[Skylark] Support dictionaries in structs when serializing them using struct.to_json.
Dictionaries are frequently used for generic configuration descriptions especially
given that `struct` is not allowed in build files.
In order to be JSON-compatible, only dictionaries with string keys are allowed.
Technically Python also allows integers and booleans by automatically converting
them to strings, but this is confusing and not necessarily a good thing to do.
Fixes #5542
Closes #5543.
PiperOrigin-RevId: 206049754
diff --git a/src/main/java/com/google/devtools/build/lib/packages/Info.java b/src/main/java/com/google/devtools/build/lib/packages/Info.java
index 775b8e0..4bc863b 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/Info.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/Info.java
@@ -30,6 +30,7 @@
import com.google.devtools.build.lib.syntax.EvalUtils;
import com.google.devtools.build.lib.syntax.Printer;
import com.google.devtools.build.lib.syntax.Runtime;
+import com.google.devtools.build.lib.syntax.SkylarkDict;
import com.google.devtools.build.lib.syntax.SkylarkList;
import com.google.devtools.build.lib.syntax.SkylarkType;
import com.google.protobuf.TextFormat;
@@ -218,8 +219,8 @@
return sb.toString();
}
- private void printProtoTextMessage(
- ClassObject object, StringBuilder sb, int indent, Location loc) throws EvalException {
+ private void printProtoTextMessage(ClassObject object, StringBuilder sb, int indent, Location loc)
+ throws EvalException {
// For determinism sort the fields alphabetically.
List<String> fields = new ArrayList<>(object.getFieldNames());
Collections.sort(fields);
@@ -260,8 +261,7 @@
}
private void printProtoTextMessage(
- String key, Object value, StringBuilder sb, int indent, Location loc)
- throws EvalException {
+ String key, Object value, StringBuilder sb, int indent, Location loc) throws EvalException {
if (value instanceof SkylarkList) {
for (Object item : ((SkylarkList) value)) {
// TODO(bazel-team): There should be some constraint on the fields of the structs
@@ -297,8 +297,7 @@
return sb.toString();
}
- private void printJson(
- Object value, StringBuilder sb, Location loc, String container, String key)
+ private void printJson(Object value, StringBuilder sb, Location loc, String container, String key)
throws EvalException {
if (value == Runtime.NONE) {
sb.append("null");
@@ -315,6 +314,29 @@
printJson(((ClassObject) value).getValue(field), sb, loc, "struct field", field);
}
sb.append("}");
+ } else if (value instanceof SkylarkDict) {
+ sb.append("{");
+ String join = "";
+ for (Map.Entry<?, ?> entry : ((SkylarkDict<?, ?>) value).entrySet()) {
+ sb.append(join);
+ join = ",";
+ if (!(entry.getKey() instanceof String)) {
+ String errorMessage =
+ "Keys must be a string but got a "
+ + EvalUtils.getDataTypeName(entry.getKey())
+ + " for "
+ + container;
+ if (key != null) {
+ errorMessage += " '" + key + "'";
+ }
+ throw new EvalException(loc, errorMessage);
+ }
+ sb.append("\"");
+ sb.append(entry.getKey());
+ sb.append("\":");
+ printJson(entry.getValue(), sb, loc, "dict value", String.valueOf(entry.getKey()));
+ }
+ sb.append("}");
} else if (value instanceof List) {
sb.append("[");
String join = "";
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/StructApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/StructApi.java
index 5c09749..49d90e5 100644
--- a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/StructApi.java
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/StructApi.java
@@ -60,8 +60,9 @@
name = "to_json",
doc =
"Creates a JSON string from the struct parameter. This method only works if all "
- + "struct elements (recursively) are strings, ints, booleans, other structs or a "
- + "list of these types. Quotes and new lines in strings are escaped. "
+ + "struct elements (recursively) are strings, ints, booleans, other structs, a "
+ + "list of these types or a dictionary with string keys and values of these types. "
+ + "Quotes and new lines in strings are escaped. "
+ "Examples:<br><pre class=language-python>"
+ "struct(key=123).to_json()\n# {\"key\":123}\n\n"
+ "struct(key=True).to_json()\n# {\"key\":true}\n\n"
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
index 5378df2..00f83d7 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
@@ -77,7 +77,7 @@
@Rule public ExpectedException thrown = ExpectedException.none();
@Before
- public final void createBuildFile() throws Exception {
+ public final void createBuildFile() throws Exception {
scratch.file(
"foo/BUILD",
"genrule(name = 'foo',",
@@ -329,7 +329,6 @@
+ " but got an element of type string.",
"c = provider()",
"attr.label_list(allow_files = True, providers = [['a', b], c])");
-
}
@Test
@@ -358,7 +357,6 @@
assertThat(attr.build("xxx").getAspectClasses()).containsExactly(aspect.getAspectClass());
}
-
@Test
public void testLabelListWithAspectsError() throws Exception {
checkErrorContains(
@@ -736,6 +734,7 @@
assertThat(c.hasAttr("a1", BuildType.LABEL_LIST)).isTrue();
assertThat(c.hasAttr("a2", Type.INTEGER)).isTrue();
}
+
@Test
public void testRuleAttributeFlag() throws Exception {
evalAndExport(
@@ -953,6 +952,21 @@
}
@Test
+ public void testJsonDictFields() throws Exception {
+ checkJson("struct(config={}).to_json()", "{\"config\":{}}");
+ checkJson("struct(config={'key': 'value'}).to_json()", "{\"config\":{\"key\":\"value\"}}");
+ checkErrorContains(
+ "Keys must be a string but got a int for struct field 'config'",
+ "struct(config={1:2}).to_json()");
+ checkErrorContains(
+ "Keys must be a string but got a int for dict value 'foo'",
+ "struct(config={'foo':{1:2}}).to_json()");
+ checkErrorContains(
+ "Keys must be a string but got a bool for struct field 'config'",
+ "struct(config={True: False}).to_json()");
+ }
+
+ @Test
public void testJsonEncoding() throws Exception {
checkJson("struct(name='value').to_json()", "{\"name\":\"value\"}");
checkJson("struct(name=['a', 'b']).to_json()", "{\"name\":[\"a\",\"b\"]}");
@@ -1537,8 +1551,6 @@
"aspect(impl, doc = 1)");
}
-
-
@Test
public void fancyExports() throws Exception {
evalAndExport(
@@ -1585,7 +1597,6 @@
SkylarkProvider p = (SkylarkProvider) lookup("p");
SkylarkInfo p1 = (SkylarkInfo) lookup("p1");
-
assertThat(p1.getProvider()).isEqualTo(p);
assertThat(lookup("x")).isEqualTo(1);
assertThat(lookup("y")).isEqualTo(2);
@@ -1602,7 +1613,6 @@
SkylarkProvider p = (SkylarkProvider) lookup("p");
SkylarkInfo p1 = (SkylarkInfo) lookup("p1");
-
assertThat(p1.getProvider()).isEqualTo(p);
assertThat(lookup("x")).isEqualTo(1);
assertThat(lookup("y")).isEqualTo(2);
@@ -1618,7 +1628,6 @@
SkylarkProvider p = (SkylarkProvider) lookup("p");
SkylarkInfo p1 = (SkylarkInfo) lookup("p1");
-
assertThat(p1.getProvider()).isEqualTo(p);
assertThat(lookup("y")).isEqualTo(2);
}
@@ -1657,7 +1666,6 @@
"unexpected keywords 'x', 'y', 'z' in call to p()");
}
-
@Test
public void starTheOnlyAspectArg() throws Exception {
checkEvalError("'*' must be the only string in 'attr_aspects' list",
