t3404: avoid losing exit status with focus on git show and git cat-file

The exit code of the preceding command in a pipe is disregarded. So
if that preceding command is a Git command that fails, the test would
not fail. Instead, by saving the output of that Git command to a file,
and removing the pipe, we make sure the test will fail if that Git
command fails. This particular patch focuses on all `git show` and
some instances of `git cat-file`.

Signed-off-by: Usman Akinyemi <[email protected]>
Signed-off-by: Taylor Blau <[email protected]>

Author: Unique-Usman

t/t3404-rebase-interactive.sh

@@ -319,7 +319,8 @@ test_expect_success 'retain authorship' '
 	GIT_AUTHOR_NAME="Twerp Snog" git commit -m "different author" &&
 	git tag twerp &&
 	git rebase -i --onto primary HEAD^ &&
-	git show HEAD | grep "^Author: Twerp Snog"
+	git show HEAD >actual &&
+	grep "^Author: Twerp Snog" actual
 '
 
 test_expect_success 'retain authorship w/ conflicts' '
@@ -360,7 +361,8 @@ test_expect_success 'squash' '
 '
 
 test_expect_success 'retain authorship when squashing' '
-	git show HEAD | grep "^Author: Twerp Snog"
+	git show HEAD >actual &&
+	grep "^Author: Twerp Snog" actual
 '
 
 test_expect_success '--continue tries to commit' '
@@ -374,7 +376,8 @@ test_expect_success '--continue tries to commit' '
 		FAKE_COMMIT_MESSAGE="chouette!" git rebase --continue
 	) &&
 	test_cmp_rev HEAD^ new-branch1 &&
-	git show HEAD | grep chouette
+	git show HEAD >actual &&
+	grep chouette actual
 '
 
 test_expect_success 'verbose flag is heeded, even after --continue' '
@@ -397,7 +400,9 @@ test_expect_success 'multi-squash only fires up editor once' '
 			git rebase -i $base
 	) &&
 	test $base = $(git rev-parse HEAD^) &&
-	test 1 = $(git show | grep ONCE | wc -l)
+	git show >output &&
+	count=$(grep ONCE output | wc -l) &&
+	test 1 = $count
 '
 
 test_expect_success 'multi-fixup does not fire up editor' '
@@ -410,7 +415,9 @@ test_expect_success 'multi-fixup does not fire up editor' '
 			git rebase -i $base
 	) &&
 	test $base = $(git rev-parse HEAD^) &&
-	test 0 = $(git show | grep NEVER | wc -l) &&
+	git show >output &&
+	count=$(grep NEVER output | wc -l) &&
+	test 0 = $count &&
 	git checkout @{-1} &&
 	git branch -D multi-fixup
 '
@@ -428,7 +435,9 @@ test_expect_success 'commit message used after conflict' '
 			git rebase --continue
 	) &&
 	test $base = $(git rev-parse HEAD^) &&
-	test 1 = $(git show | grep ONCE | wc -l) &&
+	git show >output &&
+	count=$(grep ONCE output | wc -l) &&
+	test 1 = $count &&
 	git checkout @{-1} &&
 	git branch -D conflict-fixup
 '
@@ -446,7 +455,9 @@ test_expect_success 'commit message retained after conflict' '
 			git rebase --continue
 	) &&
 	test $base = $(git rev-parse HEAD^) &&
-	test 2 = $(git show | grep TWICE | wc -l) &&
+	git show >output &&
+	count=$(grep TWICE output | wc -l) &&
+	test 2 = $count &&
 	git checkout @{-1} &&
 	git branch -D conflict-squash
 '
@@ -470,10 +481,10 @@ test_expect_success 'squash and fixup generate correct log messages' '
 	) &&
 	git cat-file commit HEAD | sed -e 1,/^\$/d > actual-squash-fixup &&
 	test_cmp expect-squash-fixup actual-squash-fixup &&
-	git cat-file commit HEAD@{2} |
-		grep "^# This is a combination of 3 commits\."  &&
-	git cat-file commit HEAD@{3} |
-		grep "^# This is a combination of 2 commits\."  &&
+	git cat-file commit HEAD@{2} >actual &&
+	grep "^# This is a combination of 3 commits\." actual &&
+	git cat-file commit HEAD@{3} >actual &&
+	grep "^# This is a combination of 2 commits\." actual  &&
 	git checkout @{-1} &&
 	git branch -D squash-fixup
 '
@@ -489,7 +500,9 @@ test_expect_success 'squash ignores comments' '
 			git rebase -i $base
 	) &&
 	test $base = $(git rev-parse HEAD^) &&
-	test 1 = $(git show | grep ONCE | wc -l) &&
+	git show >output &&
+	count=$(grep ONCE output | wc -l) &&
+	test 1 = $count &&
 	git checkout @{-1} &&
 	git branch -D skip-comments
 '
@@ -505,7 +518,9 @@ test_expect_success 'squash ignores blank lines' '
 			git rebase -i $base
 	) &&
 	test $base = $(git rev-parse HEAD^) &&
-	test 1 = $(git show | grep ONCE | wc -l) &&
+	git show >output &&
+	count=$(grep ONCE output | wc -l) &&
+	test 1 = $count &&
 	git checkout @{-1} &&
 	git branch -D skip-blank-lines
 '
@@ -572,7 +587,8 @@ test_expect_success '--continue tries to commit, even for "edit"' '
 		FAKE_COMMIT_MESSAGE="chouette!" git rebase --continue
 	) &&
 	test edited = $(git show HEAD:file7) &&
-	git show HEAD | grep chouette &&
+	git show HEAD >actual &&
+	grep chouette actual &&
 	test $parent = $(git rev-parse HEAD^)
 '
 
