From fa8c21cd688007f2eef5e9806f1482e836262eaa Mon Sep 17 00:00:00 2001
From: Sam Berlin <sameb@google.com>
Date: Wed, 19 Apr 2023 14:30:54 -0700
Subject: [PATCH] Fix Guice's dependence on the system line separator by never
 using the system line separator and always using \n explicitly. (We were
 previously inconsistent: many places used \n, and many other places used %n
 with a formatter, which would end up being the system line separator.) This
 allows tests to pass on Windows, where the line separator is different. Also
 update tests to do a run with the windows line separator, to catch
 regressions. Fixes #1213.

PiperOrigin-RevId: 525552063
---
 core/pom.xml                                  |  9 +++++++
 .../internal/BindingAlreadySetError.java      |  2 +-
 .../internal/ChildBindingAlreadySetError.java |  6 ++---
 .../internal/DuplicateElementError.java       | 10 ++++----
 .../inject/internal/DuplicateMapKeyError.java | 10 ++++----
 .../com/google/inject/internal/Errors.java    | 24 +++++++++----------
 .../internal/InternalProvisionException.java  |  6 ++---
 .../com/google/inject/internal/Messages.java  |  4 ++--
 .../internal/MissingConstructorError.java     | 12 +++++-----
 .../internal/MissingImplementationError.java  |  2 +-
 .../MissingImplementationErrorHints.java      | 14 +++++------
 .../ProvisionListenerStackCallback.java       |  2 +-
 .../google/inject/internal/RealMapBinder.java |  8 +++----
 .../inject/internal/ScopeNotFoundError.java   |  2 +-
 .../inject/internal/SingletonScope.java       |  8 +++----
 .../inject/internal/SourceFormatter.java      | 18 +++++++-------
 .../inject/spi/BindingSourceRestriction.java  |  2 +-
 .../com/google/inject/spi/ErrorDetail.java    |  6 ++---
 core/src/com/google/inject/util/Modules.java  |  4 ++--
 core/test/com/google/inject/BUILD             | 19 +++++++++++++++
 .../google/inject/internal/MessagesTest.java  |  2 +-
 21 files changed, 99 insertions(+), 71 deletions(-)

diff --git a/core/pom.xml b/core/pom.xml
index a42cca1127..57ddc8f217 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -129,6 +129,15 @@
               <argLine>-Dguice_bytecode_gen_option=DISABLED</argLine>
             </configuration>
           </execution>
+          <execution>
+            <id>with-windows-line-separators</id>
+            <phase>test</phase>
+            <goals><goal>test</goal></goals>
+            <configuration>
+              <!-- enable ShowHiddenFrames to help tests find AOP frames on Java17 -->
+              <argLine>-Dline.separator='\r\n' -XX:+UnlockDiagnosticVMOptions -XX:+ShowHiddenFrames</argLine>
+            </configuration>
+          </execution>
         </executions>
       </plugin>
       <!--
diff --git a/core/src/com/google/inject/internal/BindingAlreadySetError.java b/core/src/com/google/inject/internal/BindingAlreadySetError.java
index ba508f8475..db513ebd1c 100644
--- a/core/src/com/google/inject/internal/BindingAlreadySetError.java
+++ b/core/src/com/google/inject/internal/BindingAlreadySetError.java
@@ -39,7 +39,7 @@ public void formatDetail(List<ErrorDetail<?>> mergeableErrors, Formatter formatt
             .map(e -> ((BindingAlreadySetError) e).binding.getSource())
             .map(ImmutableList::of)
             .collect(Collectors.toList()));
-    formatter.format("%n%s%n", Messages.bold("Bound at:"));
+    formatter.format("\n%s\n", Messages.bold("Bound at:"));
     for (int i = 0; i < sourcesList.size(); i++) {
       ErrorFormatter.formatSources(i + 1, sourcesList.get(i), formatter);
     }
diff --git a/core/src/com/google/inject/internal/ChildBindingAlreadySetError.java b/core/src/com/google/inject/internal/ChildBindingAlreadySetError.java
index f2a10b48c1..b2362ac53a 100644
--- a/core/src/com/google/inject/internal/ChildBindingAlreadySetError.java
+++ b/core/src/com/google/inject/internal/ChildBindingAlreadySetError.java
@@ -43,12 +43,12 @@ public boolean isMergeable(ErrorDetail<?> otherError) {
 
