From 16e72a1a9bbf182fac6686807e54bc846a9543ed Mon Sep 17 00:00:00 2001
From: Liam Miller-Cushon <cushon@google.com>
Date: Fri, 28 Jan 2022 08:43:12 -0800
Subject: [PATCH] Treat single-character upper case identifiers as
 UpperCamelCase

as a concession to Android `R` classes.

PiperOrigin-RevId: 424878859
---
 .../com/google/googlejavaformat/java/TypeNameClassifier.java | 2 +-
 .../google/googlejavaformat/java/TypeNameClassifierTest.java | 2 ++
 .../google/googlejavaformat/java/testdata/b26306390.input    | 3 +++
 .../google/googlejavaformat/java/testdata/b26306390.output   | 5 +++++
 4 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 core/src/test/resources/com/google/googlejavaformat/java/testdata/b26306390.input
 create mode 100644 core/src/test/resources/com/google/googlejavaformat/java/testdata/b26306390.output

diff --git a/core/src/main/java/com/google/googlejavaformat/java/TypeNameClassifier.java b/core/src/main/java/com/google/googlejavaformat/java/TypeNameClassifier.java
index 4e871a67f..21fae5f03 100644
--- a/core/src/main/java/com/google/googlejavaformat/java/TypeNameClassifier.java
+++ b/core/src/main/java/com/google/googlejavaformat/java/TypeNameClassifier.java
@@ -164,7 +164,7 @@ static JavaCaseFormat from(String name) {
         hasLowercase |= Character.isLowerCase(c);
       }
       if (firstUppercase) {
-        return hasLowercase ? UPPER_CAMEL : UPPERCASE;
+        return (hasLowercase || name.length() == 1) ? UPPER_CAMEL : UPPERCASE;
       } else {
         return hasUppercase ? LOWER_CAMEL : LOWERCASE;
       }
diff --git a/core/src/test/java/com/google/googlejavaformat/java/TypeNameClassifierTest.java b/core/src/test/java/com/google/googlejavaformat/java/TypeNameClassifierTest.java
index 9d1e00a18..3270bc64e 100644
--- a/core/src/test/java/com/google/googlejavaformat/java/TypeNameClassifierTest.java
+++ b/core/src/test/java/com/google/googlejavaformat/java/TypeNameClassifierTest.java
@@ -43,6 +43,7 @@ public void caseFormat() throws Exception {
     assertThat(JavaCaseFormat.from("a_$")).isEqualTo(JavaCaseFormat.LOWERCASE);
     assertThat(JavaCaseFormat.from("_")).isEqualTo(JavaCaseFormat.LOWERCASE);
     assertThat(JavaCaseFormat.from("_A")).isEqualTo(JavaCaseFormat.UPPERCASE);
+    assertThat(JavaCaseFormat.from("A")).isEqualTo(JavaCaseFormat.UPPER_CAMEL);
   }
 
   private static Optional<Integer> getPrefix(String qualifiedName) {
@@ -62,6 +63,7 @@ public void typePrefixLength() {
     assertThat(getPrefix("ClassName.CONST")).hasValue(1);
     assertThat(getPrefix("ClassName.varName")).hasValue(1);
     assertThat(getPrefix("ClassName.Inner.varName")).hasValue(2);
+    assertThat(getPrefix("com.R.foo")).hasValue(2);
   }
 
   @Test
diff --git a/core/src/test/resources/com/google/googlejavaformat/java/testdata/b26306390.input b/core/src/test/resources/com/google/googlejavaformat/java/testdata/b26306390.input
new file mode 100644
index 000000000..da6c01b01
--- /dev/null
+++ b/core/src/test/resources/com/google/googlejavaformat/java/testdata/b26306390.input
@@ -0,0 +1,3 @@
+class B26306390 {
+  int resourceId = com.some.extremely.verbose.pkg.name.R.string.some_extremely_long_resource_identifier_that_exceeds_the_column_limit;
+}
diff --git a/core/src/test/resources/com/google/googlejavaformat/java/testdata/b26306390.output b/core/src/test/resources/com/google/googlejavaformat/java/testdata/b26306390.output
new file mode 100644
index 000000000..a21772f8f
--- /dev/null
+++ b/core/src/test/resources/com/google/googlejavaformat/java/testdata/b26306390.output
@@ -0,0 +1,5 @@
+class B26306390 {
+  int resourceId =
+      com.some.extremely.verbose.pkg.name.R.string
+          .some_extremely_long_resource_identifier_that_exceeds_the_column_limit;
+}