fs_write_new/fs_patch_new: no user interaction, always exit 0 with errors in output

1 files changed, 72 insertions, 0 deletions

diff --git a/tools/fs_patch_new.sh b/tools/fs_patch_new.sh
new file mode 100755
index 0000000..060c99a
--- /dev/null
+++ b/tools/fs_patch_new.sh
@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+set -uo pipefail
+
+# @describe Apply a patch to a file at the specified path.
+# This can be used to edit the file, without having to rewrite the whole file.
+# This tool NEVER requests user interaction and NEVER exits with a non-zero code.
+# Any error is reported in the tool output so the model can react within the same cycle.
+# @option --path! The path of the file to apply to
+# @option --contents! The patch to apply to the file
+#
+# Here is an example of a patch block that can be applied to modify the file to request the user's name:
+# --- a/hello.py
+# +++ b/hello.py
+# \@@ ... @@
+#  def hello():
+# -    print("Hello World")
+# +    name = input("What is your name? ")
+# +    print(f"Hello {name}")
+
+# @env LLM_OUTPUT=/dev/stdout The output path
+
+ROOT_DIR="${LLM_ROOT_DIR:-$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)}"
+OUT="${LLM_OUTPUT:-/dev/stdout}"
+
+# Report an error in the tool output and finish successfully (exit 0).
+err() {
+  echo "ERROR: $*" >> "$OUT"
+  exit 0
+}
+
+main() {
+  path="${argc_path:-}"
+  patch="${argc_contents:-}"
+
+  [[ -z "$path" ]]  && err "missing --path"
+  [[ -z "$patch" ]] && err "missing --contents"
+  [[ ! -e "$path" ]] && err "file not found: $path"
+  [[ ! -f "$path" ]] && err "not a regular file: $path"
+  [[ ! -r "$path" ]] && err "file not readable: $path"
+
+  new_contents=""
+  if ! new_contents="$(awk -f "$ROOT_DIR/utils/patch.awk" "$path" <(printf "%s" "$patch") 2>/tmp/fs_patch_new.err)"; then
+    msg="$(cat /tmp/fs_patch_new.err 2>/dev/null || true)"
+    err "patch apply failed for $path: ${msg:-unknown error}"
+  fi
+
+  # Show the diff (if any) so the model sees what is applied.
+  # NOTE: no guard_operation.sh here -> no user interaction.
+  printf "%s" "$new_contents" | git diff --no-index "$path" - >> "$OUT" 2>/dev/null || true
+
+  if ! printf "%s" "$new_contents" > "$path" 2>/tmp/fs_patch_new_write.err; then
+    msg="$(cat /tmp/fs_patch_new_write.err 2>/dev/null || true)"
+    err "failed to write patched file $path: ${msg:-unknown error}"
+  fi
+
+  echo "The patch applied to: $path" >> "$OUT"
+  exit 0
+}
+
+# Parse arguments with argc and run the tool in a subshell:
+# - argc calls `main`, which always ends with `exit 0`.
+# - If argc itself fails (missing/invalid arguments) its generated code prints the
+#   error to stderr and calls `exit 1`; running it in a subshell keeps that from
+#   terminating this script, and the message is captured into the tool output.
+# - The script itself always finishes with exit 0.
+argc_err="$(mktemp)"
+( eval "$(argc --argc-eval "$0" "$@" 2>/dev/null)" ) 2>"$argc_err"
+if [[ -s "$argc_err" ]]; then
+  { echo "ERROR: argument parsing failed:"; cat "$argc_err"; } >> "$OUT"
+fi
+rm -f "$argc_err"
+exit 0