Re: [PATCH v2 00/21] Prepare tests for reftable backend

> Rewrites some tests to avoid direct filesystem access.
>
> Introduces the test prereq REFFILES to mark other tests that depend on
> specifics of the files ref backend.
>
> changes in v2 (relative to v1 from Apr 19)
>
>  * t9300: use ref-store test-helper to read toplevel tag.
>  * t1401: use $TAR for restoring.
>  * t1407: clarify what test is doing.
>  * t1417: "$TAR" rather than tar
>  * t1415: clarify test objective.
>  * t7003: formatting.
>  * README entry for REFFILES.
>
> cc: SZEDER Gábor szeder.dev@gmail.com cc: Ævar Arnfjörð Bjarmason
> avarab@gmail.com cc: Han-Wen Nienhuys hanwen@google.com
>
> cc: Han-Wen Nienhuys hanwen@google.com
>
> Han-Wen Nienhuys (21):
>   t4202: split testcase for invalid HEAD symref and HEAD hash
>   t/helper/ref-store: initialize oid in resolve-ref
>   t9300: check ref existence using test-helper rather than a file system
>     check
>   t5601: read HEAD using rev-parse
>   t1401-symbolic-ref: avoid direct filesystem access
>   t1413: use tar to save and restore entire .git directory
>   t1301: fix typo in error message
>   t5000: reformat indentation to the latest fashion
>   t5000: inspect HEAD using git-rev-parse
>   t7003: use rev-parse rather than FS inspection
>   t5304: restyle: trim empty lines, drop ':' before >
>   t5304: use "reflog expire --all" to clear the reflog
>   test-lib: provide test prereq REFFILES
>   t1407: require REFFILES for for_each_reflog test
>   t1414: mark corruption test with REFFILES
>   t2017: mark --orphan/logAllRefUpdates=false test as REFFILES
>   t1404: mark tests that muck with .git directly as REFFILES.
>   t7900: mark pack-refs tests as REFFILES
>   t7003: check reflog existence only for REFFILES
>   t4202: mark bogus head hash test with REFFILES
>   t1415: set REFFILES for test specific to storage format
>
>  t/README                      |   6 ++
>  t/helper/test-ref-store.c     |   2 +-
>  t/t1301-shared-repo.sh        |   2 +-
>  t/t1401-symbolic-ref.sh       |  34 +++++-----
>  t/t1404-update-ref-errors.sh  |  30 ++++-----
>  t/t1407-worktree-ref-store.sh |   9 ++-
>  t/t1413-reflog-detach.sh      |   5 +-
>  t/t1414-reflog-walk.sh        |   2 +-
>  t/t1415-worktree-refs.sh      |   5 +-
>  t/t2017-checkout-orphan.sh    |   2 +-
>  t/t4202-log.sh                |  10 ++-
>  t/t5000-tar-tree.sh           | 113 +++++++++++++++++-----------------
>  t/t5304-prune.sh              |  83 ++++++++-----------------
>  t/t5601-clone.sh              |   3 +-
>  t/t7003-filter-branch.sh      |   7 ++-
>  t/t7900-maintenance.sh        |   2 +-
>  t/t9300-fast-import.sh        |   2 +-
>  t/test-lib.sh                 |   2 +
>  18 files changed, 156 insertions(+), 163 deletions(-)
>
>
> base-commit: 311531c9de557d25ac087c1637818bd2aad6eb3a
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1008%2Fhanwen%2Freffiles-v2
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1008/hanwen/reffiles-v2
> Pull-Request: https://github.com/git/git/pull/1008
>
> Range-diff vs v1:
>
>   1:  91ef012cbcc9 !  1:  8ad4a35cda70 t4202: split testcase for invalid HEAD symref and HEAD hash
>      @@ t/t4202-log.sh: test_expect_success 'log --graph --no-walk is forbidden' '
>       +	test_i18ngrep broken stderr'
>       +
>       +test_expect_success 'log diagnoses bogus HEAD symref' '
>      ++	rm -rf empty &&
>       +	git init empty &&
>       +	git --git-dir empty/.git symbolic-ref HEAD refs/heads/invalid.lock &&
>        	test_must_fail git -C empty log 2>stderr &&
>   -:  ------------ >  2:  e6222944a3eb t/helper/ref-store: initialize oid in resolve-ref
