From patchwork Sat Apr 10 02:03:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philippe Blain via GitGitGadget X-Patchwork-Id: 12195301 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AE8FC433ED for ; Sat, 10 Apr 2021 02:04:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DA64E61178 for ; Sat, 10 Apr 2021 02:04:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233687AbhDJCEN (ORCPT ); Fri, 9 Apr 2021 22:04:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38402 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231737AbhDJCEL (ORCPT ); Fri, 9 Apr 2021 22:04:11 -0400 Received: from mail-wm1-x32a.google.com (mail-wm1-x32a.google.com [IPv6:2a00:1450:4864:20::32a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4ACBEC061763 for ; Fri, 9 Apr 2021 19:03:57 -0700 (PDT) Received: by mail-wm1-x32a.google.com with SMTP id 12so3777304wmf.5 for ; Fri, 09 Apr 2021 19:03:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=+ZbCteYk911AHUKcwxzUe7Bagc0zgojgJVYwQ6+RGQ0=; b=t+r++CX/rtLjF1e5Y3sWLPoZZgP5rNZbEw7JBUNhhWWkvihSl17NE+Nn8STPEHIfxO AzhYilab5j7hCBmoHJaMS4/7ot07WaHQChNB6BxpYQcMzgU3WfktjSEaEN/hF9OG+YAz 065LQ9IFodieqn/Okx1ne7SfRJzaVbZYWu2N6lzqR7s5kC4i5pAgc7OVJv6G+rM88t5S 1ftG7L43yS0YkMYAGvqCofJnCWoXpD3fz6QwixyL15RAVcuEQFo5gNXlVA1XWcK2NSM0 5ehh4ZrTq0ZGetVIuxkayN0iymukz2Pq8ohLhxwxAeGcpospG3YRNS9egCDhlJePKrn1 GmBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=+ZbCteYk911AHUKcwxzUe7Bagc0zgojgJVYwQ6+RGQ0=; b=S5Y6c3u2z978V6FdX3GUhiZOvmnaNB836n6xEKs6ViCNxyIl8q0iVCEYmuF/szrLha A2qJpZ19/WNnotVif5Ew+AOruyYMBIB0XnAxN+vRO2kVW2WaJxR1nwfGovcuDnBbCJJQ cXTrdEk2TKTLexNYkVF0AUkmO8OCFrNHDO4NdZZRXBch7F3INjgNTl8+J5CauXS4SMGa jMEAz2XuJKlyjJtphhHDGnwVBQVySi9dFPRE6f8oqAZBcgl6Mk7+Jw9L0iH1G4L5Z3iy IDzUv3OXSNbKv1EA6AvfAxNQDB5cliqVgLDmO7/zKjylUhn/NuvT/l4wc3Jzo+yVHLum nswA== X-Gm-Message-State: AOAM530i3+wvAORk+TwYAMqmE0zu9LwXK3d+XSaoF0AcZINyTj3Njzny LIvC6gXtvTfOXx+PuBpFZ781OPpoc3o= X-Google-Smtp-Source: ABdhPJzkJ3vL2809DdfPlqlGjjPQ/szrX6wkzZP7BGyUjEqrm6B7sTxCdLX3oLTpXbM1YY3uFh/YIg== X-Received: by 2002:a1c:c341:: with SMTP id t62mr16191394wmf.27.1618020227173; Fri, 09 Apr 2021 19:03:47 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id d5sm8443326wrx.0.2021.04.09.19.03.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Apr 2021 19:03:46 -0700 (PDT) Message-Id: In-Reply-To: References: From: "Derrick Stolee via GitGitGadget" Date: Sat, 10 Apr 2021 02:03:42 +0000 Subject: [PATCH v3 0/3] Maintenance: adapt custom refspecs Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: tom.saeger@oracle.com, gitster@pobox.com, sunshine@sunshineco.com, Derrick Stolee , Josh Steadmon , Emily Shaffer , Derrick Stolee Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Tom Saeger rightly pointed out [1] that the prefetch task ignores custom refspecs. This can lead to downloading more data than requested, and it doesn't even help the future foreground fetches that use that custom refspec. [1] https://lore.kernel.org/git/20210401184914.qmr7jhjbhp2mt3h6@dhcp-10-154-148-175.vpn.oracle.com/ This series fixes this problem by carefully replacing the start of each refspec's destination with "refs/prefetch/". If the destination already starts with "refs/", then that is replaced. Otherwise "refs/prefetch/" is just prepended. This happens inside of git fetch when a --prefetch option is given. This allows us to maniuplate a struct refspec_item instead of a full refspec string. It also simplifies our logic in testing the prefetch task. Update in V3 ============ * The fix is almost completely rewritten as an update to 'git fetch'. See the new PATCH 2 for this update. * There was some discussion of rewriting test_subcommand, but that can be delayed until a proper solution is found to complications around softer matches. Updates in V2 ============= Thanks for the close eye on this series. I appreciate the recommendations, which I believe I have responded to them all: * Fixed typos. * Made refspec_item_format() re-entrant. Consumers