   @Override
   public void formatDetail(List<ErrorDetail<?>> mergeableErrors, Formatter formatter) {
-    formatter.format("%n%s%n", Messages.bold("Bound at:"));
+    formatter.format("\n%s\n", Messages.bold("Bound at:"));
     int index = 1;
     for (Object source : existingSources) {
       formatter.format("%-2s: ", index++);
       if (source.equals("")) {
-        formatter.format("as a just-in-time binding%n");
+        formatter.format("as a just-in-time binding\n");
       } else {
         new SourceFormatter(source, formatter, /* omitPreposition= */ true).format();
       }
@@ -63,7 +63,7 @@ public void formatDetail(List<ErrorDetail<?>> mergeableErrors, Formatter formatt
             .filter(list -> !list.isEmpty())
             .collect(Collectors.toList());
     if (!filteredSources.isEmpty()) {
-      formatter.format("%n%s%n", Messages.bold("Requested by:"));
+      formatter.format("\n%s\n", Messages.bold("Requested by:"));
       for (int i = 0; i < sourcesList.size(); i++) {
         ErrorFormatter.formatSources(i + 1, sourcesList.get(i), formatter);
       }
diff --git a/core/src/com/google/inject/internal/DuplicateElementError.java b/core/src/com/google/inject/internal/DuplicateElementError.java
index f6cd104e08..5c14b86723 100644
--- a/core/src/com/google/inject/internal/DuplicateElementError.java
+++ b/core/src/com/google/inject/internal/DuplicateElementError.java
@@ -38,7 +38,7 @@ private DuplicateElementError(
 
   @Override
   protected void formatDetail(List<ErrorDetail<?>> others, Formatter formatter) {
-    formatter.format("%n%s%n", Messages.bold("Duplicates:"));
+    formatter.format("\n%s\n", Messages.bold("Duplicates:"));
     int duplicateIndex = 1;
     for (Map.Entry<T, Collection<Element<T>>> entry : elements.asMap().entrySet()) {
       formatter.format("%-2s: ", duplicateIndex++);
@@ -49,8 +49,8 @@ protected void formatDetail(List<ErrorDetail<?>> others, Formatter formatter) {
                 .collect(Collectors.toSet());
         if (valuesAsString.size() == 1) {
           // String representation of the duplicates elements are the same, so only print out one.
-          formatter.format("Element: %s%n", Messages.redBold(valuesAsString.iterator().next()));
-          formatter.format("    Bound at:%n");
+          formatter.format("Element: %s\n", Messages.redBold(valuesAsString.iterator().next()));
+          formatter.format("    Bound at:\n");
           int index = 1;
           for (Element<T> element : entry.getValue()) {
             formatter.format("    %-2s: ", index++);
@@ -69,14 +69,14 @@ protected void formatDetail(List<ErrorDetail<?>> others, Formatter formatter) {
             } else {
               indent = true;
             }
-            formatter.format("Element: %s%n", Messages.redBold(element.value.toString()));
+            formatter.format("Element: %s\n", Messages.redBold(element.value.toString()));
             formatter.format("    Bound at: ");
             formatElement(element, formatter);
           }
         }
       }
     }
-    formatter.format("%n%s%n", Messages.bold("Multibinder declared at:"));
+    formatter.format("\n%s\n", Messages.bold("Multibinder declared at:"));
     // Multibinder source includes the key of the set. Filter it out since it's not useful in the
     // printed error stack.
     List<Object> filteredSource =
diff --git a/core/src/com/google/inject/internal/DuplicateMapKeyError.java b/core/src/com/google/inject/internal/DuplicateMapKeyError.java
index ad428b342d..4e617a90b4 100644
--- a/core/src/com/google/inject/internal/DuplicateMapKeyError.java
+++ b/core/src/com/google/inject/internal/DuplicateMapKeyError.java
@@ -27,11 +27,11 @@ final class DuplicateMapKeyError<K, V> extends InternalErrorDetail<DuplicateMapK
 
