Properly escape property name and values when dumping app config

core/deployment/src/main/java/io/quarkus/deployment/configuration/tracker/ConfigTrackingWriter.java

@@ -99,12 +99,107 @@ public static void write(Map<String, String> readOptions, ConfigTrackingConfig c
      */
     public static void write(Writer writer, String name, String value) throws IOException {
         if (value != null) {
-            // escape the backslash before persisting
-            value = value.replace("\\", "\\\\");
+            name = toWritableValue(name, true, true);
+            value = toWritableValue(value, false, true);
             writer.write(name);
             writer.write("=");
             writer.write(value);
             writer.write(System.lineSeparator());
         }
     }
+
+    /*
+     * Converts unicodes to encoded &#92;uxxxx and escapes
+     * special characters with a preceding slash
+     */
+
+    /**
+     * Escapes characters that are expected to be escaped when {@link java.util.Properties} load
+     * files from disk.
+     *
+     * @param str property name or value
+     * @param escapeSpace whether to escape a whitespace (should be true for property names)
+     * @param escapeUnicode whether to converts unicodes to encoded &#92;uxxxx
+     * @return property name or value that can be written to a file
+     */
+    private static String toWritableValue(String str, boolean escapeSpace, boolean escapeUnicode) {
+        int len = str.length();
+        int bufLen = len * 2;
+        if (bufLen < 0) {
+            bufLen = Integer.MAX_VALUE;
+        }
+        StringBuilder outBuffer = new StringBuilder(bufLen);
+
+        for (int x = 0; x < len; x++) {
+            char aChar = str.charAt(x);
+            // Handle common case first, selecting largest block that
+            // avoids the specials below
+            if ((aChar > 61) && (aChar < 127)) {
+                if (aChar == '\\') {
+                    outBuffer.append('\\');
+                    outBuffer.append('\\');
+                    continue;
+                }
+                outBuffer.append(aChar);
+                continue;
+            }
+            switch (aChar) {
+                case ' ':
+                    if (x == 0 || escapeSpace) {
+                        outBuffer.append('\\');
+                    }
+                    outBuffer.append(' ');
+                    break;
+                case '\t':
+                    outBuffer.append('\\');
+                    outBuffer.append('t');
+                    break;
+                case '\n':
+                    outBuffer.append('\\');
+                    outBuffer.append('n');
+                    break;
+                case '\r':
+                    outBuffer.append('\\');
+                    outBuffer.append('r');
+                    break;
+                case '\f':
+                    outBuffer.append('\\');
+                    outBuffer.append('f');
+                    break;
+                case '=': // Fall through
+                case ':': // Fall through
+                case '#': // Fall through
+                case '!':
+                    outBuffer.append('\\');
+                    outBuffer.append(aChar);
+                    break;
+                default:
+                    if (((aChar < 0x0020) || (aChar > 0x007e)) & escapeUnicode) {
+                        outBuffer.append('\\');
+                        outBuffer.append('u');
+                        outBuffer.append(toHex((aChar >> 12) & 0xF));
+                        outBuffer.append(toHex((aChar >> 8) & 0xF));
+                        outBuffer.append(toHex((aChar >> 4) & 0xF));
+                        outBuffer.append(toHex(aChar & 0xF));
+                    } else {
+                        outBuffer.append(aChar);
+                    }
+            }
+        }
+        return outBuffer.toString();
+    }
+
+    /**
+     * Convert a nibble to a hex character
+     *
+     * @param nibble the nibble to convert.
+     */
+    private static char toHex(int nibble) {
+        return hexDigit[(nibble & 0xF)];
+    }
+
+    /** A table of hex digits */
+    private static final char[] hexDigit = {
+            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+    };
 }