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2022-03-28fetch-negotiator: add specific noop initializerRobert Coup
Add a specific initializer for the noop fetch negotiator. This is introduced to support allowing partial clones to skip commit negotiation when performing a "refetch". Signed-off-by: Robert Coup <robert@coup.net.nz> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-02repo-settings: rename the traditional default fetch.negotiationAlgorithmElijah Newren
Give the traditional default fetch.negotiationAlgorithm the name 'consecutive'. Also allow a choice of 'default' to have Git decide between the choices (currently, picking 'skipping' if feature.experimental is true and 'consecutive' otherwise). Update the documentation accordingly. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-22repo-settings.c: simplify the setupÆvar Arnfjörð Bjarmason
Simplify the setup code in repo-settings.c in various ways, making the code shorter, easier to read, and requiring fewer hacks to do the same thing as it did before: Since 7211b9e7534 (repo-settings: consolidate some config settings, 2019-08-13) we have memset() the whole "settings" structure to -1 in prepare_repo_settings(), and subsequently relied on the -1 value. Most of the fields did not need to be initialized to -1, and because we were doing that we had the enum labels "UNTRACKED_CACHE_UNSET" and "FETCH_NEGOTIATION_UNSET" purely to reflect the resulting state created this memset() in prepare_repo_settings(). No other code used or relied on them, more on that below. For the rest most of the subsequent "are we -1, then read xyz" can simply be removed by re-arranging what we read first. E.g. when setting the "index.version" setting we should have first read "feature.experimental", so that it (and "feature.manyfiles") can provide a default for our "index.version". Instead the code setting it, added when "feature.manyFiles"[1] was created, was using the UPDATE_DEFAULT_BOOL() macro added in an earlier commit[2]. That macro is now gone, since it was only needed for this pattern of reading things in the wrong order. This also fixes an (admittedly obscure) logic error where we'd conflate an explicit "-1" value in the config with our own earlier memset() -1. We can also remove the UPDATE_DEFAULT_BOOL() wrapper added in [3]. Using it is redundant to simply using the return value from repo_config_get_bool(), which is non-zero if the provided key exists in the config. Details on edge cases relating to the memset() to -1, continued from "more on that below" above: * UNTRACKED_CACHE_KEEP: In [4] the "unset" and "keep" handling for core.untrackedCache was consolidated. But it while we understand the "keep" value, we don't handle it differently than the case of any other unknown value. So let's retain UNTRACKED_CACHE_KEEP and remove the UNTRACKED_CACHE_UNSET setting (which was always implicitly UNTRACKED_CACHE_KEEP before). We don't need to inform any code after prepare_repo_settings() that the setting was "unset", as far as anyone else is concerned it's core.untrackedCache=keep. if "core.untrackedcache" isn't present in the config. * FETCH_NEGOTIATION_UNSET & FETCH_NEGOTIATION_NONE: Since these two two enum fields added in [5] don't rely on the memzero() setting them to "-1" anymore we don't have to provide them with explicit values. 1. c6cc4c5afd2 (repo-settings: create feature.manyFiles setting, 2019-08-13) 2. 31b1de6a09b (commit-graph: turn on commit-graph by default, 2019-08-13) 3. 31b1de6a09b (commit-graph: turn on commit-graph by default, 2019-08-13) 4. ad0fb659993 (repo-settings: parse core.untrackedCache, 2019-08-13) 5. aaf633c2ad1 (repo-settings: create feature.experimental setting, 2019-08-13) Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-22read-cache & fetch-negotiator: check "enum" values in switch()Ævar Arnfjörð Bjarmason
Change tweak_untracked_cache() in "read-cache.c" to use a switch() to have the compiler assert that we checked all possible values in the "enum untracked_cache_setting" type, and likewise remove the "default" case in fetch_negotiator_init() in favor of checking for "FETCH_NEGOTIATION_UNSET" and "FETCH_NEGOTIATION_NONE". As will be discussed in a subsequent we'll only ever have either of these set to FETCH_NEGOTIATION_NONE, FETCH_NEGOTIATION_UNSET and UNTRACKED_CACHE_UNSET within the prepare_repo_settings() function itself. In preparation for fixing that code let's add a BUG() here to mark this as unreachable code. See ad0fb659993 (repo-settings: parse core.untrackedCache, 2019-08-13) for when the "unset" and "keep" handling for core.untrackedCache was consolidated, and aaf633c2ad1 (repo-settings: create feature.experimental setting, 2019-08-13) for the addition of the "default" pattern in "fetch-negotiator.c". Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-18negotiator/noop: add noop fetch negotiatorJonathan Tan
Add a noop fetch negotiator. This is introduced to allow partial clones to skip the unneeded negotiation step when fetching missing objects using a "git fetch" subprocess. (The implementation of spawning a "git fetch" subprocess will be done in a subsequent patch.) But this can also be useful for end users, e.g. as a blunt fix for object corruption. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-13repo-settings: create feature.experimental settingDerrick Stolee
The 'feature.experimental' setting includes config options that are not committed to become defaults, but could use additional testing. Update the following config settings to take new defaults, and to use the repo_settings struct if not already using them: * 'pack.useSparse=true' * 'fetch.negotiationAlgorithm=skipping' In the case of fetch.negotiationAlgorithm, the existing logic would load the config option only when about to use the setting, so had a die() statement on an unknown string value. This is removed as now the config is parsed under prepare_repo_settings(). In general, this die() is probably misplaced and not valuable. A test was removed that checked this die() statement executed. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-01negotiator: unknown fetch.negotiationAlgorithm should error outÆvar Arnfjörð Bjarmason
Change the handling of fetch.negotiationAlgorithm=<str> to error out on unknown strings, i.e. everything except "default" or "skipping". This changes the behavior added in 42cc7485a2 ("negotiator/skipping: skip commits during fetch", 2018-07-16) which would ignore all unknown values and silently fall back to the "default" value. For a feature like this it's much better to produce an error than proceed. We don't want users to debug some amazingly slow fetch that should benefit from "skipping", only to find that they'd forgotten to deploy the new git version on that particular machine. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-16negotiator/skipping: skip commits during fetchJonathan Tan
Introduce a new negotiation algorithm used during fetch that skips commits in an effort to find common ancestors faster. The skips grow similarly to the Fibonacci sequence as the commit walk proceeds further away from the tips. The skips may cause unnecessary commits to be included in the packfile, but the negotiation step typically ends more quickly. Usage of this algorithm is guarded behind the configuration flag fetch.negotiationAlgorithm. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-15fetch-pack: introduce negotiator APIJonathan Tan
Introduce the new files fetch-negotiator.{h,c}, which contains an API behind which the details of negotiation are abstracted. Currently, only one algorithm is available: the existing one. This patch is written to be easily reviewed: static functions are moved verbatim from fetch-pack.c to negotiator/default.c, and it can be seen that the lines replaced by negotiator->X() calls are present in the X() functions respectively. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>