   @Override
   protected final void formatDetail(List<ErrorDetail<?>> others, Formatter formatter) {
-    formatter.format("%n%s%n", Messages.bold("Duplicates:"));
+    formatter.format("\n%s\n", Messages.bold("Duplicates:"));
 
     for (Map.Entry<K, Collection<Binding<V>>> entry : duplicates.asMap().entrySet()) {
-      formatter.format("  Key: \"%s\"%n", Messages.redBold(entry.getKey().toString()));
-      formatter.format("  Bound at:%n");
+      formatter.format("  Key: \"%s\"\n", Messages.redBold(entry.getKey().toString()));
+      formatter.format("  Bound at:\n");
       int index = 1;
       for (Binding<V> binding : entry.getValue()) {
         formatter.format("    %-2s: ", index++);
@@ -42,10 +42,10 @@ protected final void formatDetail(List<ErrorDetail<?>> others, Formatter formatt
                 true)
             .format();
       }
-      formatter.format("%n");
+      formatter.format("\n");
     }
 
-    formatter.format("%s%n", Messages.bold("MapBinder declared at:"));
+    formatter.format("%s\n", Messages.bold("MapBinder declared at:"));
     ErrorFormatter.formatSources(getSources(), formatter);
   }
 
diff --git a/core/src/com/google/inject/internal/Errors.java b/core/src/com/google/inject/internal/Errors.java
index 2c584a8c2e..8f9570d43d 100644
--- a/core/src/com/google/inject/internal/Errors.java
+++ b/core/src/com/google/inject/internal/Errors.java
@@ -133,7 +133,7 @@ public Errors withSource(Object source) {
   public Errors aopDisabled(InterceptorBinding binding) {
     return addMessage(
         ErrorId.AOP_DISABLED,
-        "Binding interceptor is not supported when bytecode generation is disabled. %nInterceptor"
+        "Binding interceptor is not supported when bytecode generation is disabled. \nInterceptor"
             + " bound at: %s",
         binding.getSource());
   }
@@ -177,7 +177,7 @@ public Errors jitDisabled(Key<?> key) {
   public Errors jitDisabledInParent(Key<?> key) {
     return addMessage(
         ErrorId.JIT_DISABLED_IN_PARENT,
-        "Explicit bindings are required and %s would be bound in a parent injector.%n"
+        "Explicit bindings are required and %s would be bound in a parent injector.\n"
             + "Please add an explicit binding for it, either in the child or the parent.",
         key);
   }
@@ -197,7 +197,7 @@ public Errors converterReturnedNull(
       TypeConverterBinding typeConverterBinding) {
     return addMessage(
         ErrorId.CONVERTER_RETURNED_NULL,
-        "Received null converting '%s' (bound at %s) to %s%n using %s.",
+        "Received null converting '%s' (bound at %s) to %s\n using %s.",
         stringValue,
         convert(source),
         type,
@@ -212,8 +212,8 @@ public Errors conversionTypeError(
       Object converted) {
     return addMessage(
         ErrorId.CONVERSION_TYPE_ERROR,
-        "Type mismatch converting '%s' (bound at %s) to %s%n"
-            + " using %s.%n"
+        "Type mismatch converting '%s' (bound at %s) to %s\n"
+            + " using %s.\n"
             + " Converter returned %s.",
         stringValue,
         convert(source),
@@ -230,7 +230,7 @@ public Errors conversionError(
       RuntimeException cause) {
     return errorInUserCode(
         cause,
-        "Error converting '%s' (bound at %s) to %s%n using %s.%n Reason: %s",
+        "Error converting '%s' (bound at %s) to %s\n using %s.\n Reason: %s",
         stringValue,
         convert(source),
         type,
@@ -246,9 +246,9 @@ public Errors ambiguousTypeConversion(
       TypeConverterBinding b) {
