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8 commits

Author SHA1 Message Date
Junio C Hamano deb67d12de Merge branch 'jx/fetch-atomic-error-message-fix'
"git fetch --atomic" issued an unnecessary empty error message,
which has been corrected.

* jx/fetch-atomic-error-message-fix:
  fetch: no redundant error message for atomic fetch
  t5574: test porcelain output of atomic fetch
2023-12-27 14:52:27 -08:00
Jiang Xin 18ce48918c fetch: no redundant error message for atomic fetch
If an error occurs during an atomic fetch, a redundant error message
will appear at the end of do_fetch(). It was introduced in b3a804663c
(fetch: make `--atomic` flag cover backfilling of tags, 2022-02-17).

Because a failure message is displayed before setting retcode in the
function do_fetch(), calling error() on the err message at the end of
this function may result in redundant or empty error message to be
displayed.

We can remove the redundant error() function, because we know that
the function ref_transaction_abort() never fails. While we can find a
common pattern for calling ref_transaction_abort() by running command
"git grep -A1 ref_transaction_abort", e.g.:

    if (ref_transaction_abort(transaction, &error))
        error("abort: %s", error.buf);

Following this pattern, we can tolerate the return value of the function
ref_transaction_abort() being changed in the future. We also delay the
output of the err message to the end of do_fetch() to reduce redundant
code. With these changes, the test case "fetch porcelain output
(atomic)" in t5574 will also be fixed.

Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-12-18 08:30:33 -08:00
Jiang Xin 97d82b2963 t5574: test porcelain output of atomic fetch
The test case "fetch porcelain output" checks output of the fetch
command. The error output must be empty with the follow assertion:

    test_must_be_empty stderr

But this assertion fails if using atomic fetch. Refactor this test case
to use different fetch options by splitting it into three test cases.

  1. "setup for fetch porcelain output".

  2. "fetch porcelain output": for non-atomic fetch.

  3. "fetch porcelain output (atomic)": for atomic fetch.

Add new command "test_commit ..." in the first test case, so that if we
run these test cases individually (--run=4-6), "git rev-parse HEAD~"
command will work properly. Run the above test cases, we can find that
one test case has a known breakage, as shown below:

    ok 4 - setup for fetch porcelain output
    ok 5 - fetch porcelain output  # TODO known breakage vanished
    not ok 6 - fetch porcelain output (atomic) # TODO known breakage

The failed test case has an error message with only the error prompt but
no message body, as follows:

    'stderr' is not empty, it contains:
    error:

In a later commit, we will fix this issue.

Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-12-18 08:30:32 -08:00
Junio C Hamano 6789275d37 tests: teach callers of test_i18ngrep to use test_grep
They are equivalents and the former still exists, so as long as the
only change this commit makes are to rewrite test_i18ngrep to
test_grep, there won't be any new bug, even if there still are
callers of test_i18ngrep remaining in the tree, or when merged to
other topics that add new uses of test_i18ngrep.

This patch was produced more or less with

    git grep -l -e 'test_i18ngrep ' 't/t[0-9][0-9][0-9][0-9]-*.sh' |
    xargs perl -p -i -e 's/test_i18ngrep /test_grep /'

and a good way to sanity check the result yourself is to run the
above in a checkout of c4603c1c (test framework: further deprecate
test_i18ngrep, 2023-10-31) and compare the resulting working tree
contents with the result of applying this patch to the same commit.
You'll see that test_i18ngrep in a few t/lib-*.sh files corrected,
in addition to the manual reproduction.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-11-02 17:13:44 +09:00
Patrick Steinhardt dd781e3856 fetch: introduce machine-parseable "porcelain" output format
The output of git-fetch(1) is obviously designed for consumption by
users, only: we neatly columnize data, we abbreviate reference names, we
print neat arrows and we don't provide information about actual object
IDs that have changed. This makes the output format basically unusable
in the context of scripted invocations of git-fetch(1) that want to
learn about the exact changes that the command performs.

Introduce a new machine-parseable "porcelain" output format that is
supposed to fix this shortcoming. This output format is intended to
provide information about every reference that is about to be updated,
the old object ID that the reference has been pointing to and the new
object ID it will be updated to. Furthermore, the output format provides
the same flags as the human-readable format to indicate basic conditions
for each reference update like whether it was a fast-forward update, a
branch deletion, a rejected update or others.

