ui: use "procutil.shellsplit" to parse command A commandline containing a space ('"C:\\Program Files\\bar.exe" "..."') must not simply split at whitespace, instead quoting has to be taken into account. Use "shlex.split()" to parse it instead. This can improve the error message if we fail to launch a user configured editor which does not exist. Consider [ui] editor = "C:\Program Files\editor\editor.exe" where the path does not exist. "hg histedit" currently aborts with > Abort: edit failed: Program exited with status 1 here "Program" is not part of the message but the name of the program that failed (i.e. `basename("C:\\Program ")`). With this change the message instead reads > Abort: edit failed: C:\Program Files\editor\editor.exe exited with > status 1 which is also not ideal since infact "cmd.exe" exited with code 1, not the editor. But the real error message ("File not found") gets swallowed by `procutil` and including the correct path improves the error message nevertheless.

cext: move variable declaration to the top of the block for C89 support Not sure if we still care about C89 in general, but MSVC requires this style too. Differential Revision: https://phab.mercurial-scm.org/D8304

phabricator: allow multiple DREVSPEC args to phabread|phabimport|phabupdate Per Augie's request. Like regular revsets, the result is the union of all given specs. Unlike regular revsets, these don't resolve in parent -> child order, and should be specified as such on the command line. This change invalidated a previous test using an empty `hg phabread`, so it has been switched to `hg debugcallconduit` to preserve that coverage. Differential Revision: https://phab.mercurial-scm.org/D8233

phabricator: add a helper function to convert DREVSPECs to a DREV dict list Prep work for allowing multiple DREVSPECs to various commands, and properly validating the input. Differential Revision: https://phab.mercurial-scm.org/D8232