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2017-10-30files-backend: don't rewrite the `packed-refs` file unnecessarilyLibravatar Michael Haggerty4-3/+122
Even when we are deleting references, we needn't overwrite the `packed-refs` file if the references that we are deleting only exist as loose references. Implement this optimization as follows: * Add a function `is_packed_transaction_needed()`, which checks whether a given packed-refs transaction actually needs to be carried out (i.e., it returns false if the transaction obviously wouldn't have any effect). This function must be called while holding the `packed-refs` lock to avoid races. * Change `files_transaction_prepare()` to check whether the packed-refs transaction is actually needed. If not, squelch it, but continue holding the `packed-refs` lock until the end of the transaction to avoid races. This fixes a mild regression caused by dc39e09942 (files_ref_store: use a transaction to update packed refs, 2017-09-08). Before that commit, unnecessary rewrites of `packed-refs` were suppressed by `repack_without_refs()`. But the transaction-based writing introduced by that commit didn't perform that optimization. Note that the pre-dc39e09942 code still had to *read* the whole `packed-refs` file to determine that the rewrite could be skipped, so the performance for the cases that the write could be elided was `O(N)` in the number of packed references both before and after dc39e09942. But after that commit the constant factor increased. This commit reimplements the optimization of eliding unnecessary `packed-refs` rewrites. That, plus the fact that since cfa2e29c34 (packed_ref_store: get rid of the `ref_cache` entirely, 2017-03-17) we don't necessarily have to read the whole `packed-refs` file at all, means that deletes of one or a few loose references can now be done with `O(n lg N)` effort, where `n` is the number of loose references being deleted and `N` is the total number of packed references. This commit fixes two tests in t1409. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-27t1409: check that `packed-refs` is not rewritten unnecessarilyLibravatar Michael Haggerty1-0/+118
There is no need to rewrite the `packed-refs` file except for the case that we are deleting a reference that has a packed version. Verify that `packed-refs` is not rewritten when it shouldn't be. In fact, two of these tests fail: * A new (empty) `packed-refs` file is created when deleting any loose reference and no `packed-refs` file previously existed. * The `packed-refs` file is rewritten unnecessarily when deleting a loose reference that has no packed counterpart. Both problems will be fixed in the next commit. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09files_transaction_finish(): delete reflogs before referencesLibravatar Michael Haggerty1-14/+21
If the deletion steps unexpectedly fail, it is less bad to leave a reference without its reflog than it is to leave a reflog without its reference, since the latter is an invalid repository state. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09packed-backend: rip out some now-unused codeLibravatar Michael Haggerty2-201/+0
Now the outside world interacts with the packed ref store only via the generic refs API plus a few lock-related functions. This allows us to delete some functions that are no longer used, thereby completing the encapsulation of the packed ref store. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09files_ref_store: use a transaction to update packed refsLibravatar Michael Haggerty2-33/+103
When processing a `files_ref_store` transaction, it is sometimes necessary to delete some references from the "packed-refs" file. Do that using a reference transaction conducted against the `packed_ref_store`. This change further decouples `files_ref_store` from `packed_ref_store`. It also fixes multiple problems, including the two revealed by test cases added in the previous commit. First, the old code didn't obtain the `packed-refs` lock until `files_transaction_finish()`. This means that a failure to acquire the `packed-refs` lock (e.g., due to contention with another process) wasn't detected until it was too late (problems like this are supposed to be detected in the "prepare" phase). The new code acquires the `packed-refs` lock in `files_transaction_prepare()`, the same stage of the processing when the loose reference locks are being acquired, removing another reason why the "prepare" phase might succeed and the "finish" phase might nevertheless fail. Second, the old code deleted the loose version of a reference before deleting any packed version of the same reference. This left a moment when another process might think that the packed version of the reference is current, which is incorrect. (Even worse, the packed version of the reference can be arbitrarily old, and might even point at an object that has since been garbage-collected.) Third, if a reference deletion fails to acquire the `packed-refs` lock altogether, then the old code might leave the repository in the incorrect state (possibly corrupt) described in the previous paragraph. Now we activate the new "packed-refs" file (sans any references that are being deleted) *before* deleting the corresponding loose references. But we hold the "packed-refs" lock until after the loose references have been finalized, thus preventing a simultaneous "pack-refs" process from packing the loose version of the reference in the time gap, which would otherwise defeat our attempt to delete it. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09t1404: demonstrate two problems with reference transactionsLibravatar Michael Haggerty1-0/+73
