Subject: [PATCH v2 0/5] pager: test for exit behavior & trace2 bug fix

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Tue, 2 Feb 2021 02:59:56 +0100

A v2 with better tests and some misc adjustments. As noted in v1 1-4
are just adding better test coverage for behavior we already have, and
fixing a small bug in trace2 output.

The 5/5 is a WIP start at respecting the pager's exit code and
ignoring the SIGPIPE. Junio had a suggestion to do that in
<[email-masked]>, but as seen & noted there
it's quite a bit more complex when we have to deal with the atexit
sibling function.

Ævar Arnfjörð Bjarmason (5):
  pager: refactor wait_for_pager() function
  pager: test for exit code with and without SIGPIPE
  run-command: add braces for "if" block in wait_or_whine()
  pager: properly log pager exit code when signalled
  WIP pager: respect exit code of pager over SIGPIPE

 pager.c          |  24 +++++----
 run-command.c    |   7 ++-
 t/t7006-pager.sh | 130 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 148 insertions(+), 13 deletions(-)

Range-diff:
2:  6509ae44751 = 1:  aab89cc8619 pager: refactor wait_for_pager() function
1:  cba284dcf55 ! 2:  edf513bb174 pager: test for exit code
    @@ Metadata
     Author: Ævar Arnfjörð Bjarmason <[email-masked]>
     
      ## Commit message ##
    -    pager: test for exit code
    +    pager: test for exit code with and without SIGPIPE
     
         Add tests for how git behaves when the pager itself exits with
         non-zero, as well as for us exiting with 141 when we're killed with
    @@ Commit message
         current behavior.
     
         This test construct is stolen from 7559a1be8a0 (unblock and unignore
    -    SIGPIPE, 2014-09-18).
    +    SIGPIPE, 2014-09-18). The reason not to make the test itself depend on
    +    the MINGW prerequisite is to make a subsequent commit easier to read.
     
         1. https://lore.kernel.org/git/[email-masked]/
     
    @@ t/t7006-pager.sh: test_expect_success TTY 'git tag with auto-columns ' '
      	test_cmp expect actual
      '
      
    -+test_expect_success TTY,!MINGW 'git returns SIGPIPE on early pager exit' '
    ++test_expect_success TTY 'git returns SIGPIPE on early pager exit' '
     +	test_when_finished "rm pager-used" &&
     +	test_config core.pager ">pager-used; head -n 1; exit 0" &&
     +
    -+	OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    -+	test_match_signal 13 "$OUT" &&
    ++	if test_have_prereq !MINGW
    ++	then
    ++		OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    ++		test_match_signal 13 "$OUT"
    ++	else
    ++		test_terminal git log
    ++	fi &&
     +	test_path_is_file pager-used
     +'
     +
    -+test_expect_success TTY,!MINGW 'git returns SIGPIPE on early pager non-zero exit' '
    ++test_expect_success TTY 'git returns SIGPIPE on early pager non-zero exit' '
     +	test_when_finished "rm pager-used" &&
     +	test_config core.pager ">pager-used; head -n 1; exit 1" &&
     +
    -+	OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    -+	test_match_signal 13 "$OUT" &&
    ++	if test_have_prereq !MINGW
    ++	then
    ++		OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    ++		test_match_signal 13 "$OUT"
    ++	else
    ++		test_terminal git log
    ++	fi &&
     +	test_path_is_file pager-used
     +'
     +
    -+test_expect_success TTY,!MINGW 'git discards pager non-zero exit' '
    ++test_expect_success TTY 'git discards pager non-zero exit without SIGPIPE' '
     +	test_when_finished "rm pager-used" &&
     +	test_config core.pager "wc >pager-used; exit 1" &&
     +
    -+	OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    -+	test "$OUT" -eq 0 &&
    ++	if test_have_prereq !MINGW
    ++	then
    ++		OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    ++		test "$OUT" -eq 0
    ++	else
    ++		test_terminal git log
    ++	fi &&
    ++	test_path_is_file pager-used
    ++'
    ++
    ++test_expect_success TTY 'git discards nonexisting pager without SIGPIPE' '
    ++	test_when_finished "rm pager-used" &&
    ++	test_config core.pager "wc >pager-used; does-not-exist" &&
    ++
    ++	if test_have_prereq !MINGW
    ++	then
    ++		OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    ++		test "$OUT" -eq 0
    ++	else
    ++		test_terminal git log
    ++	fi &&
    ++	test_path_is_file pager-used
    ++'
    ++
    ++test_expect_success TTY 'git attempts to page to nonexisting pager command, gets SIGPIPE' '
    ++	test_config core.pager "does-not-exist" &&
    ++
    ++	if test_have_prereq !MINGW
    ++	then
    ++		OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    ++		test_match_signal 13 "$OUT"
    ++	else
    ++		test_terminal git log
    ++	fi
    ++'
    ++
    ++test_expect_success TTY 'git returns SIGPIPE on propagated signals from pager' '
    ++	test_when_finished "rm pager-used" &&
    ++	test_config core.pager ">pager-used; test-tool sigchain" &&
    ++
    ++	if test_have_prereq !MINGW
    ++	then
    ++		OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    ++		test_match_signal 13 "$OUT"
    ++	else
    ++		test_terminal git log
    ++	fi &&
     +	test_path_is_file pager-used
     +'
     +
-:  ----------- > 3:  0e4cbf80fe1 run-command: add braces for "if" block in wait_or_whine()
3:  d5db936bd11 ! 4:  527f69cf581 pager: properly log pager exit code when signalled
    @@ Commit message
         The wait_or_whine() is only called with a true "in_signal" from from
         finish_command_in_signal(), which in turn is only used in pager.c.
     
