diff --git a/.github/workflows/post-merge.yml b/.github/workflows/post-merge.yml
index d38cc0e8a17f..51e0a40d46f2 100644
--- a/.github/workflows/post-merge.yml
+++ b/.github/workflows/post-merge.yml
@@ -29,7 +29,7 @@ jobs:
           sleep 60
 
           # Get closest bors merge commit
-          PARENT_COMMIT=`git rev-list --author='bors <bors@rust-lang.org>' -n1 --first-parent HEAD^1`
+          PARENT_COMMIT=`git rev-list --author='122020455+rust-bors\[bot\]@users.noreply.github.com' -n1 --first-parent HEAD^1`
           echo "Parent: ${PARENT_COMMIT}"
 
           # Find PR for the current commit
diff --git a/src/build_helper/src/git.rs b/src/build_helper/src/git.rs
index 42d9b00f004a..1fdc2ddb4cfc 100644
--- a/src/build_helper/src/git.rs
+++ b/src/build_helper/src/git.rs
@@ -152,6 +152,14 @@ pub fn has_changed_since(git_dir: &Path, base: &str, paths: &[&str]) -> bool {
     })
 }
 
+const LEGACY_BORS_EMAIL: &str = "bors@rust-lang.org";
+
+/// Escape characters from the git user e-mail, so that git commands do not interpret it as regex
+/// special characters.
+fn escape_email_git_regex(text: &str) -> String {
+    text.replace("[", "\\[").replace("]", "\\]").replace(".", "\\.")
+}
+
 /// Returns the latest upstream commit that modified `target_paths`, or `None` if no such commit
 /// was found.
 fn get_latest_upstream_commit_that_modified_files(
@@ -182,9 +190,15 @@ fn get_latest_upstream_commit_that_modified_files(
         "-n1",
         &upstream,
         "--author",
-        git_config.git_merge_commit_email,
+        &escape_email_git_regex(git_config.git_merge_commit_email),
     ]);
 
+    // Also search for legacy bors account, before we accrue enough commits to
+    // have changes to all relevant file paths done by new bors.
+    if git_config.git_merge_commit_email != LEGACY_BORS_EMAIL {
+        git.args(["--author", LEGACY_BORS_EMAIL]);
+    }
+
     if !target_paths.is_empty() {
         git.arg("--").args(target_paths);
     }
@@ -229,11 +243,17 @@ pub fn get_closest_upstream_commit(
     git.args([
         "rev-list",
         "--author-date-order",
-        &format!("--author={}", config.git_merge_commit_email),
+        &format!("--author={}", &escape_email_git_regex(config.git_merge_commit_email),),
         "-n1",
         base,
     ]);
 
+    // Also search for legacy bors account, before we accrue enough commits to
+    // have changes to all relevant file paths done by new bors.
+    if config.git_merge_commit_email != LEGACY_BORS_EMAIL {
+        git.args(["--author", LEGACY_BORS_EMAIL]);
+    }
+
     let output = output_result(&mut git)?.trim().to_owned();
     if output.is_empty() { Ok(None) } else { Ok(Some(output)) }
 }
diff --git a/src/ci/docker/run.sh b/src/ci/docker/run.sh
index 044f5a8fff32..691b8b8deb81 100755
--- a/src/ci/docker/run.sh
+++ b/src/ci/docker/run.sh
@@ -312,16 +312,6 @@ else
   command=(/checkout/src/ci/run.sh)
 fi
 
-if isCI; then
-  # Get some needed information for $BASE_COMMIT
-  #
-  # This command gets the last merge commit which we'll use as base to list
-  # deleted files since then.
-  BASE_COMMIT="$(git log --author=bors@rust-lang.org -n 2 --pretty=format:%H | tail -n 1)"
-else
-  BASE_COMMIT=""
-fi
-
 SUMMARY_FILE=github-summary.md
 touch $objdir/${SUMMARY_FILE}
 
@@ -359,7 +349,6 @@ docker \
   --env RUST_CI_OVERRIDE_RELEASE_CHANNEL \
   --env CI_JOB_NAME="${CI_JOB_NAME-$image}" \
   --env CI_JOB_DOC_URL="${CI_JOB_DOC_URL}" \
-  --env BASE_COMMIT="$BASE_COMMIT" \
   --env DIST_TRY_BUILD \
   --env PR_CI_JOB \
   --env OBJDIR_ON_HOST="$objdir" \
diff --git a/src/stage0 b/src/stage0
index 66b652a844f3..226f1d6f645e 100644
--- a/src/stage0
+++ b/src/stage0
@@ -1,7 +1,7 @@
 dist_server=https://static.rust-lang.org
 artifacts_server=https://ci-artifacts.rust-lang.org/rustc-builds
 artifacts_with_llvm_assertions_server=https://ci-artifacts.rust-lang.org/rustc-builds-alt
-git_merge_commit_email=bors@rust-lang.org
+git_merge_commit_email=122020455+rust-bors[bot]@users.noreply.github.com
 nightly_branch=main
 
 # The configuration above this comment is editable, and can be changed