '"') # or there's already a " at the cursor.
  paths[1] *= "\""
  end
+
  #Latex symbols can be completed for strings
  (success || inc_tag==:cmd) && return sort!(paths), r, success
  end

test/replcompletions.jl

@@ -574,10 +574,11 @@ if Sys.isunix()
  path = homedir()
  dir = joinpath(path, "tmpfoobar")
  mkdir(dir)
- s = "\"~/tmpfoob"
+ s = "\"" * path * "/tmpfoob"
  c,r = test_complete(s)
  @test "tmpfoobar/" in c
- @test r == 4:10
+ l = 3 + length(path)
+ @test r == l:l+6
  @test s[r] == "tmpfoob"
  s = "\"~"
  @test "tmpfoobar/" in c
@@ -684,6 +685,18 @@ let #test that it can auto complete with spaces in file/path
  rm(dir, recursive=true)
 end
 
+let # Test tilde path completion
+ c, r, res = test_complete("\"~/julia")
+ if !Sys.iswindows()
+ @test res && c == String[homedir() * "/julia"]
+ else
+ @test !res
+ end
+
+ c, r, res = test_complete("\"foo~bar")
+ @test !res
+end
+
 # Test the completion returns nothing when the folder do not exist
 c,r = test_complete("cd(\"folder_do_not_exist_77/file")
 @test length(c) == 0