git: add git.colocate to colocate repos by default

Closes #2507.

Signed-off-by: Austin Seipp <aseipp@pobox.com>

CHANGELOG.md

@@ -125,6 +125,12 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 * `jj squash` now accepts a `--keep-emptied` option to keep the source commit.
 
+* The new configuration option `git.colocate=boolean` controls whether or not
+  Git repositories are colocated by default.
+
+* Both `jj git clone` and `jj git init` now take a `--no-colocate` flag to
+  disable colocation (in case `git.colocate` is set to `true`.)
+
 ### Fixed bugs
 
 * `jj git push` now ignores immutable commits when checking whether a

cli/src/commands/git/clone.rs

@@ -45,6 +45,9 @@ pub struct GitCloneArgs {
     /// Whether or not to colocate the Jujutsu repo with the git repo
     #[arg(long)]
     colocate: bool,
+    /// Disable colocation of the Jujutsu repo with the git repo
+    #[arg(long, conflicts_with = "colocate")]
+    no_colocate: bool,
 }
 
 fn absolute_git_source(cwd: &Path, source: &str) -> String {
@@ -105,6 +108,12 @@ pub fn cmd_git_clone(
     fs::create_dir_all(&wc_path)
         .map_err(|err| user_error_with_message(format!("Failed to create {wc_path_str}"), err))?;
 
+    let colocate = if command.settings().git_settings().colocate {
+        !args.no_colocate
+    } else {
+        args.colocate
+    };
+
     // Canonicalize because fs::remove_dir_all() doesn't seem to like e.g.
     // `/some/path/.`
     let canonical_wc_path: PathBuf = wc_path
@@ -113,7 +122,7 @@ pub fn cmd_git_clone(
     let clone_result = do_git_clone(
         ui,
         command,
-        args.colocate,
+        colocate,
         remote_name,
         &source,
         &canonical_wc_path,
@@ -121,7 +130,7 @@ pub fn cmd_git_clone(
     if clone_result.is_err() {
         let clean_up_dirs = || -> io::Result<()> {
             fs::remove_dir_all(canonical_wc_path.join(".jj"))?;
-            if args.colocate {
+            if colocate {
                 fs::remove_dir_all(canonical_wc_path.join(".git"))?;
             }
             if !wc_path_existed {

cli/src/commands/git/init.rs

@@ -53,6 +53,10 @@ pub struct GitInitArgs {
     #[arg(long, conflicts_with = "git_repo")]
     colocate: bool,
 
+    /// Disable colocation of the Jujutsu repo with the git repo
+    #[arg(long, conflicts_with = "colocate")]
+    no_colocate: bool,
+
     /// Specifies a path to an **existing** git repository to be
     /// used as the backing git repo for the newly created `jj` repo.
     ///
@@ -77,13 +81,13 @@ pub fn cmd_git_init(
         .and_then(|_| wc_path.canonicalize())
         .map_err(|e| user_error_with_message("Failed to create workspace", e))?;
 
-    do_init(
-        ui,
-        command,
-        &wc_path,
-        args.colocate,
-        args.git_repo.as_deref(),
-    )?;
+    let colocate = if command.settings().git_settings().colocate {
+        !args.no_colocate
+    } else {
+        args.colocate
+    };
+
+    do_init(ui, command, &wc_path, colocate, args.git_repo.as_deref())?;
 
     let relative_wc_path = file_util::relative_path(cwd, &wc_path);
     writeln!(

cli/src/config-schema.json

@@ -314,6 +314,11 @@
                     "type": "string",
                     "description": "The remote to which commits are pushed",
                     "default": "origin"
+                },
+                "colocate": {
+                    "type": "boolean",
+                    "description": "Whether to colocate the working copy with the git repository",
+                    "default": false
                 }
             }
         },

cli/tests/cli-reference@.md.snap

@@ -845,6 +845,7 @@ The Git repo will be a bare git repo stored inside the `.jj/` directory.
 ###### **Options:**
 
 * `--colocate` — Whether or not to colocate the Jujutsu repo with the git repo
+* `--no-colocate` — Disable colocation of the Jujutsu repo with the git repo
 
 
 
@@ -907,6 +908,7 @@ Create a new Git backed repo
    This is done by placing the backing git repo into a `.git` directory in the root of the `jj` repo along with the `.jj` directory. If the `.git` directory already exists, all the existing commits will be imported.
 
    This option is mutually exclusive with `--git-repo`.
+* `--no-colocate` — Disable colocation of the Jujutsu repo with the git repo
 * `--git-repo <GIT_REPO>` — Specifies a path to an **existing** git repository to be used as the backing git repo for the newly created `jj` repo.
 
    If the specified `--git-repo` path happens to be the same as the `jj` repo path (both .jj and .git directories are in the same working directory), then both `jj` and `git` commands will work on the same repo. This is called a co-located repo.

docs/config.md

@@ -732,6 +732,19 @@ signing.backends.ssh.allowed-signers = "/path/to/allowed-signers"
 
 ## Git settings
 
+### Default colocation
+
+When creating a git-backed Jujutsu repository, you can enable "colocation" which
+places the `.git` directory next to the `.jj` directory, allowing some amount of
+two-way interoperability.
+
+The setting `git.colocate` is a boolean option that controls whether or not the
+`jj git init` and `jj git clone` commands should create colocated repositories
+by default. By default, `git.colocate` is set to `false`.
+
+See [Co-located Jujutsu/Git repos](./
+git-compatibility.md#co-located-jujutsugit-repos) for more information.
+
 ### Default remotes for `jj git fetch` and `jj git push`
 
 By default, if a single remote exists it is used for `jj git fetch` and `jj git

lib/src/settings.rs

@@ -42,6 +42,7 @@ pub struct RepoSettings {
 pub struct GitSettings {
     pub auto_local_branch: bool,
     pub abandon_unreachable_commits: bool,
+    pub colocate: bool,
 }
 
 impl GitSettings {
@@ -51,6 +52,7 @@ impl GitSettings {
             abandon_unreachable_commits: config
                 .get_bool("git.abandon-unreachable-commits")
                 .unwrap_or(true),
+            colocate: config.get_bool("git.colocate").unwrap_or(false),
         }
     }
 }
@@ -60,6 +62,7 @@ impl Default for GitSettings {
         GitSettings {
             auto_local_branch: false,
             abandon_unreachable_commits: true,
+            colocate: false,
         }
     }
 }