On Mon, Mar 18, 2019 at 12:47 AM Ævar Arnfjörð Bjarmason
[off-list ref] wrote:

On Sun, Mar 17 2019, Jonathan Chang wrote:

quoted

The exit code of the upstream in a pipe is ignored thus we should avoid
using it. By writing out the output of the git command to a file, we can
test the exit codes of both the commands.

Signed-off-by: Jonathan Chang <redacted>
---
 t/t0000-basic.sh | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index 53821f5817..47666b013e 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh

@@ -1118,27 +1118,25 @@ P=$(test_oid root)

 test_expect_success 'git commit-tree records the correct tree in a commit' '
      commit0=$(echo NO | git commit-tree $P) &&
-     tree=$(git show --pretty=raw $commit0 |
-              sed -n -e "s/^tree //p" -e "/^author /q") &&
+     git show --pretty=raw $commit0 >actual &&
+     tree=$(sed -n -e "s/^tree //p" -e "/^author /q" actual) &&
      test "z$tree" = "z$P"

This change is an improvement just changing the "git" invocations. But I
wonder as we're reviewing this / churning this if we couldn't also
modernize this style to just:

    git .. >tmp &&
    sed -n -e <tmp >actual &&
    test_must_be_empty actual

Do you mean something like this:

-       git show --pretty=raw $commit0 >actual &&
-       tree=$(sed -n -e "s/^tree //p" -e "/^author /q" actual) &&
-       test "z$tree" = "z$P"
+       git show --pretty=raw $commit0 >tmp &&
+       sed -n -e "/$P/d" -e "s/^tree //p" -e "/^author /q" tmp >actual &&
+       test_must_be_empty actual

It works. But the semantic is different if we use test_must_be_empty.
I wonder if you mean test_cmp because I found some commits[1 2 3]
that changes 'test "z...' to use test_cmp with 'git log -G 'test "z' --oneline'
and git-show. However, they are all around 2013, so I'm not so sure
this is what you mean either.

I did found some use of sed's 'd' function in conjunction with
test_must_be_empty, using:
  git grep -A 5 'sed .*/d' | grep -B 5 'test_must_be_empty'
However, they don't use parameter expansion in sed.

There are some places where parameter expansion is used in sed, but
that would require test_cmp in this case, and would need to write to
another file to compare.

Maybe this 'test "z$A" = "z$B"' syntax is fine, yet most of the existing
usages are added around 12 years ago according git-blame I saw on
github.


[1]: 03c893cbf9 ("t1006: modernize output comparisons", 2013-07-10)
[2]: 848575d833 ("push test: simplify check of push result", 2013-03-18)
[3]: ed838e6615 ("t1300: style updates", 2012-10-23)

quoted

@@ -1162,12 +1161,13 @@ test_expect_success 'very long name in the index handled sanely' '
      >path4 &&
      git update-index --add path4 &&
      (
-             git ls-files -s path4 |
-             sed -e "s/      .*/     /" |
+             git ls-files -s path4 >actual &&
+             sed -e "s/      .*/     /" actual |
              tr -d "\012" &&
              echo "$a"
      ) | git update-index --index-info &&
-     len=$(git ls-files "a*" | wc -c) &&
+     git ls-files "a*" >actual &&
+     len=$(wc -c <actual) &&
      test $len = 4098

Ditto. Maybe the initial author wanted to avoid writing out 4k lines,
but now that we're doing so anyway...

This is 'wc -c', so I think I don't have to modify it?

By the way, I found 2 lines that can be changed to use test_must_be_empty
in t0000-basic.sh. I paste the diff below:
---

@@ -51,7 +51,7 @@ test_expect_success 'verify that the running shell

supports "local"' '

 test_expect_success '.git/objects should be empty after git init in
an empty repo' '
        find .git/objects -type f -print >should-be-empty &&
-       test_line_count = 0 should-be-empty
+       test_must_be_empty should-be-empty
 '

 # also it should have 2 subdirectories; no fan-out anymore, pack, and info.

@@ -1110,7 +1110,7 @@ test_expect_success 'git update-index --refresh

should succeed' '

 test_expect_success 'no diff after checkout and git update-index --refresh' '
        git diff-files >current &&
-       cmp -s current /dev/null
+       test_must_be_empty current
 '