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414 commits

Author SHA1 Message Date
Junio C Hamano 644f4a2046 Merge branch 'jt/push-negotiation'
"git push" learns to discover common ancestor with the receiving
end over protocol v2.

* jt/push-negotiation:
  send-pack: support push negotiation
  fetch: teach independent negotiation (no packfile)
  fetch-pack: refactor command and capability write
  fetch-pack: refactor add_haves()
  fetch-pack: refactor process_acks()
2021-05-16 21:05:22 +09:00
Jonathan Tan 9c1e657a8f fetch: teach independent negotiation (no packfile)
Currently, the packfile negotiation step within a Git fetch cannot be
done independent of sending the packfile, even though there is at least
one application wherein this is useful. Therefore, make it possible for
this negotiation step to be done independently. A subsequent commit will
use this for one such application - push negotiation.

This feature is for protocol v2 only. (An implementation for protocol v0
would require a separate implementation in the fetch, transport, and
transport helper code.)

In the protocol, the main hindrance towards independent negotiation is
that the server can unilaterally decide to send the packfile. This is
solved by a "wait-for-done" argument: the server will then wait for the
client to say "done". In practice, the client will never say it; instead
it will cease requests once it is satisfied.

In the client, the main change lies in the transport and transport
helper code. fetch_refs_via_pack() performs everything needed - protocol
version and capability checks, and the negotiation itself.

There are 2 code paths that do not go through fetch_refs_via_pack() that
needed to be individually excluded: the bundle transport (excluded
through requiring smart_options, which the bundle transport doesn't
support) and transport helpers that do not support takeover. If or when
we support independent negotiation for protocol v0, we will need to
modify these 2 code paths to support it. But for now, report failure if
independent negotiation is requested in these cases.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-05 10:41:29 +09:00
Derrick Stolee 2e03115d0c fetch: add --prefetch option
The --prefetch option will be used by the 'prefetch' maintenance task
instead of sending refspecs explicitly across the command-line. The
intention is to modify the refspec to place all results in
refs/prefetch/ instead of anywhere else.

Create helper method filter_prefetch_refspec() to modify a given refspec
to fit the rules expected of the prefetch task:

 * Negative refspecs are preserved.
 * Refspecs without a destination are removed.
 * Refspecs whose source starts with "refs/tags/" are removed.
 * Other refspecs are placed within "refs/prefetch/".

Finally, we add the 'force' option to ensure that prefetch refs are
replaced as necessary.

There are some interesting cases that are worth testing.

An earlier version of this change dropped the "i--" from the loop that
deletes a refspec item and shifts the remaining entries down. This
allowed some refspecs to not be modified. The subtle part about the
first --prefetch test is that the "refs/tags/*" refspec appears directly
before the "refs/heads/bogus/*" refspec. Without that "i--", this
ordering would remove the "refs/tags/*" refspec and leave the last one
unmodified, placing the result in "refs/heads/*".

It is possible to have an empty refspec. This is typically the case for
remotes other than the origin, where users want to fetch a specific tag
or branch. To correctly test this case, we need to further remove the
upstream remote for the local branch. Thus, we are testing a refspec
that will be deleted, leaving nothing to fetch.

Helped-by: Tom Saeger <tom.saeger@oracle.com>
Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-16 13:36:55 -07:00
Junio C Hamano 69571dfe21 Merge branch 'jt/clone-unborn-head'
"git clone" tries to locally check out the branch pointed at by
HEAD of the remote repository after it is done, but the protocol
did not convey the information necessary to do so when copying an
empty repository.  The protocol v2 learned how to do so.

* jt/clone-unborn-head:
  clone: respect remote unborn HEAD
  connect, transport: encapsulate arg in struct
  ls-refs: report unborn targets of symrefs
2021-02-17 17:21:40 -08:00
Jonathan Tan 39835409d1 connect, transport: encapsulate arg in struct
In a future patch we plan to return the name of an unborn current branch
from deep in the callchain to a caller via a new pointer parameter that
points at a variable in the caller when the caller calls
get_remote_refs() and transport_get_remote_refs().

In preparation for that, encapsulate the existing ref_prefixes
parameter into a struct. The aforementioned unborn current branch will
go into this new struct in the future patch.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-05 13:49:54 -08:00
Patrick Steinhardt c7b190dabd fetch: implement support for atomic reference updates
When executing a fetch, then git will currently allocate one reference
transaction per reference update and directly commit it. This means that
fetches are non-atomic: even if some of the reference updates fail,
others may still succeed and modify local references.

This is fine in many scenarios, but this strategy has its downsides.

- The view of remote references may be inconsistent and may show a
  bastardized state of the remote repository.

- Batching together updates may improve performance in certain
  scenarios. While the impact probably isn't as pronounced with loose
  references, the upcoming reftable backend may benefit as it needs to
  write less files in case the update is batched.

