Disable git gc/maintenance on repositories opam maintains

master_changes.md

@@ -72,6 +72,7 @@ users)
 ## Sandbox
 
 ## VCS
+  * Disable git gc/maintenance on repositories opam maintains [#7073 @kit-ty-kate - partially fix #7031]
 
 ## Build
 
@@ -134,3 +135,5 @@ users)
 ## opam-format
 
 ## opam-core
+  * `OpamStd.Env`: Add the `raw = string array` type alias [#7073 @kit-ty-kate]
+  * `OpamStd.Env`: Add the `get_from_array` and `add_and_replace` functions [#7073 @kit-ty-kate]

src/core/opamStd.ml

@@ -741,15 +741,53 @@ module Env = struct
     module Map = Map.Make(M)
   end
 
+  type raw = string array
+
+  let raw_env = Unix.environment
+
+  let env_starts_with =
+    if Sys.win32 then
+      fun ~prefix x ->
+        let prefix = String.lowercase_ascii prefix in
+        let x = String.lowercase_ascii x in
+        OpamCompat.String.starts_with ~prefix x
+    else
+      OpamCompat.String.starts_with
+
+  let get_from_array env key =
+    let prefix = key ^ "=" in
+    let prefix_len = String.length prefix in
+    let exception Found of string in
+    try
+      for i = 0 to Array.length env - 1 do
+        let x = env.(i) in
+        if env_starts_with ~prefix x then
+          raise_notrace (Found x)
+      done;
+      None
+    with Found x ->
+      Some (String.sub x prefix_len (String.length x - prefix_len))
+
+  let add_and_replace env (key, value) =
+    let prefix = key ^ "=" in
+    let elem = prefix ^ value in
+    (* We always append [elem] to the environment instead of setting inplace
+       to avoid the double copy as we need to copy once anyway *)
+    let env = Array.append env [|elem|] in
+    for i = 0 to Array.length env - 2 do
+      let x = env.(i) in
+      if env_starts_with ~prefix x then
+        env.(i) <- elem;
+    done;
+    env
+
   let to_list env =
     List.rev_map (fun s ->
         match OpamString.cut_at s '=' with
         | None   -> s, ""
         | Some p -> p)
       (Array.to_list env)
 
-  let raw_env = Unix.environment
-
   let list =
     let lazy_env = lazy (to_list (raw_env ())) in
     fun () -> Lazy.force lazy_env

src/core/opamStd.mli

@@ -373,6 +373,28 @@ end
 
 module Env : sig
 
+  (** {3 Raw array functions} *)
+
+  type raw = string array
+
+  (** Same as {!Unix.environment} *)
+  val raw_env: unit -> raw
+
+  (** [get_from_array array key] returns the value of the first element
+      of [array] associated with [key]. Returns [None] if nothing was found. *)
+  val get_from_array: raw -> string -> string option
+
+  (** [add_and_replace array (key, value)] returns a fresh array containing
+      at least [key=value] and [array] where all the elements matching [key]
+      will be replaced by [key=value] as well.
+
+      This makes sure any applications will always associate [key] with [value]
+      as per POSIX.1-2024:
+      > If more than one string in an environment of a process has the same name,
+      > the consequences are undefined.
+      https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap08.html *)
+  val add_and_replace: raw -> (string * string) -> raw
+
   (** {3 Generic functions} *)
 
   (** Remove from a c-separated list of string the ones with the given prefix *)
@@ -436,7 +458,6 @@ module Env : sig
   val getopt_full: Name.t -> Name.t * string option
 
   val list: unit -> (Name.t * string) list
-  val raw_env: unit -> string array
 
   (** [cyg_env ~env ~cygbin ~git_location] returns [env] environment with its
       PATH variable updated with [git_location] and [cygbin] at the beginning,

src/repository/opamGit.ml

@@ -14,13 +14,49 @@ open OpamProcess.Job.Op
 
 (* let log fmt = OpamConsole.log "GIT" fmt *)
 
