skip empty SafeQuery from a List

google · Dec 28, 2024 · 3fb6796 · 3fb6796
1 parent 879be0e
commit 3fb6796
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Showing 2 changed files with 25 additions and 3 deletions.
diff --git a/mug-guava/src/main/java/com/google/mu/safesql/SafeQuery.java b/mug-guava/src/main/java/com/google/mu/safesql/SafeQuery.java
@@ -341,6 +341,10 @@ private SafeQuery guardDashExpression(Substring.Match placeholder) {
     return query.startsWith("-") && !placeholder.isImmediatelyBetween("(", ")") ? parenthesized() : this;
   }
 
+  private static Iterable<?> skipEmptySubqueries(Iterable<?> iterable) {
+    return Iterables.filter(iterable, v -> !(v instanceof SafeQuery && v.toString().isEmpty()));
+  }
+
   /**
    * An SPI class for subclasses to provide additional translation from
    * placeholder values to safe query strings.
@@ -411,7 +415,7 @@ protected SafeQuery translateLiteral(Substring.Match placeholder, Object value)
     private String fillInPlaceholder(Substring.Match placeholder, Object value) {
       validatePlaceholder(placeholder);
       if (value instanceof Iterable) {
-        Iterable<?> iterable = (Iterable<?>) value;
+        Iterable<?> iterable = skipEmptySubqueries((Iterable<?>) value);
         if (placeholder.isImmediatelyBetween("`", "`")) { // If backquoted, it's a list of symbols
           return String.join("`, `", Iterables.transform(iterable, v -> backquoted(placeholder, v)));
         }

diff --git a/mug-guava/src/test/java/com/google/mu/safesql/SafeQueryTest.java b/mug-guava/src/test/java/com/google/mu/safesql/SafeQueryTest.java
@@ -246,15 +246,33 @@ public void listOfUnquotedEnumsPlaceholder() {
   }
 
   @Test
-  public void listOfSafeBigQueriesPlaceholder() {
+  public void listOfSafeQueriesPlaceholder() {
     assertThat(
             template("SELECT foo FROM {tbls}")
                 .with(/* tbls */ asList(SafeQuery.of("a"), SafeQuery.of("b"))))
         .isEqualTo(SafeQuery.of("SELECT foo FROM a, b"));
   }
 
   @Test
-  public void listOfSafeBigQueries_disallowed() {
+  public void listOfSubqueries() {
+    assertThat(
+            SafeQuery.of(
+                "SELECT {exprs} FROM tbl", /* exprs */
+                asList(SafeQuery.of("123"), SafeQuery.of("foo"))))
+        .isEqualTo(SafeQuery.of("SELECT 123, foo FROM tbl"));
+  }
+
+  @Test
+  public void listOfSubqueries_emptySubqueryIgnored() {
+    assertThat(
+            SafeQuery.of(
+                "SELECT {exprs} FROM tbl", /* exprs */
+                asList(SafeQuery.of("123"), SafeQuery.EMPTY)))
+        .isEqualTo(SafeQuery.of("SELECT 123 FROM tbl"));
+  }
+
+  @Test
+  public void listOfSafeQueries_disallowed() {
     IllegalArgumentException thrown =
         assertThrows(
             IllegalArgumentException.class,