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[PATCH v3 2/2] test-lib.sh: remove the now-unused "test_untraceable" facility

From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date
Dec 10, 2021, 10:07 UTC
Message-ID
<patch-v3-2.2-a7fc794e20d-20211210T100512Z-avarab@gmail.com>
In-Reply-To
<cover-v3-0.2-00000000000-20211210T100512Z-avarab@gmail.com>

In the preceding commit the use of "test_untraceable=UnfortunatelyYes" was removed from "t1510-repo-setup.sh" in favor of more narrow redirections of the output of specific commands (and not entire sub-shells or functions).

This is in line with the fixes in the series that introduced the "test_untraceable" facility. See 571e472dc43 (Merge branch 'sg/test-x', 2018-03-14) for the series as a whole, and e.g. 91538d0cde9 (t5570-git-daemon: don't check the stderr of a subshell, 2018-02-24) for a commit that's in line with the changes in the preceding commit.

We've thus solved the TODO item noted when "test_untraceable" was added to "t1510-repo-setup.sh" in 58275069288 (t1510-repo-setup: mark as untraceable with '-x', 2018-02-24).

So let's remove the feature entirely. Not only is it currently unused, but it actively encourages an anti-pattern in our tests. We should be testing the output of specific commands, not entire subshells or functions.

That the "-x" output had to be disabled as a result is only one symptom, but even under bash those tests will be harder to debug as the subsequent check of the redirected file will be far removed from the command that emitted the output.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 t/README      |  3 ---
 t/test-lib.sh | 66 ++++++---------------------------------------------
 2 files changed, 7 insertions(+), 62 deletions(-)
diff --git a/t/README b/t/README
index 29f72354bf1..3d30bbff34a 100644
--- a/t/README
+++ b/t/README
@@ -86,9 +86,6 @@ appropriately before running "make". Short options can be bundled, i.e.
 -x::
 	Turn on shell tracing (i.e., `set -x`) during the tests
 	themselves. Implies `--verbose`.
-	Ignored in test scripts that set the variable 'test_untraceable'
-	to a non-empty value, unless it's run with a Bash version
-	supporting BASH_XTRACEFD, i.e. v4.1 or later.
 
 -d::
 --debug::
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 57efcc5e97a..b008716917b 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -381,29 +381,6 @@ then
 	exit
 fi
 
-if test -n "$trace" && test -n "$test_untraceable"
-then
-	# '-x' tracing requested, but this test script can't be reliably
-	# traced, unless it is run with a Bash version supporting
-	# BASH_XTRACEFD (introduced in Bash v4.1).
-	#
-	# Perform this version check _after_ the test script was
-	# potentially re-executed with $TEST_SHELL_PATH for '--tee' or
-	# '--verbose-log', so the right shell is checked and the
-	# warning is issued only once.
-	if test -n "$BASH_VERSION" && eval '
-	     test ${BASH_VERSINFO[0]} -gt 4 || {
-	       test ${BASH_VERSINFO[0]} -eq 4 &&
-	       test ${BASH_VERSINFO[1]} -ge 1
-	     }
-	   '
-	then
-		: Executed by a Bash version supporting BASH_XTRACEFD.  Good.
-	else
-		echo >&2 "warning: ignoring -x; '$0' is untraceable without BASH_XTRACEFD"
-		trace=
-	fi
-fi
 if test -n "$trace" && test -z "$verbose_log"
 then
 	verbose=t
@@ -650,19 +627,6 @@ else
 	exec 4>/dev/null 3>/dev/null
 fi
 
-# Send any "-x" output directly to stderr to avoid polluting tests
-# which capture stderr. We can do this unconditionally since it
-# has no effect if tracing isn't turned on.
-#
-# Note that this sets up the trace fd as soon as we assign the variable, so it
-# must come after the creation of descriptor 4 above. Likewise, we must never
-# unset this, as it has the side effect of closing descriptor 4, which we
-# use to show verbose tests to the user.
-#
-# Note also that we don't need or want to export it. The tracing is local to
-# this shell, and we would not want to influence any shells we exec.
-BASH_XTRACEFD=4
-
 test_failure=0
 test_count=0
 test_fixed=0
@@ -949,36 +913,20 @@ test_eval_ () {
 	# the shell from printing the "set +x" to turn it off (nor the saving
 	# of $? before that). But we can make sure that the output goes to
 	# /dev/null.
-	#
-	# There are a few subtleties here:
-	#
-	#   - we have to redirect descriptor 4 in addition to 2, to cover
-	#     BASH_XTRACEFD
-	#
-	#   - the actual eval has to come before the redirection block (since
-	#     it needs to see descriptor 4 to set up its stderr)
-	#
-	#   - likewise, any error message we print must be outside the block to
-	#     access descriptor 4
-	#
-	#   - checking $? has to come immediately after the eval, but it must
-	#     be _inside_ the block to avoid polluting the "set -x" output
-	#
-
-	test_eval_inner_ "$@" </dev/null >&3 2>&4
 	{
+		test_eval_inner_ "$@" </dev/null >&3 2>&4
 		test_eval_ret_=$?
 		if want_trace
 		then
 			test 1 = $trace_level_ && set +x
 			trace_level_=$(($trace_level_-1))
-		fi
-	} 2>/dev/null 4>&2
 
