From 2f6958666779177f1c1264258a9e0ef309afeaac Mon Sep 17 00:00:00 2001
From: Peter Van der Beken <peterv@propagandism.org>
Date: Sun, 11 Oct 2020 19:26:51 +0000
Subject: [PATCH] Bug 1668940 - Tabs that crash in the background fail to
 restore with SHIP. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D92662
---
 docshell/base/nsDocShell.cpp | 25 +++++++++++++------------
 docshell/base/nsDocShell.h   |  2 +-
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index d2920f05f86e..17fa0b869de3 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -3987,13 +3987,6 @@ nsresult nsDocShell::LoadErrorPage(nsIURI* aErrorURI, nsIURI* aFailedURI,
     // identifier, the error page won't persist.
     mLSHE->AbandonBFCacheEntry();
   }
-  if (mozilla::SessionHistoryInParent()) {
-    // Commit the loading entry for the real load here, Embed will not commit
-    // the loading entry for the error page. History will then contain an entry
-    // for the real load, and the error page won't persist if we try loading
-    // that entry again.
-    MoveLoadingToActiveEntry(true);
-  }
 
   RefPtr<nsDocShellLoadState> loadState = new nsDocShellLoadState(aErrorURI);
   loadState->SetTriggeringPrincipal(nsContentUtils::GetSystemPrincipal());
@@ -4003,6 +3996,12 @@ nsresult nsDocShell::LoadErrorPage(nsIURI* aErrorURI, nsIURI* aFailedURI,
   loadState->SetLoadType(LOAD_ERROR_PAGE);
   loadState->SetFirstParty(true);
   loadState->SetSourceBrowsingContext(mBrowsingContext);
+  if (mozilla::SessionHistoryInParent() && mLoadingEntry) {
+    // We keep the loading entry for the load that failed here. If the user
+    // reloads we want to try to reload the original load, not the error page.
+    loadState->SetLoadingSessionHistoryInfo(
+        MakeUnique<LoadingSessionHistoryInfo>(*mLoadingEntry));
+  }
   return InternalLoad(loadState);
 }
 
@@ -5705,7 +5704,7 @@ nsresult nsDocShell::Embed(nsIContentViewer* aContentViewer,
 
   if (!aIsTransientAboutBlank && mozilla::SessionHistoryInParent()) {
     MOZ_LOG(gSHLog, LogLevel::Debug, ("document %p Embed", this));
-    MoveLoadingToActiveEntry(mLoadType != LOAD_ERROR_PAGE);
+    MoveLoadingToActiveEntry();
   }
 
   bool updateHistory = true;
@@ -13242,7 +13241,7 @@ void nsDocShell::SetLoadingSessionHistoryInfo(
   mLoadingEntry = MakeUnique<LoadingSessionHistoryInfo>(aLoadingInfo);
 }
 
-void nsDocShell::MoveLoadingToActiveEntry(bool aCommit) {
+void nsDocShell::MoveLoadingToActiveEntry() {
   MOZ_ASSERT(mozilla::SessionHistoryInParent());
 
   MOZ_LOG(gSHLog, LogLevel::Debug,
@@ -13261,12 +13260,14 @@ void nsDocShell::MoveLoadingToActiveEntry(bool aCommit) {
     mLoadingEntry.swap(loadingEntry);
   }
 
-  if (mActiveEntry && aCommit) {
+  if (mActiveEntry) {
     MOZ_ASSERT(loadingEntry);
     nsID changeID = {};
+    uint32_t loadType =
+        mLoadType == LOAD_ERROR_PAGE ? mFailedLoadType : mLoadType;
     if (XRE_IsParentProcess()) {
       mBrowsingContext->Canonical()->SessionHistoryCommit(loadingEntry->mLoadId,
-                                                          changeID, mLoadType);
+                                                          changeID, loadType);
     } else {
       RefPtr<ChildSHistory> rootSH = GetRootSessionHistory();
       if (rootSH) {
@@ -13282,7 +13283,7 @@ void nsDocShell::MoveLoadingToActiveEntry(bool aCommit) {
       }
       ContentChild* cc = ContentChild::GetSingleton();
       mozilla::Unused << cc->SendHistoryCommit(
-          mBrowsingContext, loadingEntry->mLoadId, changeID, mLoadType);
+          mBrowsingContext, loadingEntry->mLoadId, changeID, loadType);
     }
   }
 }
diff --git a/docshell/base/nsDocShell.h b/docshell/base/nsDocShell.h
index 2316f5645482..02b8bc9745f9 100644
--- a/docshell/base/nsDocShell.h
+++ b/docshell/base/nsDocShell.h
@@ -1104,7 +1104,7 @@ class nsDocShell final : public nsDocLoader,
   // Sets the active entry to the current loading entry. If aCommit is true then
   // SessionHistoryCommit will be called on the CanonicalBrowsingContext
   // (directly or over IPC).
-  void MoveLoadingToActiveEntry(bool aCommit);
+  void MoveLoadingToActiveEntry();
 
  private:  // data members
   nsString mTitle;