completion: cache the path to the repository

After the previous changes in this series there are only a handful of
$(__gitdir) command substitutions left in the completion script, but
there is still a bit of room for improvements:

1. The command substitution involves the forking of a subshell,
which has considerable overhead on some platforms.

2. There are a few cases, where this command substitution is
executed more than once during a single completion, which means
multiple subshells and possibly multiple 'git rev-parse'
executions.  __gitdir() is invoked twice while completing refs
for e.g. 'git log', 'git rebase', 'gitk', or while completing
remote refs for 'git fetch' or 'git push'.

Both of these points can be addressed by using the
__git_find_repo_path() helper function introduced in the previous
commit:

1. __git_find_repo_path() stores the path to the repository in a
variable instead of printing it, so the command substitution
around the function can be avoided.  Or rather: the command
substitution should be avoided to make the new value of the
variable set inside the function visible to the callers.
(Yes, there is now a command substitution inside
__git_find_repo_path() around each 'git rev-parse', but that's
executed only if necessary, and only once per completion, see
point 2. below.)

2. $__git_repo_path, the variable holding the path to the
repository, is declared local in the toplevel completion
functions __git_main() and __gitk_main().  Thus, once set, the
path is visible in all completion functions, including all
subsequent calls to __git_find_repo_path(), meaning that they
wouldn't have to re-discover the path to the repository.

So call __git_find_repo_path() and use $__git_repo_path instead of the
$(__gitdir) command substitution to access paths in the .git
directory.  Turn tests checking __gitdir()'s repository discovery into
tests of __git_find_repo_path() such that only the tested function
changes but the expected results don't, ensuring that repo discovery
keeps working as it did before.

As __gitdir() is not used anymore in the completion script, mark it as
deprecated and direct users' attention to __git_find_repo_path() and
$__git_repo_path.  Yet keep four __gitdir() tests to ensure that it
handles success and failure of __git_find_repo_path() and that it
still handles its optional remote argument, because users' custom
completion scriptlets might depend on it.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 9b9526b48d2ebe03021ab19d301078b254c23c83..d2601aee944286e74b4df33403cce663cb253cb7 100644 (file)
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -39,6 +39,11 @@ esac
 # variable.
 __git_find_repo_path ()
 {
+       if [ -n "$__git_repo_path" ]; then
+               # we already know where it is
+               return
+       fi
+
        if [ -n "${__git_C_args-}" ]; then
                __git_repo_path="$(git "${__git_C_args[@]}" \
                        ${__git_dir:+--git-dir="$__git_dir"} \
@@ -56,6 +61,7 @@ __git_find_repo_path ()
        fi
 }
 
+# Deprecated: use __git_find_repo_path() and $__git_repo_path instead
 # __gitdir accepts 0 or 1 arguments (i.e., location)
 # returns location of .git repo
 __gitdir ()
@@ -350,10 +356,13 @@ __git_tags ()
 #    'git checkout's tracking DWIMery (optional; ignored, if set but empty).
 __git_refs ()
 {
-       local i hash dir="$(__gitdir)" track="${2-}"
+       local i hash dir track="${2-}"
        local list_refs_from=path remote="${1-}"
        local format refs pfx
 
+       __git_find_repo_path
+       dir="$__git_repo_path"
+
        if [ -z "$remote" ]; then
                if [ -z "$dir" ]; then
                        return
@@ -458,8 +467,8 @@ __git_refs_remotes ()
 
 __git_remotes ()
 {
-       local d="$(__gitdir)"
-       test -d "$d/remotes" && ls -1 "$d/remotes"
+       __git_find_repo_path
+       test -d "$__git_repo_path/remotes" && ls -1 "$__git_repo_path/remotes"
        __git remote
 }
 
@@ -957,8 +966,8 @@ __git_whitespacelist="nowarn warn error error-all fix"
 
