build: un-absorb git submodules before doing OCI build

.github/workflows/build-oci.yml

@@ -6,7 +6,7 @@ permissions:
   packages: write
   id-token: write
 jobs:
-  build:
+  build-oci-image:
     runs-on: edera-large
     strategy:
       fail-fast: false
@@ -18,6 +18,8 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           submodules: recursive
+      - run: ./unabsorb.sh
+        shell: bash
       - uses: sigstore/cosign-installer@3454372f43399081ed03b604cb2d021dabca52bb # v3.8.2
       - uses: docker/setup-qemu-action@29109295f81e9208d7d86ff1c6c12d2833863392 # v3.6.0
       - uses: docker/setup-buildx-action@b5ca514318bd6ebac0fb2aedd5d36ec1b5c232a2 # v3.10.0

unabsorb.sh

@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+super_top="$(git rev-parse --show-toplevel 2>/dev/null)" || {
+    echo "error: not inside a git worktree" >&2
+    exit 1
+}
+
+cd "${super_top}"
+
+# Collect all submodule paths first, recursively, then process deepest-first.
+mapfile -t submodules < <(
+    git submodule foreach --quiet --recursive 'printf "%s\n" "$displaypath"' \
+    | awk '{ depth=gsub(/\//, "/"); printf "%d\t%s\n", depth, $0 }' \
+    | sort -r -n -k1,1 \
+    | cut -f2-
+)
+
+if [[ ${#submodules[@]} -eq 0 ]]; then
+    echo "No submodules found."
+    exit 0
+fi
+
+for path in "${submodules[@]}"; do
+    echo "Processing ${path}"
+
+    cd "${super_top}/${path}"
+
+    if [[ ! -f .git ]]; then
+        echo "  skipping: .git is not a gitfile stub"
+        continue
+    fi
+
+    gitfile="$(< .git)"
+    case "${gitfile}" in
+        "gitdir: "*)
+            gitdir="${gitfile#gitdir: }"
+            ;;
+        *)
+            echo "  skipping: .git is not a recognized gitfile stub"
+            continue
+            ;;
+    esac
+
+    if [[ "${gitdir}" = /* ]]; then
+        src_gitdir="${gitdir}"
+    else
+        src_gitdir="$(realpath -m "${PWD}/${gitdir}")"
+    fi
+
+    if [[ ! -d "${src_gitdir}" ]]; then
+        echo "  error: source gitdir does not exist: ${src_gitdir}" >&2
+        exit 1
+    fi
+
+    rm -f .git
+    mv "${src_gitdir}" .git
+
+    # Remove core.worktree directly from config to avoid Git trying to
+    # resolve the stale absorbed worktree path during `git config`.
+    if [[ -f .git/config ]]; then
+        python3 - "$PWD/.git/config" <<'PY'
+import configparser
+import io
+import os
+import sys
+
+path = sys.argv[1]
+
+cp = configparser.RawConfigParser()
+cp.optionxform = str
+
+with open(path, "r", encoding="utf-8") as f:
+    data = f.read()
+
+cp.read_file(io.StringIO(data))
+
+changed = False
+if cp.has_section("core") and cp.has_option("core", "worktree"):
+    cp.remove_option("core", "worktree")
+    changed = True
+    if not cp.items("core"):
+        cp.remove_section("core")
+
+if changed:
+    with open(path, "w", encoding="utf-8") as f:
+        cp.write(f)
+PY
+    fi
+
+    echo "  moved ${src_gitdir} -> ${PWD}/.git"
+done