>   2:  ccc26a8950be !  3:  c5855b0caa73 t9300: check ref existence using git-rev-parse rather than FS check
>      @@ Metadata
>       Author: Han-Wen Nienhuys <hanwen@google.com>
>       
>        ## Commit message ##
>      -    t9300: check ref existence using git-rev-parse rather than FS check
>      +    t9300: check ref existence using test-helper rather than a file system check
>       
>           Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
>       
>      @@ t/t9300-fast-import.sh: test_expect_success 'B: accept branch name "TEMP_TAG"' '
>        		git prune" &&
>        	git fast-import <input &&
>       -	test -f .git/TEMP_TAG &&
>      -+	git rev-parse TEMP_TAG &&
>      ++	test $(test-tool ref-store main resolve-ref TEMP_TAG 0 | cut -f1 -d " " ) != "$ZERO_OID" &&
>        	test $(git rev-parse main) = $(git rev-parse TEMP_TAG^)
>        '
>        
>   3:  47b5ec56a383 =  4:  369c968ab837 t5601: read HEAD using rev-parse
>   4:  53cf1069552b !  5:  248d9ffe7927 t1401-symbolic-ref: avoid direct filesystem access
>      @@ Commit message
>           Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
>       
>        ## t/t1401-symbolic-ref.sh ##
>      -@@ t/t1401-symbolic-ref.sh: test_description='basic symbolic-ref tests'
>      - # the git repo, meaning that further tests will operate on
>      - # the surrounding git repo instead of the trash directory.
>      - reset_to_sane() {
>      --	echo ref: refs/heads/foo >.git/HEAD
>      -+	git --git-dir .git symbolic-ref HEAD refs/heads/foo
>      - }
>      +@@
>      + test_description='basic symbolic-ref tests'
>      + . ./test-lib.sh
>        
>      +-# If the tests munging HEAD fail, they can break detection of
>      +-# the git repo, meaning that further tests will operate on
>      +-# the surrounding git repo instead of the trash directory.
>      +-reset_to_sane() {
>      +-	echo ref: refs/heads/foo >.git/HEAD
>      +-}
>      +-
>       -test_expect_success 'symbolic-ref writes HEAD' '
>      --	git symbolic-ref HEAD refs/heads/foo &&
>      ++test_expect_success 'setup' '
>      + 	git symbolic-ref HEAD refs/heads/foo &&
>       -	echo ref: refs/heads/foo >expect &&
>       -	test_cmp expect .git/HEAD
>      --'
>      --
>      ++	test_commit file &&
>      ++	"$TAR" cf .git.tar .git/
>      + '
>      + 
>       -test_expect_success 'symbolic-ref reads HEAD' '
>       -	echo refs/heads/foo >expect &&
>      --	git symbolic-ref HEAD >actual &&
>      ++reset_to_sane() {
>      ++	rm -rf .git &&
>      ++	"$TAR" xf .git.tar
>      ++}
>      ++
>       +test_expect_success 'symbolic-ref read/write roundtrip' '
>       +	git symbolic-ref HEAD refs/heads/read-write-roundtrip &&
>      -+	echo refs/heads/read-write-roundtrip > expect &&
>      -+	git symbolic-ref HEAD > actual &&
>      ++	echo refs/heads/read-write-roundtrip >expect &&
>      + 	git symbolic-ref HEAD >actual &&
>        	test_cmp expect actual
>        '
>      +@@ t/t1401-symbolic-ref.sh: test_expect_success 'symbolic-ref reads HEAD' '
>      + test_expect_success 'symbolic-ref refuses non-ref for HEAD' '
>      + 	test_must_fail git symbolic-ref HEAD foo
>      + '
>      ++
>      + reset_to_sane
>      + 
>      + test_expect_success 'symbolic-ref refuses bare sha1' '
>      +-	echo content >file && git add file && git commit -m one &&
>      + 	test_must_fail git symbolic-ref HEAD $(git rev-parse HEAD)
>      + '
>      ++
>      + reset_to_sane
>        
>      + test_expect_success 'HEAD cannot be removed' '
