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[PATCH v2 0/2] tests: replace mingw_test_cmp with a helper in C

From
Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Date
Sep 6, 2022, 13:10 UTC
Message-ID
<pull.1309.v2.git.1662469859.gitgitgadget@gmail.com>
In-Reply-To
<pull.1309.git.1659106382128.gitgitgadget@gmail.com>

On the heels of sending a patch to fix a performance regression due to a mis-use of test_cmp [https://lore.kernel.org/git/b9203ea247776332e4b6f519aa27d541207adc2f.1659097724.git.gitgitgadget@gmail.com/], I was curious to see whether Git for Windows had the same issue. And it does not [https://github.com/git-for-windows/git/runs/7556381815?check_suite_focus=true#step:5:127]: it passes t5351 in 22 seconds, even while using test_cmp to compare pack files [https://github.com/git-for-windows/git/blob/3922f62f0d5991e9fe0a0817ebf89a91339c7705/t/t5351-unpack-large-objects.sh#L90].

The answer is of course that a test helper written in C is much faster than writing the same in Bash, especially on Windows. This is especially sad when said Bash code is only used on Windows. So I pulled out this helper from the years-long effort to let Git for Windows use BusyBox' ash to run the test suite. The result is this patch, which has been in Git for Windows since June 2018.

Changes since v1:
 * Fixed double "with" in the commit message.
Johannes Schindelin (2):
  t0021: use Windows-friendly `pwd`
  tests: replace mingw_test_cmp with a helper in C
 Makefile                 |  1 +
 t/helper/test-text-cmp.c | 78 ++++++++++++++++++++++++++++++++++++++++
 t/helper/test-tool.c     |  1 +
 t/helper/test-tool.h     |  1 +
 t/t0021-conversion.sh    |  4 +--
 t/test-lib-functions.sh  | 68 +----------------------------------
 t/test-lib.sh            |  2 +-
 7 files changed, 85 insertions(+), 70 deletions(-)
 create mode 100644 t/helper/test-text-cmp.c
base-commit: 23b219f8e3f2adfb0441e135f0a880e6124f766c
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1309%2Fdscho%2Fmingw-test-cmp-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1309/dscho/mingw-test-cmp-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1309
Range-diff vs v1:
 -:  ----------- > 1:  ad7c41401ee t0021: use Windows-friendly `pwd`
 1:  eacbbc53700 ! 2:  1f5366f1379 tests: replace mingw_test_cmp with a helper in C
     @@ Commit message
          tests: replace mingw_test_cmp with a helper in C
      
          This helper is more performant than running the `mingw_test_cmp` code
     -    with with MSYS2's Bash. And a lot more readable.
     +    with MSYS2's Bash. And a lot more readable.
      
          To accommodate t1050, which wants to compare files weighing in with 3MB
          (falling outside of t1050's malloc limit of 1.5MB), we simply lift the
     @@ Commit message
          Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
      
       ## Makefile ##
     -@@ Makefile: TEST_BUILTINS_OBJS += test-advise.o
     - TEST_BUILTINS_OBJS += test-bitmap.o
     - TEST_BUILTINS_OBJS += test-bloom.o
     - TEST_BUILTINS_OBJS += test-chmtime.o
     -+TEST_BUILTINS_OBJS += test-cmp.o
     - TEST_BUILTINS_OBJS += test-config.o
     - TEST_BUILTINS_OBJS += test-crontab.o
     - TEST_BUILTINS_OBJS += test-csprng.o
     +@@ Makefile: TEST_BUILTINS_OBJS += test-string-list.o
     + TEST_BUILTINS_OBJS += test-submodule-config.o
     + TEST_BUILTINS_OBJS += test-submodule-nested-repo-config.o
     + TEST_BUILTINS_OBJS += test-subprocess.o
     ++TEST_BUILTINS_OBJS += test-text-cmp.o
     + TEST_BUILTINS_OBJS += test-trace2.o
     + TEST_BUILTINS_OBJS += test-urlmatch-normalization.o
     + TEST_BUILTINS_OBJS += test-userdiff.o
      
