Merge pull request #60 from instil/fix/pre-tool-use-hook-jq-dependency

fix: rewrite pre-tool-use hook for cross-platform compatibility

Author: calebwilson706

.github/hooks/pre-tool-use.sh

@@ -6,35 +6,104 @@
 # would prompt the user for permission on every state update — interrupting the
 # tutorial flow.
 #
-# Input format (per https://docs.github.com/en/copilot/tutorials/copilot-cli-hooks):
-#   { "toolName": "edit", "toolArgs": "{\"path\":\"...\"}" }
-# toolArgs is a JSON *string* that must be parsed separately.
+# Strategy: try node first (a guaranteed tutorial dependency, already used by
+# prompt-context.sh), then fall back to pure POSIX sed/tr for environments
+# where node is not on PATH.
+#
+# Works on: macOS, Linux, Git Bash (Windows), WSL.
+#
+# Input format (both variants are handled):
+#   toolArgs as JSON string: { "toolName": "edit", "toolArgs": "{\"path\":\"...\"}" }
+#   toolArgs as inline object: { "toolName": "edit", "toolArgs": { "path": "..." } }
 
-# Read hook input from stdin
+# Read all of stdin
 INPUT=$(cat)
 
-# Safely parse the structured hook payload. Default-deny if jq is unavailable.
-if ! command -v jq > /dev/null 2>&1; then
+# ---------------------------------------------------------------------------
+# Primary path: node (reliable JSON parsing, no regex fragility).
+# Input is passed via HOOK_INPUT env var to avoid heredoc stdin conflicts.
+# ---------------------------------------------------------------------------
+if command -v node > /dev/null 2>&1; then
+  RESULT=$(HOOK_INPUT="$INPUT" node -e "
+    var path = require('path');
+    var raw = process.env.HOOK_INPUT || '';
+    var data;
+    try { data = JSON.parse(raw); } catch(e) { process.exit(0); }
+
+    var toolName = data.toolName || '';
+    if (toolName !== 'edit' && toolName !== 'create') process.exit(0);
+
+    // toolArgs may be a JSON string or an inline object
+    var toolArgs = data.toolArgs || {};
+    if (typeof toolArgs === 'string') {
+      try { toolArgs = JSON.parse(toolArgs); } catch(e) { process.exit(0); }
+    }
+
+    var rawPath = (toolArgs.path || '').replace(/\\\\/g, '/');
+
+    // Normalise to a path relative to CWD (handles both absolute and relative
+    // paths, equivalent to Python's os.path.relpath).
+    var filePath = path.relative(process.cwd(), path.resolve(rawPath));
+
+    // Reject directory traversal
+    if (filePath.split(path.sep).indexOf('..') !== -1) process.exit(0);
+
+    // Normalise separator to forward slash (Windows path.sep is backslash)
+    filePath = filePath.replace(/\\\\/g, '/');
+
+    if (filePath === 'tutorial/state.json') {
+      process.stdout.write('{\"permissionDecision\": \"allow\"}\n');
+    }
+    process.exit(0);
+  ")
+  if [ -n "$RESULT" ]; then
+    printf '%s\n' "$RESULT"
+  fi
   exit 0
 fi
 
-TOOL_NAME="$(echo "$INPUT" | jq -r '.toolName // empty')"
-TOOL_ARGS_RAW="$(echo "$INPUT" | jq -r '.toolArgs // empty')"
-FILE_PATH="$(echo "$TOOL_ARGS_RAW" | jq -r '.path // empty' 2>/dev/null)"
-
-# Normalize the path to prevent directory traversal bypasses.
-# Uses python3 for portability (realpath -m/--relative-to is GNU-only, not available on macOS).
-NORMALIZED_PATH=""
-if [ -n "$FILE_PATH" ]; then
-  if command -v python3 > /dev/null 2>&1; then
-    NORMALIZED_PATH="$(python3 -c "import os; print(os.path.relpath('$FILE_PATH'))" 2>/dev/null)"
-  else
-    NORMALIZED_PATH="${FILE_PATH#./}"
-  fi
+# ---------------------------------------------------------------------------
+# Fallback: pure POSIX utilities (sed, tr) — no external dependencies
+# ---------------------------------------------------------------------------
+
+# Collapse to a single line and strip Windows \r
+SINGLE=$(printf '%s' "$INPUT" | tr -d '\n\r')
+
+# Extract toolName (top-level unescaped quotes — safe from toolArgs content)
+TOOL_NAME=$(printf '%s\n' "$SINGLE" | sed -n 's/.*"toolName"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p')
+case "$TOOL_NAME" in
+  edit|create) ;;
+  *) exit 0 ;;
+esac
+
+# Extract path — try escaped-string form first, then inline-object form
+FILE_PATH=$(printf '%s\n' "$SINGLE" | sed -n 's/.*\\"path\\"[[:space:]]*:[[:space:]]*\\"\([^"\\]*\)\\".*/\1/p')
+if [ -z "$FILE_PATH" ]; then
+  FILE_PATH=$(printf '%s\n' "$SINGLE" | sed -n 's/.*"path"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p')
 fi
+[ -z "$FILE_PATH" ] && exit 0
+
+# Normalize: backslashes → forward slashes, strip leading ./
+FILE_PATH=$(printf '%s' "$FILE_PATH" | tr '\\' '/')
+FILE_PATH="${FILE_PATH#./}"
+
+# Strip absolute CWD prefix so absolute paths become relative
+# e.g. /home/user/project/tutorial/state.json → tutorial/state.json
+# Use substring comparison (not glob pattern) to avoid misbehaving when
+# CWD contains glob metacharacters (*, ?, [).
+CWD=$(pwd | tr '\\' '/')
+PREFIX="$CWD/"
+if [ "${FILE_PATH:0:${#PREFIX}}" = "$PREFIX" ]; then
+  FILE_PATH="${FILE_PATH:${#PREFIX}}"
+fi
+
+# Reject directory traversal
+case "/$FILE_PATH/" in
+  */../*) exit 0 ;;
+esac
 
-if [ "$TOOL_NAME" = "edit" ] && [ "$NORMALIZED_PATH" = "tutorial/state.json" ]; then
-  echo '{"permissionDecision": "allow"}'
+if [ "$FILE_PATH" = "tutorial/state.json" ]; then
+  printf '{"permissionDecision": "allow"}\n'
 fi
 
 exit 0