#
#
# delete "tests/log_quits_on_SIGPIPE/hookfile"
# 
# patch "tests/log_quits_on_SIGPIPE/__driver__.lua"
#  from [516da7ffcbf62fcbe923784a6a1d11bedbb553e2]
#    to [058dba7d455d1d84269b4f9e884775d2ef4dac13]
#
============================================================
--- tests/log_quits_on_SIGPIPE/__driver__.lua	516da7ffcbf62fcbe923784a6a1d11bedbb553e2
+++ tests/log_quits_on_SIGPIPE/__driver__.lua	058dba7d455d1d84269b4f9e884775d2ef4dac13
@@ -6,73 +6,78 @@ SIGPIPE = 13 -- what it is on traditiona
 skip_if(ostype=="Windows")
 SIGPIPE = 13 -- what it is on traditional Unixy systems
 
-mtn_setup()
-addfile("file", "This is a file")
-commit()
-
 -- Testing this correctly involves avoiding a number of race
--- conditions.  This is how we used to try to do it:
+-- conditions.  This is the behavior we want:
 --
 --    parent               child
 --    ------               -----
 --    fork
 --                         exec
---                         open pipe for write
---    kill(child, SIGPIPE)
---
--- But it is entirely possible for the parent to complete all of the
--- actions on its side before the child has set up signal handlers,
--- and SIGPIPE may be being ignored, so the signal gets lost.  Also,
--- this is not really testing what we want to test, which is behavior
--- on delivery of a real SIGPIPE by the kernel.  So we want to do this
--- instead:
---
---    parent               child
---    ------               -----
---    fork
---                         exec
---                         open pipe for write
---    open pipe for read
+--    open pipe for read   open pipe for write
+--                         write to pipe, which blocks
 --    close pipe
---                         write to pipe
 --                         (kernel generates SIGPIPE)
 --
--- There is a synchronization point at the open()s, but the child may
--- still do the write before the parent closes its end of the pipe,
--- causing the signal not to be delivered.  To handle this, we need
--- to introduce a second pipe to use as a semaphore:
+-- There is a synchronization point at the open()s, but it is
+-- essential to ensure that the child's write operation fills the
+-- kernel's pipe buffer and blocks.  If we did not fill the pipe
+-- buffer, the write could complete and return before the parent
+-- closes its end of the pipe, causing the signal not to be delivered.
 --
---    parent               child
---    ------               -----
---    fork
---                         exec
---                         open p1 for write
---    open p1 for read
---                         open p2 for write
---    close p1
---    open p2 for read
---                         write to p1
---                         (kernel generates SIGPIPE)
+-- Kernel pipe buffers are known to be as big as 64K.  Thus, it is
+-- overkill to make four commits each with an 64K log message, but I
+-- like me some overkill.  (There is a temptation to make it sixteen;
+-- I can imagine someone deciding to bulk up the pipe buffer to a nice
+-- round megabyte.  But the time this test takes is proportional to
+-- the number of commits, so I won't.  I tried having a bigger log
+-- message but that crashed "mtn commit".)
 --
--- It does not matter which side opens p2 for read and which for
--- write, so we have each process open both pipes the same way.
--- The code for the child half of this is in "hookfile".
---
--- Note that if we ever get the ability to redirect stdout in bg(),
--- then we should point it at p1, and have hookfile just synchronize
--- with p2; this tests even more closely the case we care about.
+-- The following 1024-byte block of nonsense is courtesy of the Eater
+-- of Meaning.
 
-check({"mkfifo", "fifo1"}, 0)
-check({"mkfifo", "fifo2"}, 0)
-check(get("hookfile"))
+message = [[
+Won whip he keel, dens canal ply chafe hoots tooler gad nut pal hew
+visa. Area dunn felts morrow exxon bib bern oz toil clot knightsbridge
+malta tex organs. Respect, aft beehive, dip i mitchell walrus en BELY
+Stow 5 pot juice 79 oberon preamble io Arabian, stag timers loy son
+Paws fat i ram suez wiper, den ron unix minaret wire po fox sicilian
+nubia puss fight. Oz sweeneys be mckee on paving eyers, em eel a
+johnny thumbed illegal sash do ku 8,296 jazz, margo or rib ah fess
+swine so vat up timeouts. Us drop fed hip beds ha i meaner (ax todays
+suez of withdraw 53 electrify) dim en ah listings-cinnamon ad minded
+Anu races nod abui a abide.
 
-proc = bg(mtn("log", "--rcfile=hookfile"), -SIGPIPE, true, true)
+Epaulet if brisker de carnivals mae ed civic lettering alfa ale pandas
+(micaa pry ada zoo pale or opt Tax Shy Slowed incapable), wee hem
+bernoulli ott ha harlem he malabar sir Roach cortex ash avouch as Soda
+Jimi. Ohm thief ox bay loops shaves gobi nu pi reese-ax-roe-waging
+vieti salable bin love soft all oz oboe plush sniffed rowdy em
+asserting used en sit ham land nat fly.
+]]
 
-p1, e1 = io.open("fifo1", "r")
-if p1 == nil then err(e1) end
-p1:close()
-p2, e2 = io.open("fifo2", "r")
-if p2 == nil then err(e2) end
-p2:close()
+for i = 1,6 do
+   message = message .. message
+end
 
+mtn_setup()
+addfile("file", "fnord")
+for i = 1,4 do
+   writefile("file", "commit "..tonumber(i).."\n")
+   commit(nil, message)
+end
+
+check({"mkfifo", "fifo"}, 0, nil, nil)
+
+-- We do this crazy thing because bg() can't redirect stdout.
+-- FIXME: It should be able to redirect stdout.
+-- FIXME: The quoting here will break if any of the strings
+--        produced by mtn() contains a single quote.
+
+logcmd = "exec '" .. table.concat(mtn("log", "--no-graph"), "' '") .. "' >fifo"
+
+proc = bg({"/bin/sh", "-c", logcmd}, -SIGPIPE, nil, false)
+
+p, e = io.open("fifo", "r")
+if p == nil then err(e) end
+p:close()
 proc:finish(3) -- three second timeout