-let git_env = [|
-  "GIT_CONFIG_GLOBAL="^Filename.null;
-  "GIT_CONFIG_SYSTEM="^Filename.null;
-|]
+let git_env = [
+  "GIT_CONFIG_GLOBAL", Filename.null;
+  "GIT_CONFIG_SYSTEM", Filename.null;
+]
 
-let env () =
-  Array.append git_env (OpamProcess.default_env ())
+let git_config = [
+  "gc.autoDetach", "false";
+  "maintenance.autoDetach", "false";
+]
+
+let env =
+  let env = lazy begin
+    let env = OpamProcess.default_env () in
+    let env = List.fold_left OpamStd.Env.add_and_replace env git_env in
+    let config_count_name = "GIT_CONFIG_COUNT" in
+    let old_config_count =
+      let open OpamStd.Option.Op in
+      (OpamStd.Env.get_from_array env config_count_name >>= int_of_string_opt)
+      +! 0
+    in
+    let config_key_prefix = "GIT_CONFIG_KEY_" in
+    let config_value_prefix = "GIT_CONFIG_VALUE_" in
+    let new_config_count = old_config_count + List.length git_config in
+    let env =
+      OpamStd.Env.add_and_replace env
+        (config_count_name, Int.to_string new_config_count)
+    in
+    let rec aux env n = function
+      | [] -> env
+      | (key, value)::xs ->
+        let env =
+          OpamStd.Env.add_and_replace env
+            (config_key_prefix ^ Int.to_string n, key)
+        in
+        let env =
+          OpamStd.Env.add_and_replace env
+            (config_value_prefix ^ Int.to_string n, value)
+        in
+        aux env (n + 1) xs
+    in
+    aux env old_config_count git_config
+  end in
+  fun () -> Lazy.force env
 
 module VCS : OpamVCS.VCS = struct
 
@@ -45,6 +81,12 @@ module VCS : OpamVCS.VCS = struct
     OpamFilename.mkdir repo_root;
     OpamProcess.Job.of_list [
       git repo_root [ "init"; "--initial-branch=main" ];
+      (* Disable detachable jobs to avoid race conditions.
+         For example while building a package, if the user build steps
+         calls git they might end up spawning a maintenance job which would
+         then interfere with the removal of the build directory later. *)
+      git repo_root [ "config" ; "--local" ; "gc.autoDetach"; "false"];
+      git repo_root [ "config" ; "--local" ; "maintenance.autoDetach"; "false"];
       (* Enforce this option, it can break our use of git if set *)
       git repo_root [ "config" ; "--local" ; "fetch.prune"; "false"];
       (* We reset diff.noprefix to ensure we get a `-p1` patch and avoid <https://github.com/ocaml/opam/issues/3627>. *)

tests/reftests/action-disk.test

@@ -1271,6 +1271,8 @@ SYSTEM                          mkdir ${BASEDIR}/OPAM/install-from-git-pin-all/.
 Processing  1/1: [main-gpin: git]
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "init" "--initial-branch=main"
 - Initialized empty Git repository in ${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin/.git/
++ git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "config" "--local" "gc.autoDetach" "false"
++ git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "config" "--local" "maintenance.autoDetach" "false"
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "config" "--local" "fetch.prune" "false"
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "config" "--local" "diff.noprefix" "false"
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "config" "--local" "core.autocrlf" "false"
@@ -1630,6 +1632,8 @@ FILE(switch-config)             Wrote ${BASEDIR}/OPAM/install-from-git-pin-all/.
 FILE(switch-state)              Wrote ${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/backup/state-today.export atomically in 0.000s
 + git "-C" "${BASEDIR}/main-gpin" "symbolic-ref" "--quiet" "--short" "HEAD"
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "init" "--initial-branch=main"
++ git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "config" "--local" "gc.autoDetach" "false"
++ git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "config" "--local" "maintenance.autoDetach" "false"
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "config" "--local" "fetch.prune" "false"
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "config" "--local" "diff.noprefix" "false"
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin" "config" "--local" "core.autocrlf" "false"
@@ -1845,6 +1849,8 @@ SYSTEM                          mkdir ${OPAMTMP}
 SYSTEM                          mkdir ${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin.dev
 Processing  1/2: [main-gpin.dev: git]
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin.dev" "init" "--initial-branch=main"
++ git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin.dev" "config" "--local" "gc.autoDetach" "false"
++ git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin.dev" "config" "--local" "maintenance.autoDetach" "false"
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin.dev" "config" "--local" "fetch.prune" "false"
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin.dev" "config" "--local" "diff.noprefix" "false"
 + git "-C" "${BASEDIR}/OPAM/install-from-git-pin-all/.opam-switch/sources/main-gpin.dev" "config" "--local" "core.autocrlf" "false"