- The reference-update hook is currently being executed twice per
  updated reference. While this doesn't matter when there is no such
  hook, we have seen severe performance regressions when doing a
  git-fetch(1) with reference-transaction hook when the remote
  repository has hundreds of thousands of references.

Similar to `git push --atomic`, this commit thus introduces atomic
fetches. Instead of allocating one reference transaction per updated
reference, it causes us to only allocate a single transaction and commit
it as soon as all updates were received. If locking of any reference
fails, then we abort the complete transaction and don't update any
reference, which gives us an all-or-nothing fetch.

Note that this may not completely fix the first of above downsides, as
the consistent view also depends on the server-side. If the server
doesn't have a consistent view of its own references during the
reference negotiation phase, then the client would get the same
inconsistent view the server has. This is a separate problem though and,
if it actually exists, can be fixed at a later point.

This commit also changes the way we write FETCH_HEAD in case `--atomic`
is passed. Instead of writing changes as we go, we need to accumulate
all changes first and only commit them at the end when we know that all
reference updates succeeded. Ideally, we'd just do so via a temporary
file so that we don't need to carry all updates in-memory. This isn't
trivially doable though considering the `--append` mode, where we do not
truncate the file but simply append to it. And given that we support
concurrent processes appending to FETCH_HEAD at the same time without
any loss of data, seeding the temporary file with current contents of
FETCH_HEAD initially and then doing a rename wouldn't work either. So
this commit implements the simple strategy of buffering all changes and
appending them to the file on commit.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12 12:06:15 -08:00
Patrick Steinhardt d4c8db8f1b fetch: allow passing a transaction to s_update_ref()
The handling of ref updates is completely handled by `s_update_ref()`,
which will manage the complete lifecycle of the reference transaction.
This is fine right now given that git-fetch(1) does not support atomic
fetches, so each reference gets its own transaction. It is quite
inflexible though, as `s_update_ref()` only knows about a single
reference update at a time, so it doesn't allow us to alter the
strategy.

This commit prepares `s_update_ref()` and its only caller
`update_local_ref()` to allow passing an external transaction. If none
is given, then the existing behaviour is triggered which creates a new
transaction and directly commits it. Otherwise, if the caller provides a
transaction, then we only queue the update but don't commit it. This
optionally allows the caller to manage when a transaction will be
committed.

Given that `update_local_ref()` is always called with a `NULL`
transaction for now, no change in behaviour is expected from this
change.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12 12:06:15 -08:00
Patrick Steinhardt c45889f104 fetch: refactor s_update_ref to use common exit path
The cleanup code in `s_update_ref()` is currently duplicated for both
succesful and erroneous exit paths. This commit refactors the function
to have a shared exit path for both cases to remove the duplication.

Suggested-by: Christian Couder <christian.couder@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12 12:06:15 -08:00
Patrick Steinhardt 929d044575 fetch: use strbuf to format FETCH_HEAD updates
This commit refactors `append_fetch_head()` to use a `struct strbuf` for
formatting the update which we're about to append to the FETCH_HEAD
file. While the refactoring doesn't have much of a benefit right now, it
serves as a preparatory step to implement atomic fetches where we need
to buffer all updates to FETCH_HEAD and only flush them out if all
reference updates succeeded.

No change in behaviour is expected from this commit.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12 12:06:14 -08:00
Patrick Steinhardt 58a646a368 fetch: extract writing to FETCH_HEAD
When performing a fetch with the default `--write-fetch-head` option, we
write all updated references to FETCH_HEAD while the updates are
performed. Given that updates are not performed atomically, it means
that we we write to FETCH_HEAD even if some or all of the reference
updates fail.

Given that we simply update FETCH_HEAD ad-hoc with each reference, the
logic is completely contained in `store_update_refs` and thus quite hard
to extend. This can already be seen by the way we skip writing to the
FETCH_HEAD: instead of having a conditional which simply skips writing,
we instead open "/dev/null" and needlessly write all updates there.

We are about to extend git-fetch(1) to accept an `--atomic` flag which
will make the fetch an all-or-nothing operation with regards to the
reference updates. This will also require us to make the updates to
FETCH_HEAD an all-or-nothing operation, but as explained doing so is not
easy with the current layout. This commit thus refactors the wa we write
to FETCH_HEAD and pulls out the logic to open, append to, commit and
close the file. While this may seem rather over-the top at first,
pulling out this logic will make it a lot easier to update the code in a
subsequent commit. It also allows us to easily skip writing completely
in case `--no-write-fetch-head` was passed.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12 12:06:14 -08:00
Elijah Newren 6da1a25814 hashmap: provide deallocation function names
hashmap_free(), hashmap_free_entries(), and hashmap_free_() have existed
for a while, but aren't necessarily the clearest names, especially with
hashmap_partial_clear() being added to the mix and lazy-initialization
now being supported.  Peff suggested we adopt the following names[1]:

  - hashmap_clear() - remove all entries and de-allocate any
    hashmap-specific data, but be ready for reuse

  - hashmap_clear_and_free() - ditto, but free the entries themselves

  - hashmap_partial_clear() - remove all entries but don't deallocate
    table

  - hashmap_partial_clear_and_free() - ditto, but free the entries

This patch provides the new names and converts all existing callers over
to the new naming scheme.

