Merge branch 'jk/epipe-in-async'

Handling of errors while writing into our internal asynchronous
process has been made more robust, which reduces flakiness in our
tests.

* jk/epipe-in-async:
  t5504: handle expected output from SIGPIPE death
  test_must_fail: report number of unexpected signal
  fetch-pack: ignore SIGPIPE in sideband demuxer
  write_or_die: handle EPIPE in async threads

diff --cc run-command.c
Simple merge

diff --cc run-command.h
index d5a57f922781de57d8ee6ae56f90af1456ccd5d5,c0969c7695f6b550b382b5704ceb9b2c23b3e3e0..42917e8618ea469ff56d52704794b6e3bc86cf97
--- 1/run-command.h
--- 2/run-command.h
+++ b/run-command.h
@@@ -121,85 -121,6 +121,86 @@@ struct async 
  int start_async(struct async *async);
  int finish_async(struct async *async);
  int in_async(void);
+ void NORETURN async_exit(int code);
  
 +/**
 + * This callback should initialize the child process and preload the
 + * error channel if desired. The preloading of is useful if you want to
 + * have a message printed directly before the output of the child process.
 + * pp_cb is the callback cookie as passed to run_processes_parallel.
 + * You can store a child process specific callback cookie in pp_task_cb.
 + *
 + * Even after returning 0 to indicate that there are no more processes,
 + * this function will be called again until there are no more running
 + * child processes.
 + *
 + * Return 1 if the next child is ready to run.
 + * Return 0 if there are currently no more tasks to be processed.
 + * To send a signal to other child processes for abortion,
 + * return the negative signal number.
 + */
 +typedef int (*get_next_task_fn)(struct child_process *cp,
 +                              struct strbuf *err,
 +                              void *pp_cb,
 +                              void **pp_task_cb);
 +
 +/**
 + * This callback is called whenever there are problems starting
 + * a new process.
 + *
 + * You must not write to stdout or stderr in this function. Add your
 + * message to the strbuf err instead, which will be printed without
 + * messing up the output of the other parallel processes.
 + *
 + * pp_cb is the callback cookie as passed into run_processes_parallel,
 + * pp_task_cb is the callback cookie as passed into get_next_task_fn.
 + *
 + * Return 0 to continue the parallel processing. To abort return non zero.
 + * To send a signal to other child processes for abortion, return
 + * the negative signal number.
 + */
 +typedef int (*start_failure_fn)(struct child_process *cp,
 +                              struct strbuf *err,
 +                              void *pp_cb,
 +                              void *pp_task_cb);
 +
 +/**
 + * This callback is called on every child process that finished processing.
 + *
 + * You must not write to stdout or stderr in this function. Add your
 + * message to the strbuf err instead, which will be printed without
 + * messing up the output of the other parallel processes.
 + *
 + * pp_cb is the callback cookie as passed into run_processes_parallel,
 + * pp_task_cb is the callback cookie as passed into get_next_task_fn.
 + *
 + * Return 0 to continue the parallel processing.  To abort return non zero.
 + * To send a signal to other child processes for abortion, return
 + * the negative signal number.
 + */
 +typedef int (*task_finished_fn)(int result,
 +                              struct child_process *cp,
 +                              struct strbuf *err,
 +                              void *pp_cb,
 +                              void *pp_task_cb);
 +
 +/**
 + * Runs up to n processes at the same time. Whenever a process can be
 + * started, the callback get_next_task_fn is called to obtain the data
 + * required to start another child process.
 + *
 + * The children started via this function run in parallel. Their output
 + * (both stdout and stderr) is routed to stderr in a manner that output
 + * from different tasks does not interleave.
 + *
 + * If start_failure_fn or task_finished_fn are NULL, default handlers
 + * will be used. The default handlers will print an error message on
 + * error without issuing an emergency stop.
 + */
 +int run_processes_parallel(int n,
 +                         get_next_task_fn,
 +                         start_failure_fn,
 +                         task_finished_fn,
 +                         void *pp_cb);
 +
  #endif