-	if test "$test_eval_ret_" != 0 && want_trace
-	then
-		say_color error >&4 "error: last command exited with \$?=$test_eval_ret_"
-	fi
+			if test "$test_eval_ret_" != 0
+			then
+				say_color error >&4 "error: last command exited with \$?=$test_eval_ret_"
+			fi
+		fi
+	} 2>/dev/null
 	return $test_eval_ret_
 }
 
-- 
2.34.1.932.g36842105b61
Previous: Ævar Arnfjörð BjarmasonNext: SZEDER Gábor
Message 31 of 50 in “Set GIT_TRACE2_EVENT_NESTING in test-lib.sh”
  1. 0/2 Set GIT_TRACE2_EVENT_NESTING in test-lib.shDerrick Stolee via GitGitGadget, Nov 29, 2021
  2. 1/2 test-lib.sh: set GIT_TRACE2_EVENT_NESTINGDerrick Stolee via GitGitGadget, Nov 29, 2021
  3. Ævar Arnfjörð BjarmasonNov 29, 2021
  4. Junio C HamanoNov 29, 2021
  5. Junio C HamanoNov 29, 2021
  6. 2/2 t/t*: remove custom GIT_TRACE2_EVENT_NESTINGDerrick Stolee via GitGitGadget, Nov 29, 2021
  7. Jeff KingNov 29, 2021
  8. Jeff KingNov 29, 2021
  9. Taylor BlauNov 30, 2021
  10. Derrick StoleeNov 30, 2021
  11. Jeff HostetlerNov 30, 2021
  12. Jeff KingDec 1, 2021
  13. test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFDÆvar Arnfjörð Bjarmason, Nov 29, 2021
  14. Eric SunshineNov 29, 2021
  15. Jeff KingNov 30, 2021
  16. Ævar Arnfjörð BjarmasonNov 30, 2021
  17. SZEDER GáborNov 30, 2021
  18. Ævar Arnfjörð BjarmasonDec 1, 2021
  19. Jeff KingDec 1, 2021
  20. Junio C HamanoDec 1, 2021
  21. 0/2 test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFDÆvar Arnfjörð Bjarmason, Dec 1, 2021
  22. 1/2 t1510: remove need for "test_untraceable", retain coverageÆvar Arnfjörð Bjarmason, Dec 1, 2021
  23. SZEDER GáborDec 2, 2021
  24. SZEDER GáborDec 2, 2021
  25. Jeff KingDec 10, 2021
  26. Ævar Arnfjörð BjarmasonDec 10, 2021
  27. SZEDER GáborFeb 6, 2022
  28. 2/2 test-lib.sh: remove the now-unused "test_untraceable" facilityÆvar Arnfjörð Bjarmason, Dec 1, 2021
  29. 0/2 test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFDÆvar Arnfjörð Bjarmason, Dec 10, 2021
  30. 1/2 t1510: remove need for "test_untraceable", retain coverageÆvar Arnfjörð Bjarmason, Dec 10, 2021
  31. 2/2 test-lib.sh: remove the now-unused "test_untraceable" facilityÆvar Arnfjörð Bjarmason, Dec 10, 2021
  32. SZEDER GáborDec 12, 2021
  33. Ævar Arnfjörð BjarmasonDec 12, 2021
  34. SZEDER GáborDec 12, 2021
  35. Junio C HamanoDec 13, 2021
  36. Jeff KingDec 14, 2021
  37. Junio C HamanoDec 15, 2021
  38. Jeff KingDec 15, 2021
  39. Junio C HamanoDec 15, 2021
  40. Ævar Arnfjörð BjarmasonDec 16, 2021
  41. 0/3 test-lib.sh: have all tests pass under "-x", remove BASH_XTRACEFDÆvar Arnfjörð Bjarmason, Dec 13, 2021
  42. 1/3 t1510: remove need for "test_untraceable", retain coverageÆvar Arnfjörð Bjarmason, Dec 13, 2021
  43. 2/3 test-lib.sh: remove the now-unused "test_untraceable" facilityÆvar Arnfjörð Bjarmason, Dec 13, 2021
  44. 3/3 test-lib.sh: remove "BASH_XTRACEFD"Ævar Arnfjörð Bjarmason, Dec 13, 2021
  45. SZEDER GáborFeb 21, 2022
  46. Ævar Arnfjörð BjarmasonFeb 22, 2022
  47. SZEDER GáborDec 13, 2021
  48. Ævar Arnfjörð BjarmasonFeb 21, 2022
  49. SZEDER GáborFeb 21, 2022
  50. Ævar Arnfjörð BjarmasonFeb 21, 2022

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