 _git_am ()
 {
-       local dir="$(__gitdir)"
-       if [ -d "$dir"/rebase-apply ]; then
+       __git_find_repo_path
+       if [ -d "$__git_repo_path"/rebase-apply ]; then
                __gitcomp "--skip --continue --resolved --abort"
                return
        fi
@@ -1041,7 +1050,8 @@ _git_bisect ()
        local subcommands="start bad good skip reset visualize replay log run"
        local subcommand="$(__git_find_on_cmdline "$subcommands")"
        if [ -z "$subcommand" ]; then
-               if [ -f "$(__gitdir)"/BISECT_START ]; then
+               __git_find_repo_path
+               if [ -f "$__git_repo_path"/BISECT_START ]; then
                        __gitcomp "$subcommands"
                else
                        __gitcomp "replay start"
@@ -1146,8 +1156,8 @@ _git_cherry ()
 
 _git_cherry_pick ()
 {
-       local dir="$(__gitdir)"
-       if [ -f "$dir"/CHERRY_PICK_HEAD ]; then
+       __git_find_repo_path
+       if [ -f "$__git_repo_path"/CHERRY_PICK_HEAD ]; then
                __gitcomp "--continue --quit --abort"
                return
        fi
@@ -1538,10 +1548,10 @@ __git_log_date_formats="relative iso8601 rfc2822 short local default raw"
 _git_log ()
 {
        __git_has_doubledash && return
+       __git_find_repo_path
 
-       local g="$(__gitdir)"
        local merge=""
-       if [ -f "$g/MERGE_HEAD" ]; then
+       if [ -f "$__git_repo_path/MERGE_HEAD" ]; then
                merge="--merge"
        fi
        case "$cur" in
@@ -1788,11 +1798,12 @@ _git_push ()
 
 _git_rebase ()
 {
-       local dir="$(__gitdir)"
-       if [ -f "$dir"/rebase-merge/interactive ]; then
+       __git_find_repo_path
+       if [ -f "$__git_repo_path"/rebase-merge/interactive ]; then
                __gitcomp "--continue --skip --abort --quit --edit-todo"
                return
-       elif [ -d "$dir"/rebase-apply ] || [ -d "$dir"/rebase-merge ]; then
+       elif [ -d "$__git_repo_path"/rebase-apply ] || \
+            [ -d "$__git_repo_path"/rebase-merge ]; then
                __gitcomp "--continue --skip --abort --quit"
                return
        fi
@@ -2467,8 +2478,8 @@ _git_reset ()
 
 _git_revert ()
 {
-       local dir="$(__gitdir)"
-       if [ -f "$dir"/REVERT_HEAD ]; then
+       __git_find_repo_path
+       if [ -f "$__git_repo_path"/REVERT_HEAD ]; then
                __gitcomp "--continue --quit --abort"
                return
        fi
@@ -2865,9 +2876,10 @@ __gitk_main ()
        __git_has_doubledash && return
 
        local __git_repo_path
-       local g="$(__gitdir)"
+       __git_find_repo_path
+
        local merge=""
-       if [ -f "$g/MERGE_HEAD" ]; then
+       if [ -f "$__git_repo_path/MERGE_HEAD" ]; then
                merge="--merge"
        fi
        case "$cur" in

diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 1816ed2e059d14a4cde86f94951bbe5b40c904df..d711bef2402cb7abd69c0bbcec49f7faba2530dd 100755 (executable)
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -131,213 +131,217 @@ else
        ROOT="$(pwd)"
 fi
 
-test_expect_success 'setup for __gitdir tests' '
+test_expect_success 'setup for __git_find_repo_path/__gitdir tests' '
        mkdir -p subdir/subsubdir &&
+       mkdir -p non-repo &&
        git init otherrepo
 '
 
