--mount-git-worktree-common-dir silently ignored when devcontainer.json sets a custom workspaceMount #1243

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1. AvishayHirsh commented on Jun 8, 2026

   

   AvishayHirsh

   on Jun 8, 2026

   Last edited by AvishayHirsh

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   Workaround until this is fixed. The CLI skips the worktree common-dir mount whenever workspaceMount is set — so add it yourself with a mounts entry and --override-config. This script derives the correct mount for your worktree layout (sibling or nested) and brings the container up:

   #!/usr/bin/env bash
   # Worktree + custom workspaceMount: make in-container git work via an extra common-dir mount.
   # Run from the folder with your .devcontainer/ :
   #   bash fix-worktree-dc.sh                  -> just prints the "mounts" line to add
   #   bash fix-worktree-dc.sh --up             -> also brings the container up (devcontainer CLI)
   #   bash fix-worktree-dc.sh /workspaces --up -> non-/workspace workspaceMount target + bring up
   set -euo pipefail
   
   WMT=/workspace; APPLY=0
   for a in "$@"; do case "$a" in --up) APPLY=1;; *) WMT="$a";; esac; done
   
   ROOT="$(git rev-parse --show-toplevel)"
   [ -f "$ROOT/.git" ] || { echo "Not a git worktree — nothing to do."; exit 1; }
   MAIN_GIT="$(cd "$(git rev-parse --git-common-dir)" && pwd)"
   REL="$(sed -n 's/^gitdir: //p' "$ROOT/.git")"
   TARGET="$(python3 -c "import posixpath;print(posixpath.normpath('$WMT/$REL/../..'))")"
   echo "mounts entry:  source=$MAIN_GIT,target=$TARGET,type=bind"
   
   if [ "$APPLY" = 1 ]; then
     python3 - "$MAIN_GIT" "$TARGET" <<'PY'
   import json, re, sys
   s = re.sub(r",(\s*[}\]])", r"\1", re.sub(r"//.*", "", open(".devcontainer/devcontainer.json").read()))
   c = json.loads(s); c.setdefault("mounts", []).append(f"source={sys.argv[1]},target={sys.argv[2]},type=bind")
   json.dump(c, open("/tmp/dc-override.json","w"), indent=2)
   PY
     devcontainer up   --workspace-folder . --override-config /tmp/dc-override.json
     devcontainer exec --workspace-folder . -- bash -lc "git config --global --add safe.directory '*' && git status"
   fi

   CLI steps:

   npm i -g @devcontainers/cli                       # if you don't have it
   cd path/to/your/worktree/<...>/                   # the folder containing .devcontainer/
   bash fix-worktree-dc.sh --up                      # mounts main .git + brings the container up
   # then run anything in the container — git now resolves:
   devcontainer exec --workspace-folder . -- bash -lc "git status && ./gradlew build"

   The override goes to a throwaway file, so your committed devcontainer.json is untouched. (Prefer to make it permanent? run without --up, copy the printed mounts line into devcontainer.json.)

   Layout-agnostic — TARGET = normalize(<workspaceMount target> + <relative gitdir from .git> + /../..): nested worktree → /.git, sibling worktree → /<repo>/.git. Requires a relative-paths worktree (git worktree add --relative-paths, git ≥ 2.48).

   (VS Code / "Reopen in Container" variant: microsoft/vscode-remote-release#11478 (comment))
2. v-Mathiyarasy

   self-assigned this

   on Jun 11, 2026
3. Iggy Coloma (iggycoloma)

   added a commit that references this issue on Aug 2, 2026

   feat: agentic worktree dev environment (wt, devcontainer CLI, provisi…

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   4bb56ba
4. Dirk Louwers (dlouwers)

   added 2 commits that reference this issue on Oct 25, 2026

   Git inside a worktree's own devcontainer

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   ed6746d

   Git inside a worktree's own devcontainer

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   6205457