     return addMessage(
         ErrorId.AMBIGUOUS_TYPE_CONVERSION,
-        "Multiple converters can convert '%s' (bound at %s) to %s:%n"
-            + " %s and%n"
-            + " %s.%n"
+        "Multiple converters can convert '%s' (bound at %s) to %s:\n"
+            + " %s and\n"
+            + " %s.\n"
             + " Please adjust your type converter configuration to avoid overlapping matches.",
         stringValue,
         convert(source),
@@ -315,7 +315,7 @@ public Errors scopeAnnotationOnAbstractType(
     return addMessage(
         ErrorId.SCOPE_ANNOTATION_ON_ABSTRACT_TYPE,
         "%s is annotated with %s, but scope annotations are not supported "
-            + "for abstract types.%n Bound at %s.",
+            + "for abstract types.\n Bound at %s.",
         type,
         scopeAnnotation,
         convert(source));
@@ -368,7 +368,7 @@ public Errors duplicateScopes(
       ScopeBinding existing, Class<? extends Annotation> annotationType, Scope scope) {
     return addMessage(
         ErrorId.DUPLICATE_SCOPES,
-        "Scope %s is already bound to %s at %s.%n Cannot bind %s.",
+        "Scope %s is already bound to %s at %s.\n Cannot bind %s.",
         existing.getScope(),
         annotationType,
         existing.getSource(),
@@ -503,7 +503,7 @@ public Errors errorNotifyingTypeListener(
       TypeListenerBinding listener, TypeLiteral<?> type, Throwable cause) {
     return errorInUserCode(
         cause,
-        "Error notifying TypeListener %s (bound at %s) of %s.%n Reason: %s",
+        "Error notifying TypeListener %s (bound at %s) of %s.\n Reason: %s",
         listener.getListener(),
         convert(listener.getSource()),
         type,
diff --git a/core/src/com/google/inject/internal/InternalProvisionException.java b/core/src/com/google/inject/internal/InternalProvisionException.java
index e121084979..4669327e91 100644
--- a/core/src/com/google/inject/internal/InternalProvisionException.java
+++ b/core/src/com/google/inject/internal/InternalProvisionException.java
@@ -124,7 +124,7 @@ public static InternalProvisionException errorInUserInjector(
     return errorInUserCode(
         ErrorId.ERROR_IN_USER_INJECTOR,
         cause,
-        "Error injecting %s using %s.%n Reason: %s",
+        "Error injecting %s using %s.\n Reason: %s",
         type,
         listener,
         cause);
@@ -142,7 +142,7 @@ public static InternalProvisionException errorNotifyingInjectionListener(
     return errorInUserCode(
         ErrorId.OTHER,
         cause,
-        "Error notifying InjectionListener %s of %s.%n Reason: %s",
+        "Error notifying InjectionListener %s of %s.\n Reason: %s",
         listener,
         type,
         cause);
@@ -191,7 +191,7 @@ static void onNullInjectedIntoNonNullableDependency(Object source, Dependency<?>
             : "the " + parameterName + " of " + memberStackTraceElement;
     throw InternalProvisionException.create(
             ErrorId.NULL_INJECTED_INTO_NON_NULLABLE,
-            "null returned by binding at %s%n but %s is not @Nullable",
+            "null returned by binding at %s\n but %s is not @Nullable",
             source,
             formattedDependency)
         .addSource(source);
diff --git a/core/src/com/google/inject/internal/Messages.java b/core/src/com/google/inject/internal/Messages.java
index a3b8cca9f2..667bcf5473 100644
--- a/core/src/com/google/inject/internal/Messages.java
+++ b/core/src/com/google/inject/internal/Messages.java
@@ -69,7 +69,7 @@ public static String format(String messageFormat, Object... arguments) {
 
