From 30920acd378ca91e0088b68d67b7095740654038 Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 9 Apr 2025 11:28:27 -0400
Subject: [PATCH 1/4] Port ipv6 fix

---
 .../java/build/buf/protovalidate/Ipv6.java    | 27 ++++++++++---------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/src/main/java/build/buf/protovalidate/Ipv6.java b/src/main/java/build/buf/protovalidate/Ipv6.java
index 52c276c0..cf64080e 100644
--- a/src/main/java/build/buf/protovalidate/Ipv6.java
+++ b/src/main/java/build/buf/protovalidate/Ipv6.java
@@ -14,6 +14,7 @@
 
 package build.buf.protovalidate;
 
+import java.text.ParseException;
 import java.util.ArrayList;
 import java.util.List;
 import javax.annotation.Nullable;
@@ -176,8 +177,12 @@ private boolean addressPart() {
         return false;
       }
 
-      if (this.h16()) {
-        continue;
+      try {
+        if (this.h16()) {
+          continue;
+        }
+      } catch (ParseException | NumberFormatException e) {
+        return false;
       }
 
       if (this.take(':')) {
@@ -191,6 +196,9 @@ private boolean addressPart() {
           if (this.take(':')) {
             return false;
           }
+        } else if (this.index == 1 || this.index == this.str.length()) {
+          // invalid - string cannot start or end on single colon
+          return false;
         }
         continue;
       }
@@ -266,7 +274,7 @@ private boolean dotted() {
    *
    * <p>Stores 16-bit value in pieces.
    */
-  private boolean h16() {
+  private boolean h16() throws ParseException, NumberFormatException {
     int start = this.index;
 
     while (this.index < this.str.length() && this.hexDig()) {}
@@ -280,18 +288,13 @@ private boolean h16() {
 
     if (str.length() > 4) {
       // too long
-      return false;
+      throw new ParseException("invalid hex", this.index);
     }
 
-    try {
-      int val = Integer.parseInt(str, 16);
+    int val = Integer.parseInt(str, 16);
 
-      this.pieces.add(val);
-      return true;
-    } catch (NumberFormatException nfe) {
-      // Error converting to number
-      return false;
-    }
+    this.pieces.add(val);
+    return true;
   }
 
   /**

From 5ac911b9f14073cfbccb8905d9281e00327c9c61 Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 9 Apr 2025 11:32:53 -0400
Subject: [PATCH 2/4] Comments

---
 src/main/java/build/buf/protovalidate/Ipv6.java | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/main/java/build/buf/protovalidate/Ipv6.java b/src/main/java/build/buf/protovalidate/Ipv6.java
index cf64080e..1e0ee1d4 100644
--- a/src/main/java/build/buf/protovalidate/Ipv6.java
+++ b/src/main/java/build/buf/protovalidate/Ipv6.java
@@ -272,7 +272,11 @@ private boolean dotted() {
    *
    * <pre>h16 = 1*4HEXDIG
    *
-   * <p>Stores 16-bit value in pieces.
+   * If 1-4 hex digits are found, the parsed 16-bit unsigned integer is stored
+   * in pieces and true is returned.
+   * If 0 hex digits are found, returns false.
+   * If more than 4 hex digits are found, a ParseException is thrown.
+   * If the found hex digits cannot be converted to an int, a NumberFormatException is raised.
    */
   private boolean h16() throws ParseException, NumberFormatException {
     int start = this.index;
@@ -282,15 +286,21 @@ private boolean h16() throws ParseException, NumberFormatException {
     String str = this.str.substring(start, this.index);
 
     if (str.isEmpty()) {
-      // too short
+      // too short, just return false
+      // this is not an error condition, it just means we didn't find any
+      // hex digits at the current position.
       return false;
     }
 
     if (str.length() > 4) {
       // too long
+      // this is an error condition, it means we found a string of more than
+      // four valid hex digits, which is invalid in ipv6 addresses.
       throw new ParseException("invalid hex", this.index);
     }
 
+    // Note that this will throw a NumberFormatException if string cannot be
+    // converted to an int.
     int val = Integer.parseInt(str, 16);
 
     this.pieces.add(val);

From 595cb76ca5438a123baeaa0eb9f2ba5b5ea092b8 Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 16 Apr 2025 10:33:58 -0400
Subject: [PATCH 3/4] change exception

---
 src/main/java/build/buf/protovalidate/Ipv6.java | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/main/java/build/buf/protovalidate/Ipv6.java b/src/main/java/build/buf/protovalidate/Ipv6.java
index 1e0ee1d4..a24fb6a3 100644
--- a/src/main/java/build/buf/protovalidate/Ipv6.java
+++ b/src/main/java/build/buf/protovalidate/Ipv6.java
@@ -181,7 +181,7 @@ private boolean addressPart() {
         if (this.h16()) {
           continue;
         }
-      } catch (ParseException | NumberFormatException e) {
+      } catch (IllegalStateException | NumberFormatException e) {
         return false;
       }
 
@@ -275,10 +275,10 @@ private boolean dotted() {
    * If 1-4 hex digits are found, the parsed 16-bit unsigned integer is stored
    * in pieces and true is returned.
    * If 0 hex digits are found, returns false.
-   * If more than 4 hex digits are found, a ParseException is thrown.
+   * If more than 4 hex digits are found, an IllegalStateException is thrown.
    * If the found hex digits cannot be converted to an int, a NumberFormatException is raised.
    */
-  private boolean h16() throws ParseException, NumberFormatException {
+  private boolean h16() throws IllegalStateException, NumberFormatException {
     int start = this.index;
 
     while (this.index < this.str.length() && this.hexDig()) {}
@@ -296,7 +296,7 @@ private boolean h16() throws ParseException, NumberFormatException {
       // too long
       // this is an error condition, it means we found a string of more than
       // four valid hex digits, which is invalid in ipv6 addresses.
-      throw new ParseException("invalid hex", this.index);
+      throw new IllegalStateException("invalid hex");
     }
 
     // Note that this will throw a NumberFormatException if string cannot be

From 7010808bd9d908a5e0d2035fb558a312a92f41e0 Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 16 Apr 2025 10:36:33 -0400
Subject: [PATCH 4/4] gen

---
 src/main/java/build/buf/protovalidate/Ipv6.java | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/main/java/build/buf/protovalidate/Ipv6.java b/src/main/java/build/buf/protovalidate/Ipv6.java
index a24fb6a3..239cd894 100644
--- a/src/main/java/build/buf/protovalidate/Ipv6.java
+++ b/src/main/java/build/buf/protovalidate/Ipv6.java
@@ -14,7 +14,6 @@
 
 package build.buf.protovalidate;
 
-import java.text.ParseException;
 import java.util.ArrayList;
 import java.util.List;
 import javax.annotation.Nullable;