-test_expect_success '__gitdir - from command line (through $__git_dir)' '
+test_expect_success '__git_find_repo_path - from command line (through $__git_dir)' '
        echo "$ROOT/otherrepo/.git" >expected &&
        (
                __git_dir="$ROOT/otherrepo/.git" &&
-               __gitdir >"$actual"
-       ) &&
-       test_cmp expected "$actual"
-'
-
-test_expect_success '__gitdir - repo as argument' '
-       echo "otherrepo/.git" >expected &&
-       (
-               __gitdir "otherrepo" >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - remote as argument' '
-       echo "remote" >expected &&
-       (
-               __gitdir "remote" >"$actual"
-       ) &&
-       test_cmp expected "$actual"
-'
-
-test_expect_success '__gitdir - .git directory in cwd' '
+test_expect_success '__git_find_repo_path - .git directory in cwd' '
        echo ".git" >expected &&
        (
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - .git directory in parent' '
+test_expect_success '__git_find_repo_path - .git directory in parent' '
        echo "$ROOT/.git" >expected &&
        (
                cd subdir/subsubdir &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - cwd is a .git directory' '
+test_expect_success '__git_find_repo_path - cwd is a .git directory' '
        echo "." >expected &&
        (
                cd .git &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - parent is a .git directory' '
+test_expect_success '__git_find_repo_path - parent is a .git directory' '
        echo "$ROOT/.git" >expected &&
        (
                cd .git/refs/heads &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - $GIT_DIR set while .git directory in cwd' '
+test_expect_success '__git_find_repo_path - $GIT_DIR set while .git directory in cwd' '
        echo "$ROOT/otherrepo/.git" >expected &&
        (
                GIT_DIR="$ROOT/otherrepo/.git" &&
                export GIT_DIR &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - $GIT_DIR set while .git directory in parent' '
+test_expect_success '__git_find_repo_path - $GIT_DIR set while .git directory in parent' '
        echo "$ROOT/otherrepo/.git" >expected &&
        (
                GIT_DIR="$ROOT/otherrepo/.git" &&
                export GIT_DIR &&
                cd subdir &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - from command line while "git -C"' '
+test_expect_success '__git_find_repo_path - from command line while "git -C"' '
        echo "$ROOT/.git" >expected &&
        (
                __git_dir="$ROOT/.git" &&
                __git_C_args=(-C otherrepo) &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - relative dir from command line and "git -C"' '
+test_expect_success '__git_find_repo_path - relative dir from command line and "git -C"' '
        echo "$ROOT/otherrepo/.git" >expected &&
        (
                cd subdir &&
                __git_dir="otherrepo/.git" &&
                __git_C_args=(-C ..) &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - $GIT_DIR set while "git -C"' '
+test_expect_success '__git_find_repo_path - $GIT_DIR set while "git -C"' '
        echo "$ROOT/.git" >expected &&
        (
                GIT_DIR="$ROOT/.git" &&
                export GIT_DIR &&
                __git_C_args=(-C otherrepo) &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - relative dir in $GIT_DIR and "git -C"' '
+test_expect_success '__git_find_repo_path - relative dir in $GIT_DIR and "git -C"' '
        echo "$ROOT/otherrepo/.git" >expected &&
        (
                cd subdir &&
                GIT_DIR="otherrepo/.git" &&
                export GIT_DIR &&
                __git_C_args=(-C ..) &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - "git -C" while .git directory in cwd' '
+test_expect_success '__git_find_repo_path - "git -C" while .git directory in cwd' '
        echo "$ROOT/otherrepo/.git" >expected &&
        (
                __git_C_args=(-C otherrepo) &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - "git -C" while cwd is a .git directory' '
+test_expect_success '__git_find_repo_path - "git -C" while cwd is a .git directory' '
        echo "$ROOT/otherrepo/.git" >expected &&
        (
                cd .git &&
                __git_C_args=(-C .. -C otherrepo) &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - "git -C" while .git directory in parent' '
+test_expect_success '__git_find_repo_path - "git -C" while .git directory in parent' '
        echo "$ROOT/otherrepo/.git" >expected &&
        (
                cd subdir &&
                __git_C_args=(-C .. -C otherrepo) &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - non-existing path in "git -C"' '
+test_expect_success '__git_find_repo_path - non-existing path in "git -C"' '
        (
                __git_C_args=(-C non-existing) &&
-               test_must_fail __gitdir >"$actual"
+               test_must_fail __git_find_repo_path &&
+               printf "$__git_repo_path" >"$actual"
        ) &&
        test_must_be_empty "$actual"
 '
 