   /** Returns the formatted message for an exception with the specified messages. */
   public static String formatMessages(String heading, Collection<Message> errorMessages) {
-    Formatter fmt = new Formatter().format(heading).format(":%n%n");
+    Formatter fmt = new Formatter().format(heading).format(":\n\n");
     int index = 1;
     boolean displayCauses = getOnlyCause(errorMessages) == null;
 
@@ -102,7 +102,7 @@ public static String formatMessages(String heading, Collection<Message> errorMes
               cause.getClass().getName(), causeIdx);
         }
       }
-      fmt.format("%n");
+      fmt.format("\n");
       index++;
     }
 
diff --git a/core/src/com/google/inject/internal/MissingConstructorError.java b/core/src/com/google/inject/internal/MissingConstructorError.java
index b655011816..b16b1e0dde 100644
--- a/core/src/com/google/inject/internal/MissingConstructorError.java
+++ b/core/src/com/google/inject/internal/MissingConstructorError.java
@@ -37,12 +37,12 @@ public boolean isMergeable(ErrorDetail<?> other) {
 
   @Override
   protected void formatDetail(List<ErrorDetail<?>> mergeableErrors, Formatter formatter) {
-    formatter.format("%n");
+    formatter.format("\n");
     Class<?> rawType = type.getRawType();
     if (atInjectRequired) {
       formatter.format(
           "Injector is configured to require @Inject constructors but %s does not have a @Inject"
-              + " annotated constructor.%n",
+              + " annotated constructor.\n",
           rawType);
     } else {
       Constructor<?> noArgConstructor = null;
@@ -53,22 +53,22 @@ protected void formatDetail(List<ErrorDetail<?>> mergeableErrors, Formatter form
       }
       if (noArgConstructor == null) {
         formatter.format(
-            "%s does not have a @Inject annotated constructor or a no-arg constructor.%n", rawType);
+            "%s does not have a @Inject annotated constructor or a no-arg constructor.\n", rawType);
       } else if (Modifier.isPrivate(noArgConstructor.getModifiers())
           && !Modifier.isPrivate(rawType.getModifiers())) {
         formatter.format(
             "%s has a private no-arg constructor but the class is not private. Guice can only use"
-                + " a private no-arg constructor if it is defined in a private class.%n",
+                + " a private no-arg constructor if it is defined in a private class.\n",
             rawType);
       }
     }
-    formatter.format("%n");
+    formatter.format("\n");
 
     List<List<Object>> sourcesList = new ArrayList<>();
     sourcesList.add(getSources());
     mergeableErrors.forEach(error -> sourcesList.add(error.getSources()));
 
-    formatter.format("%s%n", Messages.bold("Requested by:"));
+    formatter.format("%s\n", Messages.bold("Requested by:"));
     int sourceListIndex = 1;
     for (List<Object> sources : sourcesList) {
       ErrorFormatter.formatSources(sourceListIndex++, Lists.reverse(sources), formatter);
diff --git a/core/src/com/google/inject/internal/MissingImplementationError.java b/core/src/com/google/inject/internal/MissingImplementationError.java
index 2b48d00525..b504b88c27 100644
--- a/core/src/com/google/inject/internal/MissingImplementationError.java
+++ b/core/src/com/google/inject/internal/MissingImplementationError.java
@@ -55,7 +55,7 @@ public void formatDetail(List<ErrorDetail<?>> mergeableErrors, Formatter formatt
             .collect(Collectors.toList());
 
     if (!filteredSourcesList.isEmpty()) {
-      formatter.format("%n%s%n", Messages.bold("Requested by:"));
+      formatter.format("\n%s\n", Messages.bold("Requested by:"));
       int sourceListIndex = 1;
       for (List<Object> sources : filteredSourcesList) {
         ErrorFormatter.formatSources(sourceListIndex++, Lists.reverse(sources), formatter);
diff --git a/core/src/com/google/inject/internal/MissingImplementationErrorHints.java b/core/src/com/google/inject/internal/MissingImplementationErrorHints.java
index 9bcbe09568..a48ed5561d 100644
--- a/core/src/com/google/inject/internal/MissingImplementationErrorHints.java
+++ b/core/src/com/google/inject/internal/MissingImplementationErrorHints.java
@@ -49,20 +49,20 @@ static <T> ImmutableList<String> getSuggestions(Key<T> key, Injector injector) {
     List<String> possibleMatches = new ArrayList<>();
     List<Binding<T>> sameTypes = injector.findBindingsByType(type);
     if (!sameTypes.isEmpty()) {
-      suggestions.add("%nDid you mean?");
+      suggestions.add("\nDid you mean?");
       int howMany = min(sameTypes.size(), MAX_MATCHING_TYPES_REPORTED);
       for (int i = 0; i < howMany; ++i) {
         // TODO: Look into a better way to prioritize suggestions. For example, possbily
         // use levenshtein distance of the given annotation vs actual annotation.
-        suggestions.add(Messages.format("%n    * %s", sameTypes.get(i).getKey()));
+        suggestions.add(Messages.format("\n    * %s", sameTypes.get(i).getKey()));
       }
       int remaining = sameTypes.size() - MAX_MATCHING_TYPES_REPORTED;
       if (remaining > 0) {
         String plural = (remaining == 1) ? "" : "s";
         suggestions.add(
-            Messages.format("%n    %d more binding%s with other annotations.", remaining, plural));
+            Messages.format("\n    %d more binding%s with other annotations.", remaining, plural));
       }
-      suggestions.add("%n");
+      suggestions.add("\n");
     } else {
       // For now, do a simple substring search for possibilities. This can help spot
       // issues when there are generics being used (such as a wrapper class) and the
@@ -91,9 +91,9 @@ static <T> ImmutableList<String> getSuggestions(Key<T> key, Injector injector) {
       }
 
