Render git config on Codespaces without identity

Instead of skipping git config entirely on Codespaces, render the
template with aliases, colors, filters, and pager settings — just
strip the identity placeholders (EMAIL, SIGNINGKEY) and disable
gpgsign since Codespaces injects identity via ~/.gitconfig.

Update the test to verify the Codespaces path renders the config
with placeholders removed and gpgsign disabled.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: tarebyte

script/setup-git-config

@@ -23,17 +23,29 @@
 
 set -euo pipefail
 
-if [ -n "${CODESPACES:-}" ]; then
-    echo "Skipping git config setup on Codespaces"
-    exit 0
-fi
-
 REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
 GIT_TEMPLATE="$REPO_ROOT/templates/git-config.tmpl"
 GIT_CONFIG="$HOME/.config/git/config"
 IDENTITY_DIR="$HOME/.config/dotfiles"
 IDENTITY_FILE="$IDENTITY_DIR/identity.env"
 
+if [ -n "${CODESPACES:-}" ]; then
+    # Codespaces injects identity (name, email, credential helper) into
+    # ~/.gitconfig, so we only need the template for aliases, colors,
+    # filters, etc. Strip the identity/signing lines and render as-is.
+    mkdir -p "$HOME/.config/git"
+    tmp=$(mktemp "$GIT_CONFIG.XXXXXX")
+    trap 'rm -f "$tmp"' EXIT
+    sed -e '/{{EMAIL}}/d' \
+        -e '/{{SIGNINGKEY}}/d' \
+        -e 's/gpgsign = true/gpgsign = false/' \
+        "$GIT_TEMPLATE" > "$tmp"
+    mv "$tmp" "$GIT_CONFIG"
+    trap - EXIT
+    echo "Wrote $GIT_CONFIG (Codespaces mode — identity from ~/.gitconfig)"
+    exit 0
+fi
+
 mkdir -p "$HOME/.config/git"
 mkdir -p "$IDENTITY_DIR"
 chmod 700 "$IDENTITY_DIR"

script/test

@@ -215,8 +215,19 @@ test_git_config_codespaces_skip() {
     set -e
     mkdir -p "$sandbox/home"
     CODESPACES=1 HOME="$sandbox/home" "$REPO_ROOT/script/setup-git-config" > /dev/null
-    [ ! -f "$sandbox/home/.config/git/config" ] \
-        || { echo "codespaces path should skip rendering"; exit 1; }
+    [ -f "$sandbox/home/.config/git/config" ] \
+        || { echo "codespaces path should render config"; exit 1; }
+    # identity lines should be stripped
+    ! grep -q '{{EMAIL}}' "$sandbox/home/.config/git/config" \
+        || { echo "template placeholder {{EMAIL}} should be removed"; exit 1; }
+    ! grep -q '{{SIGNINGKEY}}' "$sandbox/home/.config/git/config" \
+        || { echo "template placeholder {{SIGNINGKEY}} should be removed"; exit 1; }
+    # gpgsign should be disabled
+    grep -q 'gpgsign = false' "$sandbox/home/.config/git/config" \
+        || { echo "gpgsign should be false in codespaces mode"; exit 1; }
+    # aliases should still be present
+    grep -q '\[alias\]' "$sandbox/home/.config/git/config" \
+        || { echo "aliases should be present in codespaces config"; exit 1; }
 }
 
 test_git_config_missing_email() {
@@ -255,7 +266,7 @@ echo
 echo "=== setup-git-config ==="
 run_test "basic template render"            test_git_config_basic_render
 run_test "sed metacharacter escaping"       test_git_config_sed_metachars
-run_test "codespaces skip"                  test_git_config_codespaces_skip
+run_test "codespaces render"                  test_git_config_codespaces_skip
 run_test "missing EMAIL errors"             test_git_config_missing_email
 run_test "missing SIGNINGKEY errors"        test_git_config_missing_signingkey