The output format is quite simple:

```
<flag> <old-object-id> <new-object-id> <local-reference>\n
```

We assume two conditions which are generally true:

    - The old and new object IDs have fixed known widths and cannot
      contain spaces.

    - References cannot contain newlines.

With these assumptions, the output format becomes unambiguously
parseable. Furthermore, given that this output is designed to be
consumed by scripts, the machine-readable data is printed to stdout
instead of stderr like the human-readable output is. This is mostly done
so that other data printed to stderr, like error messages or progress
meters, don't interfere with the parseable data.

A notable ommission here is that the output format does not include the
remote from which a reference was fetched, which might be important
information especially in the context of multi-remote fetches. But as
such a format would require us to print the remote for every single
reference update due to parallelizable fetches it feels wasteful for the
most likely usecase, which is when fetching from a single remote.

In a similar spirit, a second restriction is that this cannot be used
with `--recurse-submodules`. This is because any reference updates would
be ambiguous without also printing the repository in which the update
happens.

Considering that both multi-remote and submodule fetches are user-facing
features, using them in conjunction with `--porcelain` that is intended
for scripting purposes is likely not going to be useful in the majority
of cases. With that in mind these restrictions feel acceptable. If
usecases for either of these come up in the future though it is easy
enough to add a new "porcelain-v2" format that adds this information.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-05-10 10:35:25 -07:00
Patrick Steinhardt 1c31764dda fetch: print left-hand side when fetching HEAD:foo
`store_updated_refs()` parses the remote reference for two purposes:

    - It gets used as a note when writing FETCH_HEAD.

    - It is passed through to `display_ref_update()` to display
      updated references in the following format:

      ```
       * branch               master          -> master
      ```

In most cases, the parsed remote reference is the prettified reference
name and can thus be used for both cases. But if the remote reference is
HEAD, the parsed remote reference becomes empty. This is intended when
we write the FETCH_HEAD, where we skip writing the note in that case.
But when displaying the updated references this leads to inconsistent
output where the left-hand side of reference updates is missing in some
cases:

```
$ git fetch origin HEAD HEAD:explicit-head :implicit-head main
From https://github.com/git/git
 * branch                  HEAD       -> FETCH_HEAD
 * [new ref]                          -> explicit-head
 * [new ref]                          -> implicit-head
 * branch                  main       -> FETCH_HEAD
```

This behaviour has existed ever since the table-based output has been
introduced for git-fetch(1) via 165f390250 (git-fetch: more terse fetch
output, 2007-11-03) and was never explicitly documented either in the
commit message or in any of our tests. So while it may not be a bug per
se, it feels like a weird inconsistency and not like it was a concious
design decision.

The logic of how we compute the remote reference name that we ultimately
pass to `display_ref_update()` is not easy to follow. There are three
different cases here:

    - When the remote reference name is "HEAD" we set the remote
      reference name to the empty string. This is the case that causes
      the left-hand side to go missing, where we would indeed want to
      print "HEAD" instead of the empty string. This is what
      `prettify_refname()` would return.

    - When the remote reference name has a well-known prefix then we
      strip this prefix. This matches what `prettify_refname()` does.

    - Otherwise, we keep the fully qualified reference name. This also
      matches what `prettify_refname()` does.

As the return value of `prettify_refname()` would do the correct thing
for us in all three cases, we can thus fix the inconsistency by passing
through the full remote reference name to `display_ref_update()`, which
learns to call `prettify_refname()`. At the same time, this also
simplifies the code a bit.

Note that this patch also changes formatting of the block that computes
the "kind" (which is the category like "branch" or "tag") and "what"
(which is the prettified reference name like "master" or "v1.0")
variables. This is done on purpose so that it is part of the diff,
hopefully making the change easier to comprehend.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-05-10 10:35:25 -07:00
Patrick Steinhardt 3daf6558ed fetch: add a test to exercise invalid output formats
Add a testcase that exercises the logic when an invalid output format is
passed via the `fetch.output` configuration.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-05-10 10:35:24 -07:00
Patrick Steinhardt 2c5691d6cf fetch: split out tests for output format
We're about to introduce a new porcelain mode for the output of
git-fetch(1). As part of that we'll be introducing a set of new tests
that only relate to the output of this command.

Split out tests that exercise the output format of git-fetch(1) so that
it becomes easier to verify this functionality as a standalone unit. As
the tests assume that the default branch is called "main" we set up the
corresponding GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME environment variable
accordingly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-05-10 10:35:24 -07:00