Currently, a loose reference is deleted even before locking the `packed-refs` file, let alone deleting any packed version of the reference. This leads to two problems, demonstrated by two new tests: * While a reference is being deleted, other processes might see the old, packed value of the reference for a moment before the packed version is deleted. Normally this would be hard to observe, but we can prolong the window by locking the `packed-refs` file externally before running `update-ref`, then unlocking it before `update-ref`'s attempt to acquire the lock times out. * If the `packed-refs` file is locked so long that `update-ref` fails to lock it, then the reference can be left permanently in the incorrect state described in the previous point. In a moment, both problems will be fixed. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09files_initial_transaction_commit(): use a transaction for packed refsLibravatar Michael Haggerty1-10/+19
Use a `packed_ref_store` transaction in the implementation of `files_initial_transaction_commit()` rather than using internal features of the packed ref store. This further decouples `files_ref_store` from `packed_ref_store`. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09prune_refs(): also free the linked listLibravatar Michael Haggerty1-4/+10
At least since v1.7, the elements of the `refs_to_prune` linked list have been leaked. Fix the leak by teaching `prune_refs()` to free the list elements as it processes them. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09files_pack_refs(): use a reference transaction to write packed refsLibravatar Michael Haggerty1-7/+17
Now that the packed reference store supports transactions, we can use a transaction to write the packed versions of references that we want to pack. This decreases the coupling between `files_ref_store` and `packed_ref_store`. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09packed_delete_refs(): implement methodLibravatar Michael Haggerty2-2/+45
Implement `packed_delete_refs()` using a reference transaction. This means that `files_delete_refs()` can use `refs_delete_refs()` instead of `repack_without_refs()` to delete any packed references, decreasing the coupling between the classes. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09packed_ref_store: implement reference transactionsLibravatar Michael Haggerty2-3/+319
Implement the methods needed to support reference transactions for the packed-refs backend. The new methods are not yet used. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09struct ref_transaction: add a place for backends to store dataLibravatar Michael Haggerty1-0/+1
`packed_ref_store` is going to want to store some transaction-wide data, so make a place for it. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09packed-backend: don't adjust the reference count on lock/unlockLibravatar Michael Haggerty1-5/+5
The old code incremented the packed ref cache reference count when acquiring the packed-refs lock, and decremented the count when releasing the lock. This is unnecessary because: * Another process cannot change the packed-refs file because it is locked. * When we ourselves change the packed-refs file, we do so by first modifying the packed ref-cache, and then writing the data from the ref-cache to disk. So the packed ref-cache remains fresh because any changes that we plan to make to the file are made in the cache first anyway. So there is no reason for the cache to become stale. Moreover, the extra reference count causes a problem if we intentionally clear the packed refs cache, as we sometimes need to do if we change the cache in anticipation of writing a change to disk, but then the write to disk fails. In that case, `packed_refs_unlock()` would have no easy way to find the cache whose reference count it needs to decrement. This whole issue will soon become moot due to upcoming changes that avoid changing the in-memory cache as part of updating the packed-refs on disk, but this change makes that transition easier. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-26The fifth batch post 2.14Libravatar Junio C Hamano1-1/+49
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-26Merge branch 'mg/killed-merge'Libravatar Junio C Hamano3-4/+31
Killing "git merge --edit" before the editor returns control left the repository in a state with MERGE_MSG but without MERGE_HEAD, which incorrectly tells the subsequent "git commit" that there was a squash merge in progress. This has been fixed. * mg/killed-merge: merge: save merge state earlier merge: split write_merge_state in two merge: clarify call chain Documentation/git-merge: explain --continue
2017-08-26Merge branch 'jt/packmigrate'Libravatar Junio C Hamano37-2014/+2081
Code movement to make it easier to hack later. * jt/packmigrate: (23 commits) pack: move for_each_packed_object() pack: move has_pack_index() pack: move has_sha1_pack() pack: move find_pack_entry() and make it global pack: move find_sha1_pack() pack: move find_pack_entry_one(), is_pack_valid() pack: move check_pack_index_ptr(), nth_packed_object_offset() pack: move nth_packed_object_{sha1,oid} pack: move clear_delta_base_cache(), packed_object_info(), unpack_entry() pack: move unpack_object_header() pack: move get_size_from_delta() pack: move unpack_object_header_buffer() pack: move {,re}prepare_packed_git and approximate_object_count pack: move install_packed_git() pack: move add_packed_git() pack: move unuse_pack() pack: move use_pack() pack: move pack-closing functions pack: move release_pack_memory() pack: move open_pack_index(), parse_pack_index() ...