tests/reftests/download.test

@@ -237,6 +237,8 @@ SYSTEM                          mkdir ${OPAMTMP}
 SYSTEM                          mkdir ${BASEDIR}/OPAM/download/.opam-switch/sources/bar.1
 Processing  1/1: [bar.1: git]
 + git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/bar.1" "init" "--initial-branch=main"
++ git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/bar.1" "config" "--local" "gc.autoDetach" "false"
++ git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/bar.1" "config" "--local" "maintenance.autoDetach" "false"
 + git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/bar.1" "config" "--local" "fetch.prune" "false"
 + git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/bar.1" "config" "--local" "diff.noprefix" "false"
 + git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/bar.1" "config" "--local" "core.autocrlf" "false"
@@ -296,6 +298,8 @@ SYSTEM                          mkdir ${OPAMTMP}
 SYSTEM                          mkdir ${BASEDIR}/OPAM/download/.opam-switch/sources/qux.1
 Processing  1/1: [qux.1: git]
 + git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/qux.1" "init" "--initial-branch=main"
++ git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/qux.1" "config" "--local" "gc.autoDetach" "false"
++ git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/qux.1" "config" "--local" "maintenance.autoDetach" "false"
 + git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/qux.1" "config" "--local" "fetch.prune" "false"
 + git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/qux.1" "config" "--local" "diff.noprefix" "false"
 + git "-C" "${BASEDIR}/OPAM/download/.opam-switch/sources/qux.1" "config" "--local" "core.autocrlf" "false"

tests/reftests/repository.test

@@ -1060,6 +1060,8 @@ REPOSITORY                      update changes from git+file://${BASEDIR}/CHG
 Processing  1/1: [changes: git]
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "init" "--initial-branch=main"
 - Initialized empty Git repository in ${BASEDIR}/OPAM/repo/changes/.git/
++ git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "gc.autoDetach" "false"
++ git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "maintenance.autoDetach" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "fetch.prune" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "diff.noprefix" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "core.autocrlf" "false"
@@ -1114,6 +1116,8 @@ REPOSITORY                      update changes from git+file://${BASEDIR}/CHG
 Processing  1/1: [changes: git]
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "init" "--initial-branch=main"
 - Initialized empty Git repository in ${BASEDIR}/OPAM/repo/changes/.git/
++ git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "gc.autoDetach" "false"
++ git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "maintenance.autoDetach" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "fetch.prune" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "diff.noprefix" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "core.autocrlf" "false"
@@ -1236,6 +1240,8 @@ REPOSITORY                      update changes from git+file://${BASEDIR}/CHG
 Processing  1/1: [changes: git]
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "init" "--initial-branch=main"
 - Initialized empty Git repository in ${BASEDIR}/OPAM/repo/changes/.git/
++ git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "gc.autoDetach" "false"
++ git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "maintenance.autoDetach" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "fetch.prune" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "diff.noprefix" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "core.autocrlf" "false"
@@ -1287,6 +1293,8 @@ REPOSITORY                      update changes from git+file://${BASEDIR}/CHG
 Processing  1/1: [changes: git]
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "init" "--initial-branch=main"
 - Initialized empty Git repository in ${BASEDIR}/OPAM/repo/changes/.git/
++ git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "gc.autoDetach" "false"
++ git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "maintenance.autoDetach" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "fetch.prune" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "diff.noprefix" "false"
 + git "-C" "${BASEDIR}/OPAM/repo/changes" "config" "--local" "core.autocrlf" "false"