git-gui: respect core.hooksPath, falling back to .git/hooks

This is yet another patch from Git for Windows.

Changes since v3:

* Adjusted the commit message to reflect that this is no longer only about the hooks directory.
* Added a code comment to indicate how the list of keys was determined that are used for the gitdir priming.
* The gitdir cache is now re-primed upon F5.

Changes since v2:

* The paths returned by git rev-parse --git-path are now cached, and the cache is primed with the most common paths.

Changes since v1:

* Rather than a fine-grained override of gitdir just for the hooks path, we now spawn git rev-parse --git-path [...] every time gitdir is called with arguments. This makes the code safer, although at the cost of potentially many spawned processes.

Johannes Schindelin (1):
Make gitdir work with worktrees, respect core.hooksPath, etc

 git-gui.sh | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 58 insertions(+), 4 deletions(-)

base-commit: 60c60b627e81bf84e1cb01729d2ae882178f079d
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-361%2Fdscho%2Fgit-gui-hooks-path-v4
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-361/dscho/git-gui-hooks-path-v4
Pull-Request: https://github.com/gitgitgadget/git/pull/361

Range-diff vs v3:

1: 65c2fa33e1 ! 1: 2f55d6fb2a Fix gitdir e.g. to respect core.hooksPath
@@ -1,17 +1,21 @@
Author: Johannes Schindelin <[email protected]>

- Fix gitdir e.g. to respect core.hooksPath
+ Make gitdir work with worktrees, respect core.hooksPath, etc

- Since v2.9.0, Git knows about the config variable core.hookspath
- that allows overriding the path to the directory containing the
- Git hooks.
+ Since v2.9.0, Git knows about the config variable core.hookspath that
+ allows overriding the path to the directory containing the Git hooks.

- Since v2.10.0, the --git-path option respects that config
- variable, too, so we may just as well use that command.
+ Since v2.10.0, the --git-path option respects that config variable,
+ too, so we may just as well use that command.
+
+ Other paths inside .git are equally subject to differ from
+ <gitdir>/<path>, i.e. inside worktrees, where _some_ paths live in the
+ "gitdir" and some live in the "commondir" (i.e. the "gitdir" of the main
+ worktree).

For Git versions older than v2.5.0 (which was the first version to
- support the --git-path option for the rev-parse command), we
- simply fall back to the previous code.
+ support the --git-path option for the rev-parse command), we simply
+ fall back to the previous code.

An original patch handled only the hooksPath setting, however, during the code submission it was deemed better to fix all call to the gitdir
@@ -19,7 +23,9 @@

To avoid spawning a gazillion git rev-parse --git-path instances, we cache the returned paths, priming the cache upon startup in a single
- git rev-parse invocation with the known entries.
+ git rev-parse invocation with some paths (that have been
+ determined via a typical startup and via grepping the source code for
+ calls to the gitdir function).

This fixes https://github.com/git-for-windows/git/issues/1755

@@ -48,6 +54,8 @@
+
+ # --git-path is only supported since Git v2.5.0
+ if {[package vcompare $::_git_version 2.5.0] >= 0} {
++ # This list was generated from a typical startup as well as from
++ # grepping through Git GUI's source code.
+ set gitdir_keys [list \
+ CHERRY_PICK_HEAD FETCH_HEAD GITGUI_BCK GITGUI_EDITMSG \
+ GITGUI_MSG HEAD hooks hooks/prepare-commit-msg \
@@ -106,3 +114,21 @@
set _prefix [git rev-parse --show-prefix]
} err]} {
load_config 1
+@@
+ global HEAD PARENT MERGE_HEAD commit_type
+ global ui_index ui_workdir ui_comm
+ global rescan_active file_states
+- global repo_config
++ global repo_config _gitdir_cache
+
+ if {$rescan_active > 0 || ![lock_index read]} return
+
++ # Only re-prime gitdir cache on a full rescan
++ if {$after ne "ui_ready"} {
++ array unset _gitdir_cache
++ prime_gitdir_cache
++ }
++
+ repository_state newType newHEAD newMERGE_HEAD
+ if {[string match amend* $commit_type]
+ && $newType eq {normal}

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