       if (!possibleMatches.isEmpty() && (possibleMatches.size() <= MAX_RELATED_TYPES_REPORTED)) {
-        suggestions.add("%nDid you mean?");
+        suggestions.add("\nDid you mean?");
         for (String possibleMatch : possibleMatches) {
-          suggestions.add(Messages.format("%n    %s", possibleMatch));
+          suggestions.add(Messages.format("\n    %s", possibleMatch));
         }
       }
     }
@@ -105,7 +105,7 @@ static <T> ImmutableList<String> getSuggestions(Key<T> key, Injector injector) {
         && key.getAnnotationType() == null
         && COMMON_AMBIGUOUS_TYPES.contains(key.getTypeLiteral().getRawType())) {
       // We don't recommend using such simple types without annotations.
-      suggestions.add("%nThe key seems very generic, did you forget an annotation?");
+      suggestions.add("\nThe key seems very generic, did you forget an annotation?");
     }
 
     return suggestions.build();
diff --git a/core/src/com/google/inject/internal/ProvisionListenerStackCallback.java b/core/src/com/google/inject/internal/ProvisionListenerStackCallback.java
index 45f8ec68c4..74fbeeaa13 100644
--- a/core/src/com/google/inject/internal/ProvisionListenerStackCallback.java
+++ b/core/src/com/google/inject/internal/ProvisionListenerStackCallback.java
@@ -76,7 +76,7 @@ public T provision(InternalContext context, ProvisionCallback<T> callable)
       throw InternalProvisionException.errorInUserCode(
           ErrorId.OTHER,
           caught,
-          "Error notifying ProvisionListener %s of %s.%n Reason: %s",
+          "Error notifying ProvisionListener %s of %s.\n Reason: %s",
           listener,
           binding.getKey(),
           caught);
diff --git a/core/src/com/google/inject/internal/RealMapBinder.java b/core/src/com/google/inject/internal/RealMapBinder.java
index 00b64d3608..bb7eb2d0cf 100644
--- a/core/src/com/google/inject/internal/RealMapBinder.java
+++ b/core/src/com/google/inject/internal/RealMapBinder.java
@@ -966,19 +966,19 @@ public List<Map.Entry<?, Binding<?>>> getEntries(Iterable<? extends Element> ele
 
         if (!keysOnlyFromBindings.isEmpty()) {
           sb.append(
-              Errors.format("%nFound these Bindings that were missing an associated entry:%n"));
+              Errors.format("\nFound these Bindings that were missing an associated entry:\n"));
           for (Key<V> key : keysOnlyFromBindings) {
             sb.append(
-                Errors.format("  %s bound at: %s%n", key, valueKeyToBinding.get(key).getSource()));
+                Errors.format("  %s bound at: %s\n", key, valueKeyToBinding.get(key).getSource()));
           }
         }
 
         if (!keysOnlyFromProviderMapEntrys.isEmpty()) {
-          sb.append(Errors.format("%nFound these map keys without a corresponding value:%n"));
+          sb.append(Errors.format("\nFound these map keys without a corresponding value:\n"));
           for (Key<V> key : keysOnlyFromProviderMapEntrys) {
             sb.append(
                 Errors.format(
-                    "  '%s' bound at: %s%n",
+                    "  '%s' bound at: %s\n",
                     valueKeyToKey.get(key), valueKeyToEntryBinding.get(key).getSource()));
           }
         }
diff --git a/core/src/com/google/inject/internal/ScopeNotFoundError.java b/core/src/com/google/inject/internal/ScopeNotFoundError.java
index f6f7e399f8..c3fa9baf4c 100644
--- a/core/src/com/google/inject/internal/ScopeNotFoundError.java
+++ b/core/src/com/google/inject/internal/ScopeNotFoundError.java
@@ -33,7 +33,7 @@ protected void formatDetail(List<ErrorDetail<?>> mergeableErrors, Formatter form
     sourcesSet.add(getSources());
     mergeableErrors.stream().map(ErrorDetail::getSources).forEach(sourcesSet::add);
 