-test_expect_success '__gitdir - non-existing path in $__git_dir' '
+test_expect_success '__git_find_repo_path - non-existing path in $__git_dir' '
        (
                __git_dir="non-existing" &&
-               test_must_fail __gitdir >"$actual"
+               test_must_fail __git_find_repo_path &&
+               printf "$__git_repo_path" >"$actual"
        ) &&
        test_must_be_empty "$actual"
 '
 
-test_expect_success '__gitdir - non-existing $GIT_DIR' '
+test_expect_success '__git_find_repo_path - non-existing $GIT_DIR' '
        (
                GIT_DIR="$ROOT/non-existing" &&
                export GIT_DIR &&
-               test_must_fail __gitdir >"$actual"
+               test_must_fail __git_find_repo_path &&
+               printf "$__git_repo_path" >"$actual"
        ) &&
        test_must_be_empty "$actual"
 '
 
-test_expect_success '__gitdir - gitfile in cwd' '
+test_expect_success '__git_find_repo_path - gitfile in cwd' '
        echo "$ROOT/otherrepo/.git" >expected &&
        echo "gitdir: $ROOT/otherrepo/.git" >subdir/.git &&
        test_when_finished "rm -f subdir/.git" &&
        (
                cd subdir &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - gitfile in parent' '
+test_expect_success '__git_find_repo_path - gitfile in parent' '
        echo "$ROOT/otherrepo/.git" >expected &&
        echo "gitdir: $ROOT/otherrepo/.git" >subdir/.git &&
        test_when_finished "rm -f subdir/.git" &&
        (
                cd subdir/subsubdir &&
-               __gitdir >"$actual"
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success SYMLINKS '__gitdir - resulting path avoids symlinks' '
+test_expect_success SYMLINKS '__git_find_repo_path - resulting path avoids symlinks' '
        echo "$ROOT/otherrepo/.git" >expected &&
        mkdir otherrepo/dir &&
        test_when_finished "rm -rf otherrepo/dir" &&
@@ -345,16 +349,57 @@ test_expect_success SYMLINKS '__gitdir - resulting path avoids symlinks' '
        test_when_finished "rm -f link" &&
        (
                cd link &&
+               __git_find_repo_path &&
+               echo "$__git_repo_path" >"$actual"
+       ) &&
+       test_cmp expected "$actual"
+'
+
+test_expect_success '__git_find_repo_path - not a git repository' '
+       (
+               cd non-repo &&
+               GIT_CEILING_DIRECTORIES="$ROOT" &&
+               export GIT_CEILING_DIRECTORIES &&
+               test_must_fail __git_find_repo_path &&
+               printf "$__git_repo_path" >"$actual"
+       ) &&
+       test_must_be_empty "$actual"
+'
+
+test_expect_success '__gitdir - finds repo' '
+       echo "$ROOT/.git" >expected &&
+       (
+               cd subdir/subsubdir &&
                __gitdir >"$actual"
        ) &&
        test_cmp expected "$actual"
 '
 
-test_expect_success '__gitdir - not a git repository' '
-       nongit test_must_fail __gitdir >"$actual" &&
+
+test_expect_success '__gitdir - returns error when cant find repo' '
+       (
+               __git_dir="non-existing" &&
+               test_must_fail __gitdir >"$actual"
+       ) &&
        test_must_be_empty "$actual"
 '
 
+test_expect_success '__gitdir - repo as argument' '
+       echo "otherrepo/.git" >expected &&
+       (
+               __gitdir "otherrepo" >"$actual"
+       ) &&
+       test_cmp expected "$actual"
+'
+
+test_expect_success '__gitdir - remote as argument' '
+       echo "remote" >expected &&
+       (
+               __gitdir "remote" >"$actual"
+       ) &&
+       test_cmp expected "$actual"
+'
+
 test_expect_success '__gitcomp - trailing space - options' '
        test_gitcomp "--re" "--dry-run --reuse-message= --reedit-message=
                --reset-author" <<-EOF