     - ## t/helper/test-cmp.c (new) ##
     + ## t/helper/test-text-cmp.c (new) ##
      @@
      +#include "test-tool.h"
      +#include "git-compat-util.h"
     @@ t/helper/test-cmp.c (new)
      +static int run_diff(const char *path1, const char *path2)
      +{
      +	const char *argv[] = {
     -+		"diff", "--no-index", NULL, NULL, NULL
     ++		"diff", "--no-index", "--", NULL, NULL, NULL
      +	};
      +	const char *env[] = {
      +		"GIT_PAGER=cat",
     @@ t/helper/test-cmp.c (new)
      +		NULL
      +	};
      +
     -+	argv[2] = path1;
     -+	argv[3] = path2;
     ++	argv[3] = path1;
     ++	argv[4] = path2;
      +	return run_command_v_opt_cd_env(argv,
      +					RUN_COMMAND_NO_STDIN | RUN_GIT_CMD,
      +					NULL, env);
      +}
      +
     -+int cmd__cmp(int argc, const char **argv)
     ++int cmd__text_cmp(int argc, const char **argv)
      +{
      +	FILE *f0, *f1;
      +	struct strbuf b0 = STRBUF_INIT, b1 = STRBUF_INIT;
     @@ t/helper/test-cmp.c (new)
      +	if (argc != 3)
      +		die("Require exactly 2 arguments, got %d", argc);
      +
     ++	if (!strcmp(argv[1], "-") && !strcmp(argv[2], "-"))
     ++		die("only one parameter can refer to `stdin` but not both");
     ++
      +	if (!(f0 = !strcmp(argv[1], "-") ? stdin : fopen(argv[1], "r")))
      +		return error_errno("could not open '%s'", argv[1]);
      +	if (!(f1 = !strcmp(argv[2], "-") ? stdin : fopen(argv[2], "r"))) {
     @@ t/helper/test-cmp.c (new)
      +			if (r1 == EOF)
      +				return 0;
      +cmp_failed:
     -+			if (!run_diff(argv[1], argv[2]))
     ++			if (!strcmp(argv[1], "-") || !strcmp(argv[2], "-"))
     ++				warning("cannot show diff because `stdin` was already consumed");
     ++			else if (!run_diff(argv[1], argv[2]))
      +				die("Huh? 'diff --no-index %s %s' succeeded",
      +				    argv[1], argv[2]);
      +			return 1;
     @@ t/helper/test-cmp.c (new)
      
       ## t/helper/test-tool.c ##
      @@ t/helper/test-tool.c: static struct test_cmd cmds[] = {
     - 	{ "bitmap", cmd__bitmap },
     - 	{ "bloom", cmd__bloom },
     - 	{ "chmtime", cmd__chmtime },
     -+	{ "cmp", cmd__cmp },
     - 	{ "config", cmd__config },
     - 	{ "crontab", cmd__crontab },
     - 	{ "csprng", cmd__csprng },
     + 	{ "submodule-config", cmd__submodule_config },
     + 	{ "submodule-nested-repo-config", cmd__submodule_nested_repo_config },
     + 	{ "subprocess", cmd__subprocess },
     ++	{ "text-cmp", cmd__text_cmp },
     + 	{ "trace2", cmd__trace2 },
     + 	{ "userdiff", cmd__userdiff },
     + 	{ "urlmatch-normalization", cmd__urlmatch_normalization },
      
       ## t/helper/test-tool.h ##
     -@@ t/helper/test-tool.h: int cmd__advise_if_enabled(int argc, const char **argv);
     - int cmd__bitmap(int argc, const char **argv);
     - int cmd__bloom(int argc, const char **argv);
     - int cmd__chmtime(int argc, const char **argv);
     -+int cmd__cmp(int argc, const char **argv);
     - int cmd__config(int argc, const char **argv);
     - int cmd__crontab(int argc, const char **argv);
     - int cmd__csprng(int argc, const char **argv);
     +@@ t/helper/test-tool.h: int cmd__string_list(int argc, const char **argv);
     + int cmd__submodule_config(int argc, const char **argv);
     + int cmd__submodule_nested_repo_config(int argc, const char **argv);
     + int cmd__subprocess(int argc, const char **argv);
     ++int cmd__text_cmp(int argc, const char **argv);
     + int cmd__trace2(int argc, const char **argv);
     + int cmd__userdiff(int argc, const char **argv);
     + int cmd__urlmatch_normalization(int argc, const char **argv);
      