[1] https://lore.kernel.org/git/20201030125059.GA3277724@coredump.intra.peff.net/

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-02 12:15:50 -08:00
Junio C Hamano 8e3ec76a20 Merge branch 'jk/refspecs-negative'
"git fetch" and "git push" support negative refspecs.

* jk/refspecs-negative:
  refspec: add support for negative refspecs
2020-10-05 14:01:54 -07:00
Junio C Hamano e68f0a4e57 Merge branch 'jt/keep-partial-clone-filter-upon-lazy-fetch'
The lazy fetching done internally to make missing objects available
in a partial clone incorrectly made permanent damage to the partial
clone filter in the repository, which has been corrected.

* jt/keep-partial-clone-filter-upon-lazy-fetch:
  fetch: do not override partial clone filter
  promisor-remote: remove unused variable
2020-10-05 14:01:53 -07:00
Jacob Keller c0192df630 refspec: add support for negative refspecs
Both fetch and push support pattern refspecs which allow fetching or
pushing references that match a specific pattern. Because these patterns
are globs, they have somewhat limited ability to express more complex
situations.

For example, suppose you wish to fetch all branches from a remote except
for a specific one. To allow this, you must setup a set of refspecs
which match only the branches you want. Because refspecs are either
explicit name matches, or simple globs, many patterns cannot be
expressed.

Add support for a new type of refspec, referred to as "negative"
refspecs. These are prefixed with a '^' and mean "exclude any ref
matching this refspec". They can only have one "side" which always
refers to the source. During a fetch, this refers to the name of the ref
on the remote. During a push, this refers to the name of the ref on the
local side.

With negative refspecs, users can express more complex patterns. For
example:

 git fetch origin refs/heads/*:refs/remotes/origin/* ^refs/heads/dontwant

will fetch all branches on origin into remotes/origin, but will exclude
fetching the branch named dontwant.

Refspecs today are commutative, meaning that order doesn't expressly
matter. Rather than forcing an implied order, negative refspecs will
always be applied last. That is, in order to match, a ref must match at
least one positive refspec, and match none of the negative refspecs.
This is similar to how negative pathspecs work.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-30 14:52:00 -07:00
Jonathan Tan 23547c4051 fetch: do not override partial clone filter
When a fetch with the --filter argument is made, the configured default
filter is set even if one already exists. This change was made in
5e46139376 ("builtin/fetch: remove unique promisor remote limitation",
2019-06-25) - in particular, changing from:

 * If this is the FIRST partial-fetch request, we enable partial
 * on this repo and remember the given filter-spec as the default
 * for subsequent fetches to this remote.

to:

 * If this is a partial-fetch request, we enable partial on
 * this repo if not already enabled and remember the given
 * filter-spec as the default for subsequent fetches to this
 * remote.

(The given filter-spec is "remembered" even if there is already an
existing one.)

This is problematic whenever a lazy fetch is made, because lazy fetches
are made using "git fetch --filter=blob:none", but this will also happen
if the user invokes "git fetch --filter=<filter>" manually. Therefore,
restore the behavior prior to 5e46139376, which writes a filter-spec
only if the current fetch request is the first partial-fetch one (for
that remote).

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-28 16:11:59 -07:00
Junio C Hamano 48794acc50 Merge branch 'ds/maintenance-part-1'
A "git gc"'s big brother has been introduced to take care of more
repository maintenance tasks, not limited to the object database
cleaning.

* ds/maintenance-part-1:
  maintenance: add trace2 regions for task execution
  maintenance: add auto condition for commit-graph task
  maintenance: use pointers to check --auto
  maintenance: create maintenance.<task>.enabled config
  maintenance: take a lock on the objects directory
  maintenance: add --task option
  maintenance: add commit-graph task
  maintenance: initialize task array
  maintenance: replace run_auto_gc()
  maintenance: add --quiet option
  maintenance: create basic maintenance runner
2020-09-25 15:25:38 -07:00
Junio C Hamano 6854689e65 Merge branch 'ar/fetch-ipversion-in-all'
"git fetch --all --ipv4/--ipv6" forgot to pass the protocol options
to instances of the "git fetch" that talk to individual remotes,
which has been corrected.

* ar/fetch-ipversion-in-all:
  fetch: pass --ipv4 and --ipv6 options to sub-fetches
2020-09-22 12:36:34 -07:00
Junio C Hamano bcb68bff80 Merge branch 'os/fetch-submodule-optim'
Optimization around submodule handling.