must free the buffer. * Cleaned up style (quoting and tabbing). Thanks, -Stolee Derrick Stolee (3): maintenance: simplify prefetch logic fetch: add --prefetch option maintenance: use 'git fetch --prefetch' Documentation/fetch-options.txt | 5 +++ Documentation/git-maintenance.txt | 6 ++-- builtin/fetch.c | 56 +++++++++++++++++++++++++++++++ builtin/gc.c | 36 +++++--------------- t/t5582-fetch-negative-refspec.sh | 30 +++++++++++++++++ t/t7900-maintenance.sh | 14 ++++---- 6 files changed, 109 insertions(+), 38 deletions(-) base-commit: 89b43f80a514aee58b662ad606e6352e03eaeee4 Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-924%2Fderrickstolee%2Fmaintenance%2Frefspec-v3 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-924/derrickstolee/maintenance/refspec-v3 Pull-Request: https://github.com/gitgitgadget/git/pull/924 Range-diff vs v2: 1: 5aa0cb06c3f2 = 1: 4c0e983ba56f maintenance: simplify prefetch logic 2: d58a3e042ee8 < -: ------------ test-lib: use exact match for test_subcommand 3: 96388d949b98 < -: ------------ refspec: output a refspec item 4: bf296282323a < -: ------------ test-tool: test refspec input/output -: ------------ > 2: 7f488eea6dbd fetch: add --prefetch option 5: 9592224e3d42 ! 3: ed055d772452 maintenance: allow custom refspecs during prefetch @@ Metadata Author: Derrick Stolee ## Commit message ## - maintenance: allow custom refspecs during prefetch + maintenance: use 'git fetch --prefetch' - The prefetch task previously used the default refspec source plus a - custom refspec destination to avoid colliding with remote refs: + The 'prefetch' maintenance task previously forced the following refspec + for each remote: +refs/heads/*:refs/prefetch//* - However, some users customize their refspec to reduce how much data they - download from specific remotes. This can involve restrictive patterns - for fetching or negative patterns to avoid downloading some refs. + If a user has specified a more strict refspec for the remote, then this + prefetch task downloads more objects than necessary. - Modify fetch_remote() to iterate over the remote's refspec list and - translate that into the appropriate prefetch scenario. Specifically, - re-parse the raw form of the refspec into a new 'struct refspec' and - modify the 'dst' member to replace a leading "refs/" substring with - "refs/prefetch/", or prepend "refs/prefetch/" to 'dst' otherwise. - Negative refspecs do not have a 'dst' so they can be transferred to the - 'git fetch' command unmodified. - - This prefix change provides the benefit of keeping whatever collisions - may exist in the custom refspecs, if that is a desirable outcome. - - This changes the names of the refs that would be fetched by the default - refspec. Instead of "refs/prefetch//" they will now go - to "refs/prefetch/remotes//". While this is a change, it - is not a seriously breaking one: these refs are intended to be hidden - and not used. + The previous change introduced the '--prefetch' option to 'git fetch' + which manipulates the remote's refspec to place all resulting refs into + refs/prefetch/, with further partitioning based on the destinations of + those refspecs. Update the documentation to be more generic about the destination refs. - Do not mention custom refpecs explicitly, as that does not need to be + Do not mention custom refspecs explicitly, as that does not need to be highlighted in this documentation. The important part of placing refs in - refs/prefetch remains. + refs/prefetch/ remains. Reported-by: Tom Saeger Signed-off-by: Derrick Stolee ## Documentation/git-maintenance.txt ## -@@ Documentation/git-maintenance.txt: prefetch:: +@@ Documentation/git-maintenance.txt: commit-graph:: + prefetch:: + The `prefetch` task updates the object directory with the latest objects from all registered remotes. For each remote, a `git fetch` - command is run. The refmap is custom to avoid updating local or remote - branches (those