2017-08-26Merge branch 'mh/ref-lock-entry'Libravatar Junio C Hamano4-5/+39
The code to acquire a lock on a reference (e.g. while accepting a push from a client) used to immediately fail when the reference is already locked---now it waits for a very short while and retries, which can make it succeed if the lock holder was holding it during a read-only operation. * mh/ref-lock-entry: refs: retry acquiring reference locks for 100ms
2017-08-26Merge branch 'jt/doc-pack-objects-fix'Libravatar Junio C Hamano1-6/+11
Doc updates. * jt/doc-pack-objects-fix: Doc: clarify that pack-objects makes packs, plural
2017-08-26Merge branch 'jc/cutoff-config'Libravatar Junio C Hamano5-31/+79
"[gc] rerereResolved = 5.days" used to be invalid, as the variable is defined to take an integer counting the number of days. It now is allowed. * jc/cutoff-config: rerere: allow approxidate in gc.rerereResolved/gc.rerereUnresolved rerere: represent time duration in timestamp_t internally t4200: parameterize "rerere gc" custom expiry test t4200: gather "rerere gc" together t4200: make "rerere gc" test more robust t4200: give us a clean slate after "rerere gc" tests
2017-08-26Merge branch 'kw/write-index-reduce-alloc'Libravatar Junio C Hamano4-28/+87
We used to spend more than necessary cycles allocating and freeing piece of memory while writing each index entry out. This has been optimized. * kw/write-index-reduce-alloc: read-cache: avoid allocating every ondisk entry when writing read-cache: fix memory leak in do_write_index perf: add test for writing the index
2017-08-26Merge branch 'bw/submodule-config-cleanup'Libravatar Junio C Hamano25-373/+192
Code clean-up to avoid mixing values read from the .gitmodules file and values read from the .git/config file. * bw/submodule-config-cleanup: submodule: remove gitmodules_config unpack-trees: improve loading of .gitmodules submodule-config: lazy-load a repository's .gitmodules file submodule-config: move submodule-config functions to submodule-config.c submodule-config: remove support for overlaying repository config diff: stop allowing diff to have submodules configured in .git/config submodule: remove submodule_config callback routine unpack-trees: don't respect submodule.update submodule: don't rely on overlayed config when setting diffopts fetch: don't overlay config with submodule-config submodule--helper: don't overlay config in update-clone submodule--helper: don't overlay config in remote_submodule_branch add, reset: ensure submodules can be added or reset submodule: don't use submodule_from_name t7411: check configuration parsing errors
2017-08-26Merge branch 'js/gitweb-raw-blob-link-in-history'Libravatar Junio C Hamano1-0/+3
"gitweb" shows a link to visit the 'raw' contents of blbos in the history overview page. * js/gitweb-raw-blob-link-in-history: gitweb: add 'raw' blob_plain link in history overview
2017-08-26Merge branch 'po/object-id'Libravatar Junio C Hamano9-34/+34
* po/object-id: sha1_file: convert index_stream to struct object_id sha1_file: convert hash_sha1_file_literally to struct object_id sha1_file: convert index_fd to struct object_id sha1_file: convert index_path to struct object_id read-cache: convert to struct object_id builtin/hash-object: convert to struct object_id
2017-08-26Merge branch 'jn/vcs-svn-cleanup'Libravatar Junio C Hamano6-86/+56
Code clean-up. * jn/vcs-svn-cleanup: vcs-svn: move remaining repo_tree functions to fast_export.h vcs-svn: remove repo_delete wrapper function vcs-svn: remove custom mode constants vcs-svn: remove more unused prototypes and declarations
2017-08-26Merge branch 'bc/vcs-svn-cleanup'Libravatar Junio C Hamano3-17/+10
Code clean-up. * bc/vcs-svn-cleanup: vcs-svn: rename repo functions to "svn_repo" vcs-svn: remove unused prototypes