* os/fetch-submodule-optim:
  fetch: do not look for submodule changes in unchanged refs
2020-09-22 12:36:28 -07:00
Derrick Stolee a95ce12430 maintenance: replace run_auto_gc()
The run_auto_gc() method is used in several places to trigger a check
for repo maintenance after some Git commands, such as 'git commit' or
'git fetch'.

To allow for extra customization of this maintenance activity, replace
the 'git gc --auto [--quiet]' call with one to 'git maintenance run
--auto [--quiet]'. As we extend the maintenance builtin with other
steps, users will be able to select different maintenance activities.

Rename run_auto_gc() to run_auto_maintenance() to be clearer what is
happening on this call, and to expose all callers in the current diff.
Rewrite the method to use a struct child_process to simplify the calls
slightly.

Since 'git fetch' already allows disabling the 'git gc --auto'
subprocess, add an equivalent option with a different name to be more
descriptive of the new behavior: '--[no-]maintenance'. Update the
documentation to include these options at the same time.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Alex Riesen 4e735c1326 fetch: pass --ipv4 and --ipv6 options to sub-fetches
The options indicate user intent for the whole fetch operation, and
ignoring them in sub-fetches (i.e. "--all" and recursive fetching of
submodules) is quite unexpected when, for instance, it is intended
to limit all of the communication to a specific transport protocol
for some reason.

Signed-off-by: Alex Riesen <alexander.riesen@cetitec.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-15 14:15:05 -07:00
René Scharfe 1af8b8c0a5 refspec: add and use refspec_appendf()
Add a function for building a refspec using printf-style formatting.  It
frees callers from managing their own buffer.  Use it throughout the
tree to shorten and simplify its callers.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-06 13:15:46 -07:00
Orgad Shaneh 7ea0c2f44d fetch: do not look for submodule changes in unchanged refs
When fetching recursively with submodules, for each ref in the
superproject, we call check_for_new_submodule_commits() which collects all
the objects that have to be checked for submodule changes on
calculate_changed_submodule_paths(). On the first call, it also collects all
the existing refs for excluding them from the scan.

calculate_changed_submodule_paths() creates an argument array with all the
collected new objects, followed by --not and all the old objects. This argv
is passed to setup_revisions, which parses each argument, converts it back
to an oid and resolves the object. The parsing itself also does redundant
work, because it is treated like user input, while in fact it is a full
oid. So it needlessly attempts to look it up as ref (checks if it has ^, ~
etc.), checks if it is a file name etc.

For a repository with many refs, all of this is expensive. But if the fetch
in the superproject did not update the ref (i.e. the objects that are
required to exist in the submodule did not change), there is no need to
include it in the list.

Before commit be76c212 (fetch: ensure submodule objects fetched,
2018-12-06), submodule reference changes were only detected for refs that
were changed, but not for new refs. This commit covered also this case, but
what it did was to just include every ref.

This change should reduce the number of scanned refs by about half (except
the case of a no-op fetch, which will not scan any ref), because all the
existing refs will still be listed after --not.

The regression was reported here:
https://public-inbox.org/git/CAGHpTBKSUJzFSWc=uznSu2zB33qCSmKXM-
iAjxRCpqNK5bnhRg@mail.gmail.com/

Signed-off-by: Orgad Shaneh <orgads@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-06 09:50:49 -07:00
Junio C Hamano b4100f366c Merge branch 'jt/lazy-fetch'
Updates to on-demand fetching code in lazily cloned repositories.

* jt/lazy-fetch:
  fetch: no FETCH_HEAD display if --no-write-fetch-head
  fetch-pack: remove no_dependents code
  promisor-remote: lazy-fetch objects in subprocess
  fetch-pack: do not lazy-fetch during ref iteration
  fetch: only populate existing_refs if needed
  fetch: avoid reading submodule config until needed
  fetch: allow refspecs specified through stdin
  negotiator/noop: add noop fetch negotiator
2020-09-03 12:37:04 -07:00
Jonathan Tan db3c293ecd fetch: no FETCH_HEAD display if --no-write-fetch-head
887952b8c6 ("fetch: optionally allow disabling FETCH_HEAD update",
2020-08-18) introduced the ability to disable writing to FETCH_HEAD
during fetch, but did not suppress the "<source> -> FETCH_HEAD" message
when this ability is used. This message is misleading in this case,
because FETCH_HEAD is not written. Also, because "fetch" is used to
lazy-fetch missing objects in a partial clone, this significantly
clutters up the output in that case since the objects to be fetched are
potentially numerous.

Therefore, suppress this message when --no-write-fetch-head is passed
(but not when --dry-run is set).

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-02 14:26:55 -07:00
Junio C Hamano 0d9a8e33f9 Merge branch 'jk/leakfix'
Code clean-up.