>       @@ t/t1401-symbolic-ref.sh: reset_to_sane
>        test_expect_success 'symbolic-ref can be deleted' '
>        	git symbolic-ref NOTHEAD refs/heads/foo &&
>      @@ t/t1401-symbolic-ref.sh: reset_to_sane
>       -	test_path_is_file .git/refs/heads/foo &&
>       -	test_path_is_missing .git/NOTHEAD
>       +	git rev-parse refs/heads/foo &&
>      -+	! git symbolic-ref NOTHEAD
>      ++	test_must_fail git symbolic-ref NOTHEAD
>        '
>        reset_to_sane
>        
>      @@ t/t1401-symbolic-ref.sh: reset_to_sane
>        	git symbolic-ref -d NOTHEAD &&
>       -	test_path_is_missing .git/refs/heads/missing &&
>       -	test_path_is_missing .git/NOTHEAD
>      -+	! git rev-parse refs/heads/missing &&
>      -+	! git symbolic-ref NOTHEAD
>      ++	test_must_fail git rev-parse refs/heads/missing &&
>      ++	test_must_fail git symbolic-ref NOTHEAD
>        '
>        reset_to_sane
>        
>   5:  223583594c00 !  6:  e4e8fc1d4b4f t1413: use tar to save and restore entire .git directory
>      @@ t/t1413-reflog-detach.sh: export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
>        reset_state () {
>       -	git checkout main &&
>       -	cp saved_reflog .git/logs/HEAD
>      -+	rm -rf .git && tar -xf .git-saved.tar
>      ++	rm -rf .git && "$TAR" xf .git-saved.tar
>        }
>        
>        test_expect_success setup '
>      @@ t/t1413-reflog-detach.sh: test_expect_success setup '
>        	test_tick &&
>        	git commit --allow-empty -m second &&
>       -	cat .git/logs/HEAD >saved_reflog
>      -+	tar -cf .git-saved.tar .git
>      ++	"$TAR" cf .git-saved.tar .git
>        '
>        
>        test_expect_success baseline '
>   6:  70da8f5631d0 =  7:  89cc215c6014 t1301: fix typo in error message
>   -:  ------------ >  8:  e67b90847c4e t5000: reformat indentation to the latest fashion
>   7:  79843c0d5727 !  9:  d6072a70ae7d t5000: inspect HEAD using git-rev-parse
>      @@ Commit message
>           Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
>       
>        ## t/t5000-tar-tree.sh ##
>      -@@ t/t5000-tar-tree.sh: test_expect_success \
>      -      test_cmp expected.mtime b.mtime'
>      +@@ t/t5000-tar-tree.sh: test_expect_success 'validate file modification time' '
>      + 	test_cmp expected.mtime b.mtime
>      + '
>        
>      - test_expect_success \
>      +-test_expect_success \
>       -    'git get-tar-commit-id' \
>       -    'git get-tar-commit-id <b.tar >b.commitid &&
>       -     test_cmp .git/$(git symbolic-ref HEAD) b.commitid'
>      -+	'git get-tar-commit-id' \
>      -+	'git get-tar-commit-id <b.tar >actual &&
>      -+	git rev-parse HEAD > expect &&
>      -+	test_cmp expect actual'
>      ++test_expect_success 'git get-tar-commit-id' '
>      ++	git get-tar-commit-id <b.tar >actual &&
>      ++	git rev-parse HEAD >expect &&
>      ++	test_cmp expect actual
>      ++'
>        
>        test_expect_success 'git archive with --output, override inferred format' '
>        	git archive --format=tar --output=d4.zip HEAD &&
>   8:  dbb81b5b89d8 = 10:  4bf1bf16bca3 t7003: use rev-parse rather than FS inspection
>   -:  ------------ > 11:  6f15c15573af t5304: restyle: trim empty lines, drop ':' before >
>   9:  ba575839e422 ! 12:  d8e80d83b6f8 t5304: use "reflog expire --all" to clear the reflog
>      @@ Commit message
>       
>        ## t/t5304-prune.sh ##
>       @@ t/t5304-prune.sh: test_expect_success 'prune: prune nonsense parameters' '
>      - '
>        
>        test_expect_success 'prune: prune unreachable heads' '
>      --
>        	git config core.logAllRefUpdates false &&