    -    I'm not quite sure about that BUG() case. Can we have a true in_signal
    -    and not have a true WIFEXITED(status)? I haven't been able to think of
    -    a test case for it.
    +    The "in_signal && !WIFEXITED(status)" case is not covered by
    +    tests. Let's log the default -1 in that case for good measure.
     
         1. The incorrect logging of the exit code in was seemingly copy/pasted
            into finish_command_in_signal() in ee4512ed481 (trace2: create new
    @@ Commit message
     
      ## run-command.c ##
     @@ run-command.c: static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
    - 
      	while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
      		;	/* nothing */
    --	if (in_signal)
    + 	if (in_signal) {
     -		return 0;
    -+	if (in_signal && WIFEXITED(status))
    -+		return WEXITSTATUS(status);
    -+	if (in_signal) {
    -+		BUG("was not expecting waitpid() status %d", status);
    -+		return -1;
    -+	}
    ++		if (WIFEXITED(status))
    ++			code = WEXITSTATUS(status);
    ++		return code;
    + 	}
      
      	if (waiting < 0) {
    - 		failed_errno = errno;
     
      ## t/t7006-pager.sh ##
     @@ t/t7006-pager.sh: test_expect_success TTY 'git tag with auto-columns ' '
      	test_cmp expect actual
      '
      
    --test_expect_success TTY,!MINGW 'git returns SIGPIPE on early pager exit' '
    -+test_expect_success TTY 'git returns SIGPIPE on early pager exit' '
    - 	test_when_finished "rm pager-used" &&
    ++test_expect_success 'setup trace2' '
    ++	GIT_TRACE2_BRIEF=1 &&
    ++	export GIT_TRACE2_BRIEF
    ++'
    ++
    + test_expect_success TTY 'git returns SIGPIPE on early pager exit' '
    +-	test_when_finished "rm pager-used" &&
    ++	test_when_finished "rm pager-used trace.normal" &&
      	test_config core.pager ">pager-used; head -n 1; exit 0" &&
     +	GIT_TRACE2="$(pwd)/trace.normal" &&
     +	export GIT_TRACE2 &&
     +	test_when_finished "unset GIT_TRACE2" &&
      
    --	OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    --	test_match_signal 13 "$OUT" &&
    -+	if test_have_prereq !MINGW
    -+	then
    -+		OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    -+		test_match_signal 13 "$OUT"
    -+	else
    -+		test_terminal git log
    -+	fi &&
    -+	grep "child_exit.* code:0 " trace.normal &&
    + 	if test_have_prereq !MINGW
    + 	then
    +@@ t/t7006-pager.sh: test_expect_success TTY 'git returns SIGPIPE on early pager exit' '
    + 	else
    + 		test_terminal git log
    + 	fi &&
    ++
    ++	grep child_exit trace.normal >child-exits &&
    ++	test_line_count = 1 child-exits &&
    ++	grep " code:0 " child-exits &&
      	test_path_is_file pager-used
      '
      
    --test_expect_success TTY,!MINGW 'git returns SIGPIPE on early pager non-zero exit' '
    -+test_expect_success TTY 'git returns SIGPIPE on early pager non-zero exit' '
    - 	test_when_finished "rm pager-used" &&
    + test_expect_success TTY 'git returns SIGPIPE on early pager non-zero exit' '
    +-	test_when_finished "rm pager-used" &&
    ++	test_when_finished "rm pager-used trace.normal" &&
      	test_config core.pager ">pager-used; head -n 1; exit 1" &&
     +	GIT_TRACE2="$(pwd)/trace.normal" &&
     +	export GIT_TRACE2 &&
     +	test_when_finished "unset GIT_TRACE2" &&
      
    --	OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    --	test_match_signal 13 "$OUT" &&
    -+	if test_have_prereq !MINGW
    -+	then
    -+		OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    -+		test_match_signal 13 "$OUT"
    -+	else
    -+		test_terminal git log
    -+	fi &&
    -+	grep "child_exit.* code:1 " trace.normal &&
    + 	if test_have_prereq !MINGW
    + 	then
    +@@ t/t7006-pager.sh: test_expect_success TTY 'git returns SIGPIPE on early pager non-zero exit' '
    + 	else
    + 		test_terminal git log
    + 	fi &&
    ++
    ++	grep child_exit trace.normal >child-exits &&
    ++	test_line_count = 1 child-exits &&
    ++	grep " code:1 " child-exits &&
      	test_path_is_file pager-used
      '
      