* jk/leakfix:
  submodule--helper: fix leak of core.worktree value
  config: fix leak in git_config_get_expiry_in_days()
  config: drop git_config_get_string_const()
  config: fix leaks from git_config_get_string_const()
  checkout: fix leak of non-existent branch names
  submodule--helper: use strbuf_release() to free strbufs
  clear_pattern_list(): clear embedded hashmaps
2020-08-27 14:04:49 -07:00
Jonathan Tan abcb7eeb31 fetch: only populate existing_refs if needed
In "fetch", get_ref_map() iterates over all refs to populate
"existing_refs" in order to populate peer_ref->old_oid in the returned
refmap, even if the refmap has no peer_ref set - which is the case when
only literal hashes (i.e. no refs by name) are fetched.

Iterating over refs causes the targets of those refs to be checked for
existence. Avoiding this is especially important when we use "git fetch"
to perform lazy fetches in a partial clone because a target of such a
ref may need to be itself lazy-fetched (and otherwise causing an
infinite loop).

Therefore, avoid populating "existing_refs" until necessary. With this
patch, because Git lazy-fetches objects by literal hashes (to be done in
a subsequent commit), it will then be able to guarantee avoiding reading
targets of refs.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-18 13:25:05 -07:00
Jonathan Tan e5b942136e fetch: avoid reading submodule config until needed
In "fetch", there are two parameters submodule_fetch_jobs_config and
recurse_submodules that can be set in a variety of ways: through
.gitmodules, through .git/config, and through the command line.
Currently "fetch" handles this by first reading .gitmodules, then
reading .git/config (allowing it to overwrite existing values), then
reading the command line (allowing it to overwrite existing values).

Notice that we can avoid reading .gitmodules if .git/config and/or the
command line already provides us with what we need. In addition, if
recurse_submodules is found to be "no", we do not need the value of
submodule_fetch_jobs_config.

Avoiding reading .gitmodules is especially important when we use "git
fetch" to perform lazy fetches in a partial clone because the
.gitmodules file itself might need to be lazy fetched (and otherwise
causing an infinite loop).

In light of all this, avoid reading .gitmodules until necessary. When
reading it, we may only need one of the two parameters it provides, so
teach fetch_config_from_gitmodules() to support NULL arguments. With
this patch, users (including Git itself when invoking "git fetch" to
lazy-fetch) will be able to guarantee avoiding reading .gitmodules by
passing --recurse-submodules=no.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-18 13:25:05 -07:00
Jonathan Tan 2b713c272c fetch: allow refspecs specified through stdin
In a subsequent patch, partial clones will be taught to fetch missing
objects using a "git fetch" subprocess. Because the number of objects
fetched may be too numerous to fit on the command line, teach "fetch" to
accept refspecs passed through stdin.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-18 13:25:05 -07:00
Junio C Hamano 887952b8c6 fetch: optionally allow disabling FETCH_HEAD update
If you run fetch but record the result in remote-tracking branches,
and either if you do nothing with the fetched refs (e.g. you are
merely mirroring) or if you always work from the remote-tracking
refs (e.g. you fetch and then merge origin/branchname separately),
you can get away with having no FETCH_HEAD at all.

Teach "git fetch" a command line option "--[no-]write-fetch-head".
The default is to write FETCH_HEAD, and the option is primarily
meant to be used with the "--no-" prefix to override this default,
because there is no matching fetch.writeFetchHEAD configuration
variable to flip the default to off (in which case, the positive
form may become necessary to defeat it).

Note that under "--dry-run" mode, FETCH_HEAD is never written;
otherwise you'd see list of objects in the file that you do not
actually have.  Passing `--write-fetch-head` does not force `git
fetch` to write the file.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-18 12:56:57 -07:00
Jeff King f1de981e8b config: fix leaks from git_config_get_string_const()
There are two functions to get a single config string:

  - git_config_get_string()

  - git_config_get_string_const()

One might naively think that the first one allocates a new string and
the second one just points us to the internal configset storage. But
in fact they both allocate a new copy; the second one exists only to
avoid having to cast when using it with a const global which we never
intend to free.

The documentation for the function explains that clearly, but it seems
I'm not alone in being surprised by this. Of 17 calls to the function,
13 of them leak the resulting value.

We could obviously fix these by adding the appropriate free(). But it
would be simpler still if we actually had a non-allocating way to get
the string. There's git_config_get_value() but that doesn't quite do
what we want. If the config key is present but is a boolean with no
value (e.g., "[foo]bar" in the file), then we'll get NULL (whereas the
string versions will print an error and die).