>       -	mv .git/logs .git/logs.old &&
>      - 	: > file2 &&
>      +-	: > file2 &&
>      ++	>file2 &&
>        	git add file2 &&
>        	git commit -m temporary &&
>        	tmp_head=$(git rev-list -1 HEAD) &&
>      @@ t/t5304-prune.sh: test_expect_success 'prune: prune nonsense parameters' '
>       +	git reflog expire --all &&
>        	git prune &&
>        	test_must_fail git reset $tmp_head --
>      --
>        '
>      - 
>      +@@ t/t5304-prune.sh: test_expect_success 'prune: prune unreachable heads' '
>        test_expect_success 'prune: do not prune detached HEAD with no reflog' '
>      - 
>        	git checkout --detach --quiet &&
>        	git commit --allow-empty -m "detached commit" &&
>       -	# verify that there is no reflogs
>      @@ t/t5304-prune.sh: test_expect_success 'prune: prune nonsense parameters' '
>       +	git reflog expire --all &&
>        	git prune -n >prune_actual &&
>        	test_must_be_empty prune_actual
>      - 
>      -@@ t/t5304-prune.sh: test_expect_success 'prune: prune former HEAD after checking out branch' '
>      - 
>      + '
>      +@@ t/t5304-prune.sh: test_expect_success 'prune: do not prune detached HEAD with no reflog' '
>      + test_expect_success 'prune: prune former HEAD after checking out branch' '
>        	head_oid=$(git rev-parse HEAD) &&
>        	git checkout --quiet main &&
>       +	git reflog expire --all &&
>        	git prune -v >prune_actual &&
>        	grep "$head_oid" prune_actual
>      - 
>      + '
>  10:  3d3b733c3127 ! 13:  180847f4db14 test-lib: provide test prereq REFFILES
>      @@ Commit message
>       
>           Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
>       
>      + ## t/README ##
>      +@@ t/README: use these, and "test_set_prereq" for how to define your own.
>      + 
>      +    Git wasn't compiled with NO_PTHREADS=YesPlease.
>      + 
>      ++ - REFFILES
>      ++
>      ++   Test is specific to packed/loose ref storage, and should be
>      ++   disabled for other ref storage backends
>      ++
>      ++
>      + Tips for Writing Tests
>      + ----------------------
>      + 
>      +
>        ## t/test-lib.sh ##
>       @@ t/test-lib.sh: parisc* | hppa*)
>        	;;
>  11:  dd1f6969c28d ! 14:  f3307b62bfd7 t1407: require REFFILES for for_each_reflog test
>      @@ Metadata
>        ## Commit message ##
>           t1407: require REFFILES for for_each_reflog test
>       
>      -    It tries to setup a reflog by catting to .git/logs/
>      +    Add extensive comment why this test needs a REFFILES annotation.
>      +
>      +    I tried forcing universal reflog creation with core.logAllRefUpdates=true, but
>      +    that apparently also doesn't cause reflogs to be created for pseudorefs
>       
>           Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
>       
>      @@ t/t1407-worktree-ref-store.sh: test_expect_success 'create_symref(FOO, refs/head
>        '
>        
>       -test_expect_success 'for_each_reflog()' '
>      ++# Some refs (refs/bisect/*, pseudorefs) are kept per worktree, so they should
>      ++# only appear in the for-each-reflog output if it is called from the correct
>      ++# worktree, which is exercised in this test. This test is poorly written (and
>      ++# therefore marked REFFILES) for mulitple reasons: 1) it creates invalidly
>      ++# formatted log entres. 2) it uses direct FS access for creating the reflogs. 3)
>      ++# PSEUDO-WT and refs/bisect/random do not create reflogs by default, so it is
>      ++# not testing a realistic scenario.