@@ -757,19 +773,23 @@ test_expect_success 'reword' '
 		set_fake_editor &&
 		FAKE_LINES="1 2 3 reword 4" FAKE_COMMIT_MESSAGE="E changed" \
 			git rebase -i A &&
-		git show HEAD | grep "E changed" &&
+		git show HEAD >actual &&
+		grep "E changed" actual &&
 		test $(git rev-parse primary) != $(git rev-parse HEAD) &&
 		test_cmp_rev primary^ HEAD^ &&
 		FAKE_LINES="1 2 reword 3 4" FAKE_COMMIT_MESSAGE="D changed" \
 			git rebase -i A &&
-		git show HEAD^ | grep "D changed" &&
+		git show HEAD^ >actual &&
+		grep "D changed" actual &&
 		FAKE_LINES="reword 1 2 3 4" FAKE_COMMIT_MESSAGE="B changed" \
 			git rebase -i A &&
-		git show HEAD~3 | grep "B changed" &&
+		git show HEAD~3 >actual &&
+		grep "B changed" actual &&
 		FAKE_LINES="1 r 2 pick 3 p 4" FAKE_COMMIT_MESSAGE="C changed" \
 			git rebase -i A
 	) &&
-	git show HEAD~2 | grep "C changed"
+	git show HEAD~2 >actual &&
+	grep "C changed" actual
 '
 
 test_expect_success 'no uncommitted changes when rewording and the todo list is reloaded' '
@@ -1003,8 +1023,10 @@ test_expect_success 'rebase -i --root retain root commit author and message' '
 		set_fake_editor &&
 		FAKE_LINES="2" git rebase -i --root
 	) &&
-	git cat-file commit HEAD | grep -q "^author Twerp Snog" &&
-	git cat-file commit HEAD | grep -q "^different author$"
+	git cat-file commit HEAD >output &&
+	grep -q "^author Twerp Snog" output &&
+	git cat-file commit HEAD >actual &&
+	grep -q "^different author$" actual
 '
 
 test_expect_success 'rebase -i --root temporary sentinel commit' '
@@ -1013,7 +1035,8 @@ test_expect_success 'rebase -i --root temporary sentinel commit' '
 		set_fake_editor &&
 		test_must_fail env FAKE_LINES="2" git rebase -i --root
 	) &&
-	git cat-file commit HEAD | grep "^tree $EMPTY_TREE" &&
+	git cat-file commit HEAD >actual &&
+	grep "^tree $EMPTY_TREE" actual &&
 	git rebase --abort
 '
 
@@ -1036,7 +1059,8 @@ test_expect_success 'rebase -i --root reword original root commit' '
 		FAKE_LINES="reword 1 2" FAKE_COMMIT_MESSAGE="A changed" \
 			git rebase -i --root
 	) &&
-	git show HEAD^ | grep "A changed" &&
+	git show HEAD^ >actual &&
+	grep "A changed" actual &&
 	test -z "$(git show -s --format=%p HEAD^)"
 '
 
@@ -1048,7 +1072,8 @@ test_expect_success 'rebase -i --root reword new root commit' '
 		FAKE_LINES="reword 3 1" FAKE_COMMIT_MESSAGE="C changed" \
 		git rebase -i --root
 	) &&
-	git show HEAD^ | grep "C changed" &&
+	git show HEAD^ >actual &&
+	grep "C changed" actual &&
 	test -z "$(git show -s --format=%p HEAD^)"
 '