So let's introduce a new variant, git_config_get_string_tmp(), that
behaves as these callers expect. We need a new name because we have new
semantics but the same function signature (so even if we converted the
four remaining callers, topics in flight might be surprised). The "tmp"
is because this value should only be held onto for a short time. In
practice it's rare for us to clear and refresh the configset,
invalidating the pointer, but hopefully the "tmp" makes callers think
about the lifetime. In each of the converted cases here the value only
needs to last within the local function or its immediate caller.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-14 10:52:04 -07:00
Jeff King d70a9eb611 strvec: rename struct fields
The "argc" and "argv" names made sense when the struct was argv_array,
but now they're just confusing. Let's rename them to "nr" (which we use
for counts elsewhere) and "v" (which is rather terse, but reads well
when combined with typical variable names like "args.v").

Note that we have to update all of the callers immediately. Playing
tricks with the preprocessor is hard here, because we wouldn't want to
rewrite unrelated tokens.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-30 19:18:06 -07:00
Jeff King f6d8942b1f strvec: fix indentation in renamed calls
Code which split an argv_array call across multiple lines, like:

  argv_array_pushl(&args, "one argument",
                   "another argument", "and more",
		   NULL);

was recently mechanically renamed to use strvec, which results in
mis-matched indentation like:

  strvec_pushl(&args, "one argument",
                   "another argument", "and more",
		   NULL);

Let's fix these up to align the arguments with the opening paren. I did
this manually by sifting through the results of:

  git jump grep 'strvec_.*,$'

and liberally applying my editor's auto-format. Most of the changes are
of the form shown above, though I also normalized a few that had
originally used a single-tab indentation (rather than our usual style of
aligning with the open paren). I also rewrapped a couple of obvious
cases (e.g., where previously too-long lines became short enough to fit
on one), but I wasn't aggressive about it. In cases broken to three or
more lines, the grouping of arguments is sometimes meaningful, and it
wasn't worth my time or reviewer time to ponder each case individually.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:18 -07:00
Jeff King 22f9b7f3f5 strvec: convert builtin/ callers away from argv_array name
We eventually want to drop the argv_array name and just use strvec
consistently. There's no particular reason we have to do it all at once,
or care about interactions between converted and unconverted bits.
Because of our preprocessor compat layer, the names are interchangeable
to the compiler (so even a definition and declaration using different
names is OK).

This patch converts all of the files in builtin/ to keep the diff to a
manageable size.

The conversion was done purely mechanically with:

  git ls-files '*.c' '*.h' |
  xargs perl -i -pe '
    s/ARGV_ARRAY/STRVEC/g;
    s/argv_array/strvec/g;
  '

and then selectively staging files with "git add builtin/". We'll deal
with any indentation/style fallouts separately.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:18 -07:00
Jeff King dbbcd44fb4 strvec: rename files from argv-array to strvec
This requires updating #include lines across the code-base, but that's
all fairly mechanical, and was done with:

  git ls-files '*.c' '*.h' |
  xargs perl -i -pe 's/argv-array.h/strvec.h/'

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:17 -07:00
Junio C Hamano 1033b98291 Merge branch 'xl/upgrade-repo-format'
Allow runtime upgrade of the repository format version, which needs
to be done carefully.

There is a rather unpleasant backward compatibility worry with the
last step of this series, but it is the right thing to do in the
longer term.

* xl/upgrade-repo-format:
  check_repository_format_gently(): refuse extensions for old repositories
  sparse-checkout: upgrade repository to version 1 when enabling extension
  fetch: allow adding a filter after initial clone
  repository: add a helper function to perform repository format upgrade
2020-06-29 14:17:24 -07:00
Junio C Hamano 524caf8035 Merge branch 'js/reflog-anonymize-for-clone-and-fetch'
The reflog entries for "git clone" and "git fetch" did not
anonymize the URL they operated on.

* js/reflog-anonymize-for-clone-and-fetch:
  clone/fetch: anonymize URLs in the reflog
2020-06-17 21:54:01 -07:00
Xin Li 01bbbbd9da fetch: allow adding a filter after initial clone
Retroactively adding a filter can be useful for existing shallow clones as
they allow users to see earlier change histories without downloading all
git objects in a regular --unshallow fetch.

Without this patch, users can make a clone partial by editing the
repository configuration to convert the remote into a promisor, like:

  git config core.repositoryFormatVersion 1
  git config extensions.partialClone origin
  git fetch --unshallow --filter=blob:none origin

Since the hard part of making this work is already in place and such
edits can be error-prone, teach Git to perform the required configuration
change automatically instead.

Note that this change does not modify the existing git behavior which
recognizes setting extensions.partialClone without changing
repositoryFormatVersion.

Signed-off-by: Xin Li <delphij@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-05 10:13:30 -07:00
Johannes Schindelin 46da295a77 clone/fetch: anonymize URLs in the reflog
Even if we strongly discourage putting credentials into the URLs passed
via the command-line, there _is_ support for that, and users _do_ do
that.