       ## t/test-lib-functions.sh ##
      @@ t/test-lib-functions.sh: test_expect_code () {
     @@ t/test-lib.sh: case $uname_s in
       	test_set_prereq GREP_STRIPS_CR
       	test_set_prereq WINDOWS
      -	GIT_TEST_CMP=mingw_test_cmp
     -+	GIT_TEST_CMP="test-tool cmp"
     ++	GIT_TEST_CMP="test-tool text-cmp"
       	;;
       *CYGWIN*)
       	test_set_prereq POSIXPERM
-- 
gitgitgadget
Previous: Junio C HamanoNext: Johannes Schindelin via GitGitGadget
Message 14 of 58 in “tests: replace mingw_test_cmp with a helper in C”
  1. tests: replace mingw_test_cmp with a helper in CJohannes Schindelin via GitGitGadget, Jul 29, 2022
  2. Johannes SchindelinJul 29, 2022
  3. Junio C HamanoJul 29, 2022
  4. Johannes SchindelinSep 6, 2022
  5. René ScharfeSep 7, 2022
  6. Junio C HamanoSep 7, 2022
  7. Re* [PATCH] tests: replace mingw_test_cmp with a helper in CJunio C Hamano, Sep 7, 2022
  8. René ScharfeSep 7, 2022
  9. Junio C HamanoSep 8, 2022
  10. René ScharfeSep 8, 2022
  11. Ævar Arnfjörð BjarmasonSep 8, 2022
  12. Johannes SchindelinSep 8, 2022
  13. Junio C HamanoSep 8, 2022
  14. 0/2 tests: replace mingw_test_cmp with a helper in CJohannes Schindelin via GitGitGadget, Sep 6, 2022
  15. 1/2 t0021: use Windows-friendly `pwd`Johannes Schindelin via GitGitGadget, Sep 6, 2022
  16. 2/2 tests: replace mingw_test_cmp with a helper in CJohannes Schindelin via GitGitGadget, Sep 6, 2022
  17. Ævar Arnfjörð BjarmasonSep 7, 2022
  18. Ævar Arnfjörð BjarmasonSep 7, 2022
  19. Junio C HamanoSep 7, 2022
  20. Johannes SchindelinSep 7, 2022
  21. 0/2 tests: replace mingw_test_cmp with a helper in CJohannes Schindelin via GitGitGadget, Nov 12, 2022
  22. 1/2 t0021: use Windows-friendly `pwd`Johannes Schindelin via GitGitGadget, Nov 12, 2022
  23. 2/2 tests(mingw): avoid very slow `mingw_test_cmp`Johannes Schindelin via GitGitGadget, Nov 12, 2022
  24. Taylor BlauNov 13, 2022
  25. Johannes SchindelinNov 14, 2022
  26. Junio C HamanoNov 18, 2022
  27. Taylor BlauNov 19, 2022
  28. Ævar Arnfjörð BjarmasonNov 19, 2022
  29. Johannes SixtNov 19, 2022
  30. René ScharfeNov 19, 2022
  31. Torsten BögershausenNov 20, 2022
  32. Johannes SixtNov 21, 2022
  33. Junio C HamanoNov 21, 2022
  34. Phillip WoodNov 14, 2022
  35. Johannes SchindelinNov 14, 2022
  36. Ævar Arnfjörð BjarmasonNov 14, 2022
  37. Johannes SchindelinNov 14, 2022
  38. Ævar Arnfjörð BjarmasonNov 14, 2022
  39. Junio C HamanoNov 18, 2022
  40. Taylor BlauNov 19, 2022
  41. Ævar Arnfjörð BjarmasonNov 19, 2022
  42. Junio C HamanoNov 21, 2022
  43. 0/2 tests(mingw): avoid super-slow mingw_test_cmpJohannes Schindelin via GitGitGadget, Nov 14, 2022
  44. 1/2 t0021: use Windows-friendly `pwd`Johannes Schindelin via GitGitGadget, Nov 14, 2022
  45. 2/2 tests(mingw): avoid very slow `mingw_test_cmp`Johannes Schindelin via GitGitGadget, Nov 14, 2022
  46. Taylor BlauNov 14, 2022
  47. Johannes SchindelinNov 18, 2022
  48. Taylor BlauNov 18, 2022
  49. Johannes SchindelinNov 20, 2022
  50. Taylor BlauNov 21, 2022
  51. 0/2 tests(mingw): avoid super-slow mingw_test_cmpJohannes Schindelin via GitGitGadget, Dec 6, 2022
  52. 2/2 tests(mingw): avoid very slow `mingw_test_cmp`Johannes Schindelin via GitGitGadget, Dec 6, 2022
  53. Ævar Arnfjörð BjarmasonDec 6, 2022
  54. Johannes SixtDec 6, 2022
  55. René ScharfeDec 6, 2022
  56. Junio C HamanoDec 7, 2022
  57. Taylor BlauDec 7, 2022
  58. 1/2 t0021: use Windows-friendly `pwd`Johannes Schindelin via GitGitGadget, Dec 6, 2022

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