2017-08-26Merge branch 'tb/apply-with-crlf'Libravatar Junio C Hamano4-16/+71
"git apply" that is used as a better "patch -p1" failed to apply a taken from a file with CRLF line endings to a file with CRLF line endings. The root cause was because it misused convert_to_git() that tried to do "safe-crlf" processing by looking at the index entry at the same path, which is a nonsense---in that mode, "apply" is not working on the data in (or derived from) the index at all. This has been fixed. * tb/apply-with-crlf: apply: file commited with CRLF should roundtrip diff and apply convert: add SAFE_CRLF_KEEP_CRLF
2017-08-26Merge branch 'jt/stash-tests'Libravatar Junio C Hamano1-0/+34
Test update to improve coverage for "git stash" operations. * jt/stash-tests: stash: add a test for stashing in a detached state stash: add a test for when apply fails during stash branch stash: add a test for stash create with no files
2017-08-26Merge branch 'jk/trailers-parse'Libravatar Junio C Hamano8-52/+314
"git interpret-trailers" has been taught a "--parse" and a few other options to make it easier for scripts to grab existing trailer lines from a commit log message. * jk/trailers-parse: doc/interpret-trailers: fix "the this" typo pretty: support normalization options for %(trailers) t4205: refactor %(trailers) tests pretty: move trailer formatting to trailer.c interpret-trailers: add --parse convenience option interpret-trailers: add an option to unfold values interpret-trailers: add an option to show only existing trailers interpret-trailers: add an option to show only the trailers trailer: put process_trailers() options into a struct
2017-08-26Merge branch 'pb/trailers-from-command-line'Libravatar Junio C Hamano5-53/+274
"git interpret-trailers" learned to take the trailer specifications from the command line that overrides the configured values. * pb/trailers-from-command-line: interpret-trailers: fix documentation typo interpret-trailers: add options for actions trailers: introduce struct new_trailer_item trailers: export action enums and corresponding lookup functions
2017-08-26Merge branch 'jt/diff-color-move-fix'Libravatar Junio C Hamano4-82/+236
A handful of bugfixes and an improvement to "diff --color-moved". * jt/diff-color-move-fix: diff: define block by number of alphanumeric chars diff: respect MIN_BLOCK_LENGTH for last block diff: avoid redundantly clearing a flag
2017-08-26Merge branch 'sb/diff-color-move'Libravatar Junio C Hamano9-316/+1618
"git diff" has been taught to optionally paint new lines that are the same as deleted lines elsewhere differently from genuinely new lines. * sb/diff-color-move: (25 commits) diff: document the new --color-moved setting diff.c: add dimming to moved line detection diff.c: color moved lines differently, plain mode diff.c: color moved lines differently diff.c: buffer all output if asked to diff.c: emit_diff_symbol learns about DIFF_SYMBOL_SUMMARY diff.c: emit_diff_symbol learns about DIFF_SYMBOL_STAT_SEP diff.c: convert word diffing to use emit_diff_symbol diff.c: convert show_stats to use emit_diff_symbol diff.c: convert emit_binary_diff_body to use emit_diff_symbol submodule.c: migrate diff output to use emit_diff_symbol diff.c: emit_diff_symbol learns DIFF_SYMBOL_REWRITE_DIFF diff.c: emit_diff_symbol learns about DIFF_SYMBOL_BINARY_FILES diff.c: emit_diff_symbol learns DIFF_SYMBOL_HEADER diff.c: emit_diff_symbol learns DIFF_SYMBOL_FILEPAIR_{PLUS, MINUS} diff.c: emit_diff_symbol learns DIFF_SYMBOL_CONTEXT_INCOMPLETE diff.c: emit_diff_symbol learns DIFF_SYMBOL_WORDS[_PORCELAIN] diff.c: migrate emit_line_checked to use emit_diff_symbol diff.c: emit_diff_symbol learns DIFF_SYMBOL_NO_LF_EOF diff.c: emit_diff_symbol learns DIFF_SYMBOL_CONTEXT_FRAGINFO ...