Let's scrub them before writing them to the reflog.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-04 13:20:21 -07:00
Junio C Hamano 3af459e48d Merge branch 'jc/auto-gc-quiet'
Teach "am", "commit", "merge" and "rebase", when they are run with
the "--quiet" option, to pass "--quiet" down to "gc --auto".

* jc/auto-gc-quiet:
  auto-gc: pass --quiet down from am, commit, merge and rebase
  auto-gc: extract a reusable helper from "git fetch"
2020-05-13 12:19:19 -07:00
Junio C Hamano 896833b268 Merge branch 'tb/shallow-cleanup'
Code cleanup.

* tb/shallow-cleanup:
  shallow: use struct 'shallow_lock' for additional safety
  shallow.h: document '{commit,rollback}_shallow_file'
  shallow: extract a header file for shallow-related functions
  commit: make 'commit_graft_pos' non-static
2020-05-13 12:19:18 -07:00
Junio C Hamano 850b6edefa auto-gc: extract a reusable helper from "git fetch"
Back in 1991006c (fetch: convert argv_gc_auto to struct argv_array,
2014-08-16), we taught "git fetch --quiet" to pass the "--quiet"
option down to "gc --auto".  This issue, however, is not limited to
"fetch":

    $ git grep -e 'gc.*--auto' \*.c

finds hits in "am", "commit", "merge", and "rebase" and these
commands do not pass "--quiet" down to "gc --auto" when they
themselves are told to be quiet.

As a preparatory step, let's introduce a helper function
run_auto_gc(), that the caller can pass a boolean "quiet",
and redo the fix to "git fetch" using the helper.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-07 12:24:33 -07:00
Taylor Blau 120ad2b0f1 shallow: extract a header file for shallow-related functions
There are many functions in commit.h that are more related to shallow
repositories than they are to any sort of generic commit machinery.
Likely this began when there were only a few shallow-related functions,
and commit.h seemed a reasonable enough place to put them.

But, now there are a good number of shallow-related functions, and
placing them all in 'commit.h' doesn't make sense.

This patch extracts a 'shallow.h', which takes all of the declarations
from 'commit.h' for functions which already exist in 'shallow.c'. We
will bring the remaining shallow-related functions defined in 'commit.c'
in a subsequent patch.

For now, move only the ones that already are implemented in 'shallow.c',
and update the necessary includes.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-30 14:19:13 -07:00
Denton Liu 203c85339f Use OPT_CALLBACK and OPT_CALLBACK_F
In the codebase, there are many options which use OPTION_CALLBACK in a
plain ol' struct definition. However, we have the OPT_CALLBACK and
OPT_CALLBACK_F macros which are meant to abstract these plain struct
definitions away. These macros are useful as they semantically signal to
developers that these are just normal callback option with nothing fancy
happening.

Replace plain struct definitions of OPTION_CALLBACK with OPT_CALLBACK or
OPT_CALLBACK_F where applicable. The heavy lifting was done using the
following (disgusting) shell script:

	#!/bin/sh

	do_replacement () {
		tr '\n' '\r' |
			sed -e 's/{\s*OPTION_CALLBACK,\s*\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\s*0,\(\s*[^[:space:]}]*\)\s*}/OPT_CALLBACK(\1,\2,\3,\4,\5,\6)/g' |
			sed -e 's/{\s*OPTION_CALLBACK,\s*\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\(\s*[^[:space:]}]*\)\s*}/OPT_CALLBACK_F(\1,\2,\3,\4,\5,\6,\7)/g' |
			tr '\r' '\n'
	}

	for f in $(git ls-files \*.c)
	do
		do_replacement <"$f" >"$f.tmp"
		mv "$f.tmp" "$f"
	done

The result was manually inspected and then reformatted to match the
style of the surrounding code. Finally, using
`git grep OPTION_CALLBACK \*.c`, leftover results which were not handled
by the script were manually transformed.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-28 10:47:10 -07:00
Junio C Hamano 0c601052a5 Merge branch 'jt/connectivity-check-optim-in-partial-clone'
Simplify the commit ancestry connectedness check in a partial clone
repository in which "promised" objects are assumed to be obtainable
lazily on-demand from promisor remote repositories.

* jt/connectivity-check-optim-in-partial-clone:
  connected: always use partial clone optimization
2020-04-22 13:42:43 -07:00
Jonathan Tan 2b98478c6f connected: always use partial clone optimization
With 50033772d5 ("connected: verify promisor-ness of partial clone",
2020-01-30), the fast path (checking promisor packs) in
check_connected() now passes a subset of the slow path (rev-list) - if
all objects to be checked are found in promisor packs, both the fast
path and the slow path will pass; otherwise, the fast path will
definitely not pass. This means that we can always attempt the fast path
whenever we need to do the slow path.

The fast path is currently guarded by a flag; therefore, remove that
flag. Also, make the fast path fallback to the slow path - if the fast
path fails, the failing OID and all remaining OIDs will be passed to
rev-list.

