R3: --body-file <path>/- across body/comment carriers (#1474)

Co-authored-by: marcie <[email protected]>

packages/mosaic/framework/tools/git/issue-comment.sh

@@ -31,6 +31,7 @@ source "$SCRIPT_DIR/detect-platform.sh"
 # Parse arguments
 ISSUE_NUMBER=""
 COMMENT=""
+BODY_FILE=""
 LOGIN_OVERRIDE=""
 
 # Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
@@ -58,6 +59,12 @@ while [[ $# -gt 0 ]]; do
             COMMENT="$2"
             shift 2
             ;;
+        --body-file)
+            # R3: body from file (or '-' = stdin); mutually exclusive with --body.
+            [[ $# -ge 2 && "$2" != --* ]] || usage_error "option $1 requires a path (or - for stdin)"
+            BODY_FILE="$2"
+            shift 2
+            ;;
         -l|--login)
             [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LOGIN_OVERRIDE="$2"
@@ -83,6 +90,19 @@ while [[ $# -gt 0 ]]; do
     esac
 done
 
+# R3 (2026-08-29): resolve --body-file into COMMENT (file or stdin '-');
+# exclusive with an explicit --body/--comment value.
+if [[ -n "$BODY_FILE" ]]; then
+    [[ -z "$COMMENT" ]] || usage_error "--body-file and --body are mutually exclusive"
+    if [[ "$BODY_FILE" == "-" ]]; then
+        COMMENT=$(cat) || usage_error "could not read body from stdin"
+    else
+        [[ -r "$BODY_FILE" ]] || usage_error "body file not readable: $BODY_FILE"
+        COMMENT=$(cat "$BODY_FILE") || usage_error "could not read body file: $BODY_FILE"
+    fi
+fi
+
+
 if [[ -z "$ISSUE_NUMBER" ]]; then
     usage_error "issue number is required (-i/--issue)"
 fi