Investigating Emacs startup failure

[Richard Copley]

There's something wrong with my Emacs installation (master, on Windows).
When invoked normally, it fails to start. Since I last successfully ran
Emacs in this way, I have pulled from master and rebuilt, and updated my
ELPA packages.

I don't know how to debug this, so I don't know if a bug report is needed,
and if so, what to put in it. Does anyone have any suggestions? Here is
what I have already tried:

* Invoked in my customary fashion as "runemacs" from a start-menu shortcut,
the process exits immediately without displaying a frame. The same if
invoked as "runemacs" from the command line.

* Invoked as "emacs" or "emacs --debug-init" from the command line, it
writes a message:

  GPG error: "no usable configuration", OpenPGP

and exits, with exit status -1. (I don't know whether the GPG error and the
failure to start are related. I usually launch runemacs from the start
menu, so if this message was being printed before, I wouldn't have seen the
error.)

* Invoked as "emacs -Q", it starts as expected. Having done that, I can
load my init file with M-x load-file, and then everything looks normal (and
there are no messages or errors).

* Invoked as "gdb -batch -quiet -ex "set auto-load safe-path /" -ex run -ex
quit --args ./emacs.exe", it prints the following (note:
"add-auto-load-safe-path C:\projects\emacs\src\.gdbinit" is already present
in my .gdbinit, which is copied to all the "$HOME" directories I can think
of: the correct one %APPDATA%, %LOCALAPPDATA%, %HOMEPATH% and the MSYS2
home directory):

C:\projects\emacs\src>gdb -batch -quiet -ex run -ex quit --args ./emacs.exe
warning: File "C:\projects\emacs\src\.gdbinit" auto-loading has been
declined by your `auto-load safe-path' set to
"$debugdir:$datadir/auto-load".
To enable execution of this file add
        add-auto-load-safe-path C:\projects\emacs\src\.gdbinit
line to your configuration file "$HOME/.gdbinit".
To completely disable this security protection add
        set auto-load safe-path /
line to your configuration file "$HOME/.gdbinit".
For more information about this security protection see the
"Auto-loading safe path" section in the GDB manual.  E.g., run from the
shell:
        info "(gdb)Auto-loading safe path"
[New Thread 14644.0x1b8]
[New Thread 14644.0x1738]
[New Thread 14644.0x428c]
[New Thread 14644.0x35d0]
[New Thread 14644.0x350c]
[New Thread 14644.0x2a7c]
[Thread 14644.0x2a7c exited with code 1]
[New Thread 14644.0x211c]
[Thread 14644.0x211c exited with code 1]
Gwarning: G
Pwarning: P
Gwarning: G
 warning:
ewarning: e
rwarning: r
rwarning: r
owarning: o
rwarning: r
:warning: :
 warning:
"warning: "
nwarning: n
owarning: o
 warning:
uwarning: u
swarning: s
awarning: a
bwarning: b
lwarning: l
ewarning: e
 warning:
cwarning: c
owarning: o
nwarning: n
fwarning: f
iwarning: i
gwarning: g
uwarning: u
rwarning: r
awarning: a
twarning: t
iwarning: i
owarning: o
nwarning: n
"warning: "
,warning: ,
 warning:
Owarning: O
pwarning: p
ewarning: e
nwarning: n
Pwarning: P
Gwarning: G
Pwarning: P

warning:
[Thread 14644.0x350c exited with code 0]
[Thread 14644.0x35d0 exited with code 4294967295]
[Thread 14644.0x428c exited with code 4294967295]
[Thread 14644.0x1738 exited with code 4294967295]
[Inferior 1 (process 14644) exited with code 037777777777]