diff mercurial/help/config.txt @ 22158:bc2132dfc0a4

alias: expand "$@" as list of parameters quoted individually (BC) (issue4200)

Before this patch, there was no way to pass in all the positional parameters as
separate words down to another command.

(1) $@ (without quotes) would expand to all the parameters separated by a space.
    This would work fine for arguments without spaces, but arguments with spaces
    in them would be split up by POSIX shells into separate words.
(2) '$@' (in single quotes) would expand to all the parameters within a pair of
    single quotes. POSIX shells would then treat the entire list of arguments
    as one word.
(3) "$@" (in double quotes) would expand similarly to (2).

With this patch, we expand "$@" (in double quotes) as all positional
parameters, quoted individually with util.shellquote, and separated by spaces.
Under standard field-splitting conditions, POSIX shells will tokenize each
argument into exactly one word.

This is a backwards-incompatible change, but the old behavior was arguably a
bug: Bourne-derived shells have expanded "$@" as a tokenized list of positional
parameters for a very long time. I could find this behavior specified in IEEE
Std 1003.1-2001, and this probably goes back to much further before that.

--- a/mercurial/help/config.txt	Wed Aug 13 22:37:09 2014 -0700
+++ b/mercurial/help/config.txt	Wed Aug 13 23:21:52 2014 -0700
@@ -229,8 +229,9 @@
 Positional arguments like ``$1``, ``$2``, etc. in the alias definition
 expand to the command arguments. Unmatched arguments are
 removed. ``$0`` expands to the alias name and ``$@`` expands to all
-arguments separated by a space. These expansions happen before the
-command is passed to the shell.
+arguments separated by a space. ``"$@"`` (with quotes) expands to all
+arguments quoted individually and separated by a space. These expansions
+happen before the command is passed to the shell.
 
 Shell aliases are executed in an environment where ``$HG`` expands to
 the path of the Mercurial that was used to execute the alias. This is