The main user-visible benefit is the performance of fetch from a partial
clone - specifically, the speedup of the connectivity check done before
the fetch. In particular, a no-op fetch into a partial clone on my
computer was sped up from 7 seconds to 0.01 seconds. This is a
complement to the work in 2df1aa239c ("fetch: forgo full
connectivity check if --filter", 2020-01-30), which is the child of the
aforementioned 50033772d5. In that commit, the connectivity check
*after* the fetch was sped up.

The addition of the fast path might cause performance reductions in
these cases:

 - If a partial clone or a fetch into a partial clone fails, Git will
   fruitlessly run rev-list (it is expected that everything fetched
   would go into promisor packs, so if that didn't happen, it is most
   likely that rev-list will fail too).

 - Any connectivity checks done by receive-pack, in the (in my opinion,
   unlikely) event that a partial clone serves receive-pack.

I think that these cases are rare enough, and the performance reduction
in this case minor enough (additional object DB access), that the
benefit of avoiding a flag outweighs these.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Reviewed-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-29 10:37:44 -07:00
Junio C Hamano 444cff61b4 Merge branch 'ds/partial-clone-fixes'
Fix for a bug revealed by a recent change to make the protocol v2
the default.

* ds/partial-clone-fixes:
  partial-clone: avoid fetching when looking for objects
  partial-clone: demonstrate bugs in partial fetch
2020-03-02 15:07:19 -08:00
Derrick Stolee 3e96c66805 partial-clone: avoid fetching when looking for objects
When using partial clone, find_non_local_tags() in builtin/fetch.c
checks each remote tag to see if its object also exists locally. There
is no expectation that the object exist locally, but this function
nevertheless triggers a lazy fetch if the object does not exist. This
can be extremely expensive when asking for a commit, as we are
completely removed from the context of the non-existent object and
thus supply no "haves" in the request.

6462d5eb9a (fetch: remove fetch_if_missing=0, 2019-11-05) removed a
global variable that prevented these fetches in favor of a bitflag.
However, some object existence checks were not updated to use this flag.

Update find_non_local_tags() to use OBJECT_INFO_SKIP_FETCH_OBJECT in
addition to OBJECT_INFO_QUICK. The _QUICK option only prevents
repreparing the pack-file structures. We need to be extremely careful
about supplying _SKIP_FETCH_OBJECT when we expect an object to not exist
due to updated refs.

This resolves a broken test in t5616-partial-clone.sh.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-22 09:23:08 -08:00
Junio C Hamano 53c3be2c29 Merge branch 'tb/commit-graph-object-dir'
The code to compute the commit-graph has been taught to use a more
robust way to tell if two object directories refer to the same
thing.

* tb/commit-graph-object-dir:
  commit-graph.h: use odb in 'load_commit_graph_one_fd_st'
  commit-graph.c: remove path normalization, comparison
  commit-graph.h: store object directory in 'struct commit_graph'
  commit-graph.h: store an odb in 'struct write_commit_graph_context'
  t5318: don't pass non-object directory to '--object-dir'
2020-02-14 12:54:24 -08:00
Taylor Blau 0bd52e27e3 commit-graph.h: store an odb in 'struct write_commit_graph_context'
There are lots of places in 'commit-graph.h' where a function either has
(or almost has) a full 'struct object_directory *', accesses '->path',
and then throws away the rest of the struct.

This can cause headaches when comparing the locations of object
directories across alternates (e.g., in the case of deciding if two
commit-graph layers can be merged). These paths are normalized with
'normalize_path_copy()' which mitigates some comparison issues, but not
all [1].

Replace usage of 'char *object_dir' with 'odb->path' by storing a
'struct object_directory *' in the 'write_commit_graph_context'
structure. This is an intermediate step towards getting rid of all path
normalization in 'commit-graph.c'.

Resolving a user-provided '--object-dir' argument now requires that we
compare it to the known alternates for equality.  Prior to this patch,
an unknown '--object-dir' argument would silently exit with status zero.

This can clearly lead to unintended behavior, such as verifying
commit-graphs that aren't in a repository's own object store (or one of
its alternates), or causing a typo to mask a legitimate commit-graph
verification failure. Make this error non-silent by 'die()'-ing when the
given '--object-dir' does not match any known alternate object store.

[1]: In my testing, for example, I can get one side of the commit-graph
code to fill object_dir with "./objects" and the other with just
"objects".

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04 11:36:37 -08:00
Jonathan Tan 2df1aa239c fetch: forgo full connectivity check if --filter
If a filter is specified, we do not need a full connectivity check on
the contents of the packfile we just fetched; we only need to check that
the objects referenced are promisor objects.

This significantly speeds up fetches into repositories that have many
promisor objects, because during the connectivity check, all promisor
objects are enumerated (to mark them UNINTERESTING), and that takes a
significant amount of time.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-30 10:55:47 -08:00