    --test_expect_success TTY,!MINGW 'git discards pager non-zero exit' '
    -+test_expect_success TTY 'git discards pager non-zero exit' '
    - 	test_when_finished "rm pager-used" &&
    + test_expect_success TTY 'git discards pager non-zero exit without SIGPIPE' '
    +-	test_when_finished "rm pager-used" &&
    ++	test_when_finished "rm pager-used trace.normal" &&
      	test_config core.pager "wc >pager-used; exit 1" &&
     +	GIT_TRACE2="$(pwd)/trace.normal" &&
     +	export GIT_TRACE2 &&
     +	test_when_finished "unset GIT_TRACE2" &&
      
    --	OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    --	test "$OUT" -eq 0 &&
    -+	if test_have_prereq !MINGW
    -+	then
    -+		OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    -+		test "$OUT" -eq 0
    -+	else
    -+		test_terminal git log
    -+	fi &&
    -+	grep "child_exit.* code:1 " trace.normal &&
    + 	if test_have_prereq !MINGW
    + 	then
    +@@ t/t7006-pager.sh: test_expect_success TTY 'git discards pager non-zero exit without SIGPIPE' '
    + 	else
    + 		test_terminal git log
    + 	fi &&
    ++
    ++	grep child_exit trace.normal >child-exits &&
    ++	test_line_count = 1 child-exits &&
    ++	grep " code:1 " child-exits &&
      	test_path_is_file pager-used
      '
      
    -+test_expect_success TTY 'git logs nonexisting pager invocation' '
    -+	test_config core.pager "does-not-exist" &&
    + test_expect_success TTY 'git discards nonexisting pager without SIGPIPE' '
    +-	test_when_finished "rm pager-used" &&
    ++	test_when_finished "rm pager-used trace.normal" &&
    + 	test_config core.pager "wc >pager-used; does-not-exist" &&
     +	GIT_TRACE2="$(pwd)/trace.normal" &&
     +	export GIT_TRACE2 &&
     +	test_when_finished "unset GIT_TRACE2" &&
    + 
    + 	if test_have_prereq !MINGW
    + 	then
    +@@ t/t7006-pager.sh: test_expect_success TTY 'git discards nonexisting pager without SIGPIPE' '
    + 	else
    + 		test_terminal git log
    + 	fi &&
     +
    -+	if test_have_prereq !MINGW
    -+	then
    -+		OUT=$( ((test_terminal git log; echo $? 1>&3) | :) 3>&1 ) &&
    -+		test_match_signal 13 "$OUT"
    -+	else
    -+		test_terminal git log
    ++	grep child_exit trace.normal >child-exits &&
    ++	test_line_count = 1 child-exits &&
    ++	grep " code:127 " child-exits &&
    + 	test_path_is_file pager-used
    + '
    + 
    + test_expect_success TTY 'git attempts to page to nonexisting pager command, gets SIGPIPE' '
    ++	test_when_finished "rm trace.normal" &&
    + 	test_config core.pager "does-not-exist" &&
    ++	GIT_TRACE2="$(pwd)/trace.normal" &&
    ++	export GIT_TRACE2 &&
    ++	test_when_finished "unset GIT_TRACE2" &&
    + 
    + 	if test_have_prereq !MINGW
    + 	then
    +@@ t/t7006-pager.sh: test_expect_success TTY 'git attempts to page to nonexisting pager command, gets
    + 		test_match_signal 13 "$OUT"
    + 	else
    + 		test_terminal git log
    +-	fi
     +	fi &&
    -+	grep "child_exit.* code:-1 " trace.normal
    -+'
     +
    - test_done
    ++	grep child_exit trace.normal >child-exits &&
    ++	test_line_count = 1 child-exits &&
    ++	grep " code:-1 " child-exits
    + '
    + 
    + test_expect_success TTY 'git returns SIGPIPE on propagated signals from pager' '
    +-	test_when_finished "rm pager-used" &&
    ++	test_when_finished "rm pager-used trace.normal" &&
    + 	test_config core.pager ">pager-used; test-tool sigchain" &&
    ++	GIT_TRACE2="$(pwd)/trace.normal" &&
    ++	export GIT_TRACE2 &&
    ++	test_when_finished "unset GIT_TRACE2" &&
    + 
    + 	if test_have_prereq !MINGW
    + 	then
    +@@ t/t7006-pager.sh: test_expect_success TTY 'git returns SIGPIPE on propagated signals from pager' '
    + 	else
    + 		test_terminal git log
    + 	fi &&
    ++
    ++	grep child_exit trace.normal >child-exits &&
    ++	test_line_count = 1 child-exits &&
    ++	grep " code:143 " child-exits &&
    + 	test_path_is_file pager-used
    + '
    + 
-:  ----------- > 5:  842f42340d0 WIP pager: respect exit code of pager over SIGPIPE
-- 
2.30.0.284.gd98b1dd5eaa7