Merge branch 'ar/submodule-gitdir-tweak' into seen

Avoid local submodule repository directory paths overlapping with
each other by encoding submodule names before using them as path
components.

* ar/submodule-gitdir-tweak:
  submodule: error out if gitdir name is too long
  submodule: encode gitdir paths to avoid conflicts
  strbuf: bring back is_rfc3986_unreserved
  submodule: add gitdir path config override
  submodule--helper: use submodule_name_to_gitdir in add_submodule

diff --cc Documentation/config/extensions.adoc
index 532456644b770e7f9a8d15b5eaac9eef143a5315,0f01b2871272c0cdbdc13eb624f67a9eb723da51..2235d565f5332b3ab044560edeab609bb580cfb2
--- 1/Documentation/config/extensions.adoc
--- 2/Documentation/config/extensions.adoc
+++ b/Documentation/config/extensions.adoc
@@@ -73,7 -69,16 +73,16 @@@ relativeWorktrees::
        repaired with either the `--relative-paths` option or with the
        `worktree.useRelativePaths` config set to `true`.
  
 -submoduleEncoding::
++submoduleEncoding:::
+       If enabled, submodule gitdir paths are encoded to avoid filesystem
+       conflicts due to nested gitdirs or case insensitivity. For now, only
+       url-encoding (rfc3986) is available, with a small addition to encode
+       uppercase to lowercase letters (`A  -> _a`, `B -> _b` and so on).
+       Other encoding or hashing methods may be added in the future.
+       Any preexisting non-encoded submodule gitdirs are used as-is, to
+       ease migration and reduce risk of gitdirs not being recognized.
+ 
 -worktreeConfig::
 +worktreeConfig:::
        If enabled, then worktrees will load config settings from the
        `$GIT_DIR/config.worktree` file in addition to the
        `$GIT_COMMON_DIR/config` file. Note that `$GIT_COMMON_DIR` and

diff --cc Makefile
Simple merge

diff --cc builtin/submodule--helper.c
Simple merge

diff --cc meson.build
Simple merge

diff --cc repository.h
Simple merge

diff --cc setup.c
Simple merge

diff --cc submodule.c
Simple merge

diff --cc t/meson.build
Simple merge

diff --cc t/t9902-completion.sh
Simple merge