2017-08-24The fourth batch post 2.14Libravatar Junio C Hamano1-21/+19
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-24Merge branch 'jk/doc-the-this'Libravatar Junio C Hamano1-2/+2
Doc clean-up. * jk/doc-the-this: doc: fix typo in sendemail.identity
2017-08-24Merge branch 'rs/commit-h-single-parent-cleanup'Libravatar Junio C Hamano1-5/+0
Code clean-up. * rs/commit-h-single-parent-cleanup: commit: remove unused inline function single_parent()
2017-08-24Merge branch 'jc/simplify-progress'Libravatar Junio C Hamano10-19/+20
The API to start showing progress meter after a short delay has been simplified. * jc/simplify-progress: progress: simplify "delayed" progress API
2017-08-24Merge branch 'tc/curl-with-backports'Libravatar Junio C Hamano1-4/+6
Updates to the HTTP layer we made recently unconditionally used features of libCurl without checking the existence of them, causing compilation errors, which has been fixed. Also migrate the code to check feature macros, not version numbers, to cope better with libCurl that vendor ships with backported features. * tc/curl-with-backports: http: use a feature check to enable GSSAPI delegation control http: fix handling of missing CURLPROTO_*
2017-08-24Merge branch 'cc/subprocess-handshake-missing-capabilities'Libravatar Junio C Hamano1-2/+2
When handshake with a subprocess filter notices that the process asked for an unknown capability, Git did not report what program the offending subprocess was running. This has been corrected. * cc/subprocess-handshake-missing-capabilities: sub-process: print the cmd when a capability is unsupported
2017-08-24Merge branch 'rs/object-id'Libravatar Junio C Hamano8-23/+23
Conversion from uchar[20] to struct object_id continues. * rs/object-id: tree-walk: convert fill_tree_descriptor() to object_id
2017-08-24Merge branch 'lg/merge-signoff'Libravatar Junio C Hamano3-0/+81
"git merge" learned a "--signoff" option to add the Signed-off-by: trailer with the committer's name. * lg/merge-signoff: merge: add a --signoff flag
2017-08-23pack: move for_each_packed_object()Libravatar Jonathan Tan6-46/+54
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23pack: move has_pack_index()Libravatar Jonathan Tan4-10/+10
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23pack: move has_sha1_pack()Libravatar Jonathan Tan7-8/+11
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23pack: move find_pack_entry() and make it globalLibravatar Jonathan Tan3-53/+55
This function needs to be global as it is used by sha1_file.c and will be used by packfile.c. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23pack: move find_sha1_pack()Libravatar Jonathan Tan6-16/+18
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23pack: move find_pack_entry_one(), is_pack_valid()Libravatar Jonathan Tan4-84/+82
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23pack: move check_pack_index_ptr(), nth_packed_object_offset()Libravatar Jonathan Tan4-49/+49
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23pack: move nth_packed_object_{sha1,oid}Libravatar Jonathan Tan4-46/+46
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23pack: move clear_delta_base_cache(), packed_object_info(), unpack_entry()Libravatar Jonathan Tan4-670/+685
Both sha1_file.c and packfile.c now need read_object(), so a copy of read_object() was created in packfile.c. This patch makes both mark_bad_packed_object() and has_packed_and_bad() global. Unlike most of the other patches in this series, these 2 functions need to remain global. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23pack: move unpack_object_header()Libravatar Jonathan Tan4-27/+27
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23pack: move get_size_from_delta()Libravatar Jonathan Tan4-40/+41
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>