>       +test_expect_success REFFILES 'for_each_reflog()' '
>        	echo $ZERO_OID > .git/logs/PSEUDO-MAIN &&
>        	mkdir -p     .git/logs/refs/bisect &&
>  12:  86951eb39cb6 = 15:  0d3b18cd3542 t1414: mark corruption test with REFFILES
>  13:  1ce545043846 = 16:  b64e3e7ade15 t2017: mark --orphan/logAllRefUpdates=false test as REFFILES
>  14:  a3abc4f70e7d ! 17:  fcc2b714dd50 t1404: mark tests that muck with .git directly as REFFILES.
>      @@ Metadata
>        ## Commit message ##
>           t1404: mark tests that muck with .git directly as REFFILES.
>       
>      +    The packed/loose ref storage is an overlay combination of packed-refs (refs and
>      +    tags in a single file) and one-file-per-ref. This creates all kinds of edge
>      +    cases related to directory/file conflicts, (non-)empty directories, and the
>      +    locking scheme, none of which applies to reftable.
>      +
>           Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
>       
>        ## t/t1404-update-ref-errors.sh ##
>  15:  2b3021c4ba62 ! 18:  ff3b67c84c41 t7900: mark pack-refs tests as REFFILES
>      @@ Metadata
>        ## Commit message ##
>           t7900: mark pack-refs tests as REFFILES
>       
>      +    Reftable automatically compacts tables on writes. The functionality of
>      +    incremental compaction is unittested in reftable/stack_test.c
>      +    (test_reftable_stack_auto_compaction)
>      +
>      +    In addition, pack-refs triggers a full compaction of the entire stack. This is
>      +    exercised in t0031-reftable.sh.
>      +
>      +    Given that git-maintenance simply calls out git-pack-refs, it seems superfluous
>      +    to test this further for reftable.
>      +
>           Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
>       
>        ## t/t7900-maintenance.sh ##
>  16:  a5b9439192db ! 19:  24dcf05d8fa6 t7003: check reflog existence only for REFFILES
>      @@ t/t7003-filter-branch.sh: test_expect_success '--prune-empty is able to prune en
>        	git filter-branch -f --prune-empty --index-filter "git update-index --remove A.t B.t" prune-entire &&
>        	test_must_fail git rev-parse refs/heads/prune-entire &&
>       -	test_must_fail git reflog exists refs/heads/prune-entire
>      -+	if test_have_prereq REFFILES ; then
>      ++	if test_have_prereq REFFILES
>      ++	then
>       +		test_must_fail git reflog exists refs/heads/prune-entire
>       +	fi
>        '
>  17:  a2cce772d44f = 20:  a33cdfda74ff t4202: mark bogus head hash test with REFFILES
>  18:  0665edb1308b ! 21:  d7e5de8dba46 t1415: set REFFILES for test specific to storage format
>      @@ Metadata
>        ## Commit message ##
>           t1415: set REFFILES for test specific to storage format
>       
>      +    Packing refs (and therefore checking that certain refs are not packed) is a
>      +    property of the packed/loose ref storage. Add a comment to explain what the test
>      +    checks.
>      +
>           Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
>       
>        ## t/t1415-worktree-refs.sh ##
>      @@ t/t1415-worktree-refs.sh: test_expect_success 'setup' '
>        '
>        
>       -test_expect_success 'refs/worktree must not be packed' '
>      ++# The 'packed-refs' files is stored directly in .git/. This means it is global
>      ++# to the repository, and can only contain refs that are shared across all
>      ++# worktrees.
>       +test_expect_success REFFILES 'refs/worktree must not be packed' '
>        	git pack-refs --all &&
>        	test_path_is_missing .git/refs/tags/wt1 &&