-    formatter.format("%n%s%n", "Used at:");
+    formatter.format("\n%s\n", "Used at:");
     int sourceListIndex = 1;
     for (List<Object> sources : sourcesSet) {
       ErrorFormatter.formatSources(sourceListIndex++, Lists.reverse(sources), formatter);
diff --git a/core/src/com/google/inject/internal/SingletonScope.java b/core/src/com/google/inject/internal/SingletonScope.java
index 910d13b325..ffb2a87fbc 100644
--- a/core/src/com/google/inject/internal/SingletonScope.java
+++ b/core/src/com/google/inject/internal/SingletonScope.java
@@ -281,15 +281,15 @@ private Message createCycleDependenciesMessage(
         if (proxyCreationError != null) {
           fmt.format(" %s", proxyCreationError.getMessage());
         }
-        fmt.format("%n");
+        fmt.format("\n");
         for (Thread lockedThread : locksCycle.keySet()) {
           List<Key<?>> lockedKeys = locksCycle.get(lockedThread);
-          fmt.format("%s is holding locks the following singletons in the cycle:%n", lockedThread);
+          fmt.format("%s is holding locks the following singletons in the cycle:\n", lockedThread);
           for (Key<?> lockedKey : lockedKeys) {
-            fmt.format("%s%n", Errors.convert(lockedKey));
+            fmt.format("%s\n", Errors.convert(lockedKey));
           }
           for (StackTraceElement traceElement : lockedThread.getStackTrace()) {
-            fmt.format("\tat %s%n", traceElement);
+            fmt.format("\tat %s\n", traceElement);
           }
         }
         fmt.close();
diff --git a/core/src/com/google/inject/internal/SourceFormatter.java b/core/src/com/google/inject/internal/SourceFormatter.java
index 5492cc8a51..ae20220437 100644
--- a/core/src/com/google/inject/internal/SourceFormatter.java
+++ b/core/src/com/google/inject/internal/SourceFormatter.java
@@ -48,22 +48,22 @@ void format() {
     } else if (source instanceof InjectionPoint) {
       formatInjectionPoint(null, (InjectionPoint) source);
     } else if (source instanceof Class) {
-      formatter.format("%s%s%n", preposition("at "), StackTraceElements.forType((Class<?>) source));
+      formatter.format("%s%s\n", preposition("at "), StackTraceElements.forType((Class<?>) source));
     } else if (source instanceof Member) {
       formatMember((Member) source);
     } else if (source instanceof TypeLiteral) {
-      formatter.format("%s%s%n", preposition("while locating "), source);
+      formatter.format("%s%s\n", preposition("while locating "), source);
     } else if (source instanceof Key) {
       formatKey((Key<?>) source);
     } else if (source instanceof Thread) {
       appendModuleSource = false;
-      formatter.format("%s%s%n", preposition("in thread "), source);
+      formatter.format("%s%s\n", preposition("in thread "), source);
     } else {
-      formatter.format("%s%s%n", preposition("at "), source);
+      formatter.format("%s%s\n", preposition("at "), source);
     }
 
     if (appendModuleSource) {
-      formatter.format("%s \\_ installed by: %s%n", INDENT, moduleStack);
+      formatter.format("%s \\_ installed by: %s\n", INDENT, moduleStack);
     }
   }
 
@@ -84,11 +84,11 @@ private void formatDependency(Dependency<?> dependency) {
   }
 
   private void formatKey(Key<?> key) {
-    formatter.format("%s%s%n", preposition("while locating "), Messages.convert(key));
+    formatter.format("%s%s\n", preposition("while locating "), Messages.convert(key));
   }
 
   private void formatMember(Member member) {
-    formatter.format("%s%s%n", preposition("at "), StackTraceElements.forMember(member));
+    formatter.format("%s%s\n", preposition("at "), StackTraceElements.forMember(member));
   }
 
   private void formatInjectionPoint(Dependency<?> dependency, InjectionPoint injectionPoint) {
@@ -96,10 +96,10 @@ private void formatInjectionPoint(Dependency<?> dependency, InjectionPoint injec
     Class<? extends Member> memberType = Classes.memberType(member);
     formatMember(injectionPoint.getMember());
     if (memberType == Field.class) {
-      formatter.format("%s \\_ for field %s%n", INDENT, Messages.redBold(member.getName()));
+      formatter.format("%s \\_ for field %s\n", INDENT, Messages.redBold(member.getName()));
     } else if (dependency != null) {
 