in `refs/heads` or `refs/remotes`). Instead, the +- command is run. The refmap is custom to avoid updating local or remote +- branches (those in `refs/heads` or `refs/remotes`). Instead, the - remote refs are stored in `refs/prefetch//`. Also, tags are - not updated. -+ refs are stored in `refs/prefetch/`. Also, tags are not updated. ++ command is run. The configured refspec is modified to place all ++ requested refs within `refs/prefetch/`. Also, tags are not updated. + This is done to avoid disrupting the remote-tracking branches. The end users expect these refs to stay unmoved unless they initiate a fetch. With prefetch ## builtin/gc.c ## -@@ - #include "remote.h" - #include "object-store.h" - #include "exec-cmd.h" -+#include "refspec.h" - - #define FAILED_RUN "failed to run %s" - @@ builtin/gc.c: static int fetch_remote(struct remote *remote, void *cbdata) - { - struct maintenance_run_opts *opts = cbdata; struct child_process child = CHILD_PROCESS_INIT; -+ int i; child.git_cmd = 1; - strvec_pushl(&child.args, "fetch", remote->name, "--prune", "--no-tags", -@@ builtin/gc.c: static int fetch_remote(struct remote *remote, void *cbdata) +- strvec_pushl(&child.args, "fetch", remote->name, "--prune", "--no-tags", ++ strvec_pushl(&child.args, "fetch", remote->name, ++ "--prefetch", "--prune", "--no-tags", + "--no-write-fetch-head", "--recurse-submodules=no", +- "--refmap=", NULL); ++ NULL); + if (opts->quiet) strvec_push(&child.args, "--quiet"); - strvec_pushf(&child.args, "+refs/heads/*:refs/prefetch/%s/*", remote->name); -+ for (i = 0; i < remote->fetch.nr; i++) { -+ struct refspec_item replace; -+ struct refspec_item *rsi = &remote->fetch.items[i]; -+ struct strbuf new_dst = STRBUF_INIT; -+ size_t ignore_len = 0; -+ char *replace_string; -+ -+ if (rsi->negative) { -+ strvec_push(&child.args, remote->fetch.raw[i]); -+ continue; -+ } -+ -+ refspec_item_init(&replace, remote->fetch.raw[i], 1); -+ -+ /* -+ * If a refspec dst starts with "refs/" at the start, -+ * then we will replace "refs/" with "refs/prefetch/". -+ * Otherwise, we will prepend the dst string with -+ * "refs/prefetch/". -+ */ -+ if (!strncmp(replace.dst, "refs/", 5)) -+ ignore_len = 5; -+ -+ strbuf_addstr(&new_dst, "refs/prefetch/"); -+ strbuf_addstr(&new_dst, replace.dst + ignore_len); -+ free(replace.dst); -+ replace.dst = strbuf_detach(&new_dst, NULL); -+ -+ replace_string = refspec_item_format(&replace); -+ strvec_push(&child.args, replace_string); -+ free(replace_string); -+ -+ refspec_item_clear(&replace); -+ } - +- return !!run_command(&child); } + ## t/t7900-maintenance.sh ## @@ t/t7900-maintenance.sh: test_expect_success 'prefetch multiple remotes' ' + test_commit -C clone1 one && test_commit -C clone2 two && GIT_TRACE2_EVENT="$(pwd)/run-prefetch.txt" git maintenance run --task=prefetch 2>/dev/null && - fetchargs="--prune --no-tags --no-write-fetch-head --recurse-submodules=no --refmap= --quiet" && -- test_subcommand git fetch remote1 $fetchargs "+refs/heads/*:refs/prefetch/remote1/*" log && - ! grep "prefetch" log - ' - -+test_expect_success 'prefetch custom refspecs' ' -+ git -C clone1 branch -f special/fetched HEAD && -+ git -C clone1 branch -f special/secret/not-fetched HEAD && -+ -+ # create multiple refspecs for remote1 -+ git config --add remote.remote1.fetch "+refs/heads/special/fetched:refs/heads/fetched" && -+ git config --add remote.remote1.fetch "^refs/heads/special/secret/not-fetched" && -+ -+ GIT_TRACE2_EVENT="$(pwd)/prefetch-refspec.txt" git maintenance run --task=prefetch 2>/dev/null && -+ -+ fetchargs="--prune --no-tags --no-write-fetch-head --recurse-submodules=no --refmap= --quiet" && -+ -+ # skips second refspec because it is not a pattern type -+ rs1="+refs/heads/*:refs/prefetch/remotes/remote1/*" && -+ rs2="+refs/heads/special/fetched:refs/prefetch/heads/fetched" && -+ rs3="^refs/heads/special/secret/not-fetched" && -+ -+ test_subcommand git fetch remote1 $fetchargs "$rs1" "$rs2" "$rs3"