Fix incorrect int() example

Also add tests for leading "+" in int(<string>) form.

RELNOTES: None
PiperOrigin-RevId: 190507678

3 files changed, 17 insertions, 9 deletions

diff --git a/site/docs/skylark/spec.md b/site/docs/skylark/spec.md
index 53c0a5d482..5eedb45dfc 100644
--- a/site/docs/skylark/spec.md
+++ b/site/docs/skylark/spec.md
@@ -249,7 +249,7 @@ else:
 The Skylark integer type represents integers.  Its [type](#type) is `"int"`.
 
 Integers may be positive or negative. The precision is implementation-dependent.
-It is a dynamic error if a result is outside that the supported range.
+It is a dynamic error if a result is outside the supported range.
 Integers are totally ordered; comparisons follow mathematical
 tradition.
 
@@ -2327,12 +2327,15 @@ implies `hash(x) == hash(y)`.
 
 `int(x[, base])` interprets its argument as an integer.
 
-If x is an `int`, the result is x.
-If x is a `bool`, the result is 0 for `False` or 1 for `True`.
+If `x` is an `int`, the result is `x`.
+If `x` is a `bool`, the result is 0 for `False` or 1 for `True`.
 
-If x is a string, it is interpreted as an integer using the base argument
-(default is `10`). If base is `0`, x is interpreted like an integer literal, the
-base being inferred from an optional base prefix (for example `0o` or `0x`).
+If `x` is a string, it is interpreted as a sequence of digits in the specified
+base, decimal by default. If `base` is zero, `x` is interpreted like an integer
+literal, the base being inferred from an optional base marker such as `0b`,
+`0o`, or `0x` preceding the first digit. These markers may also be used if
+`base` is the corresponding base. Irrespective of base, the string may start
+with an optional `+` or `-` sign indicating the sign of the result.
 
 ```python
 int("21")          # 21
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/MethodLibrary.java b/src/main/java/com/google/devtools/build/lib/syntax/MethodLibrary.java
index 6f5e519a88..0597ebf1c9 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/MethodLibrary.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/MethodLibrary.java
@@ -1719,10 +1719,12 @@ public class MethodLibrary {
             + "<p>Examples:"
             + "<pre class=\"language-python\">"
             + "int(\"123\") == 123\n"
-            + "int(\"  -123  \") == -123\n"
+            + "int(\"-123\") == -123\n"
+            + "int(\"+123\") == 123\n"
             + "int(\"FF\", 16) == 255\n"
+            + "int(\"0xFF\", 16) == 255\n"
             + "int(\"10\", 0) == 10\n"
-            + "int(\"0x10\", 0) == 16"
+            + "int(\"-0x10\", 0) == -16"
             + "</pre>",
     parameters = {
       @Param(name = "x", type = Object.class, doc = "The string to convert."),
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/MethodLibraryTest.java b/src/test/java/com/google/devtools/build/lib/syntax/MethodLibraryTest.java
index 495978c0c3..ccf170fb47 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/MethodLibraryTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/MethodLibraryTest.java
@@ -986,7 +986,9 @@ public class MethodLibraryTest extends EvaluationTestCase {
         .testStatement("int('2147483647')", 2147483647)
         .testStatement("int('-2147483648')", -2147483648)
         // Leading zero allowed when not using base = 0.
-        .testStatement("int('016')", 16);
+        .testStatement("int('016')", 16)
+        // Leading plus sign allowed for strings.
+        .testStatement("int('+42')", 42);
   }
 
   @Test
@@ -1036,6 +1038,7 @@ public class MethodLibraryTest extends EvaluationTestCase {
     new BothModesTest()
         .testStatement("int('0b11', 0)", 3)
         .testStatement("int('-0b11', 0)", -3)
+        .testStatement("int('+0b11', 0)", 3)
         .testStatement("int('0B11', 2)", 3)
         .testStatement("int('0o11', 0)", 9)
         .testStatement("int('0O11', 8)", 9)