-      formatter.format("%s \\_ for %s%n", INDENT, getParameterName(dependency));
+      formatter.format("%s \\_ for %s\n", INDENT, getParameterName(dependency));
     }
   }
 
diff --git a/core/src/com/google/inject/spi/BindingSourceRestriction.java b/core/src/com/google/inject/spi/BindingSourceRestriction.java
index 16dd62d6cb..58545c0ff8 100644
--- a/core/src/com/google/inject/spi/BindingSourceRestriction.java
+++ b/core/src/com/google/inject/spi/BindingSourceRestriction.java
@@ -69,7 +69,7 @@ public static Optional<String> getMissingImplementationSuggestion(
     }
     return Optional.of(
         String.format(
-            "%nHint: This key is restricted and cannot be bound directly. Restriction explanation:"
+            "\nHint: This key is restricted and cannot be bound directly. Restriction explanation:"
                 + " %s",
             restriction.explanation()));
   }
diff --git a/core/src/com/google/inject/spi/ErrorDetail.java b/core/src/com/google/inject/spi/ErrorDetail.java
index 677db1d5e7..ee732dc311 100644
--- a/core/src/com/google/inject/spi/ErrorDetail.java
+++ b/core/src/com/google/inject/spi/ErrorDetail.java
@@ -60,13 +60,13 @@ public boolean isMergeable(ErrorDetail<?> otherError) {
    */
   public final void format(int index, List<ErrorDetail<?>> mergeableErrors, Formatter formatter) {
     String id = getErrorIdentifier().map(s -> "[" + Messages.redBold(s) + "]: ").orElse("");
-    formatter.format("%s) %s%s%n", index, id, getMessage());
+    formatter.format("%s) %s%s\n", index, id, getMessage());
     formatDetail(mergeableErrors, formatter);
     // TODO(b/151482394): Output potiential fixes for the error
     Optional<String> learnMoreLink = getLearnMoreLink();
     if (learnMoreLink.isPresent()) {
-      formatter.format("%n%s%n", Messages.bold("Learn more:"));
-      formatter.format("  %s%n", Messages.underline(learnMoreLink.get()));
+      formatter.format("\n%s\n", Messages.bold("Learn more:"));
+      formatter.format("  %s\n", Messages.underline(learnMoreLink.get()));
     }
   }
 
diff --git a/core/src/com/google/inject/util/Modules.java b/core/src/com/google/inject/util/Modules.java
index 7818f0327a..4b5e9c9987 100644
--- a/core/src/com/google/inject/util/Modules.java
+++ b/core/src/com/google/inject/util/Modules.java
@@ -342,9 +342,9 @@ public Void visit(ScopeBinding scopeBinding) {
               StringBuilder sb =
                   new StringBuilder(
                       "The scope for @%s is bound directly and cannot be overridden.");
-              sb.append("%n     original binding at " + Errors.convert(scopeBinding.getSource()));
+              sb.append("\n     original binding at " + Errors.convert(scopeBinding.getSource()));
               for (Object usedSource : usedSources) {
-                sb.append("%n     bound directly at " + Errors.convert(usedSource) + "");
+                sb.append("\n     bound directly at " + Errors.convert(usedSource) + "");
               }
               binder
                   .withSource(overideBinding.getSource())
diff --git a/core/test/com/google/inject/BUILD b/core/test/com/google/inject/BUILD
index ac8fbb833e..d3893ffd6b 100644
--- a/core/test/com/google/inject/BUILD
+++ b/core/test/com/google/inject/BUILD
@@ -104,6 +104,25 @@ guice_test_suites(
     ],
 )
 
+guice_test_suites(
+    name = "gen_tests_with_windows_separator",
+    jvm_flags = [
+        # those 2 options are required for some tests that checks stack traces
+        "-XX:+UnlockDiagnosticVMOptions",
+        "-XX:+ShowHiddenFrames",
+        "-Dline.separator='\r\n'",
+    ],
+    sizes = [
+        "small",
+        "medium",
+    ],
+    suffix = "_with_windows_separator",
+    deps = [
+        ":add_opens_tests",
+        ":tests",
+    ],
+)
+
 [guice_test_suites(
     name = "gen_tests_stack_trace_%s" % include_stack_trace_option,
     args = [
diff --git a/core/test/com/google/inject/internal/MessagesTest.java b/core/test/com/google/inject/internal/MessagesTest.java
index ef959691a2..5568e882ee 100644
--- a/core/test/com/google/inject/internal/MessagesTest.java
+++ b/core/test/com/google/inject/internal/MessagesTest.java
@@ -23,7 +23,7 @@ static class ExampleErrorDetail extends ErrorDetail<ExampleErrorDetail> {
 
     @Override
     public void formatDetail(List<ErrorDetail<?>> mergeableErrors, Formatter formatter) {
-      formatter.format("Duplicate count: %s%n", mergeableErrors.size() + 1);
+      formatter.format("Duplicate count: %s\n", mergeableErrors.size() + 1);
     }
 
     @Override