add only modified for compiletest

4 files changed, 20 insertions, 16 deletions

diff --git a/src/bootstrap/builder/tests.rs b/src/bootstrap/builder/tests.rs
index d5fcd107502..3574f11189e 100644
--- a/src/bootstrap/builder/tests.rs
+++ b/src/bootstrap/builder/tests.rs
@@ -557,6 +557,7 @@ mod dist {
             rustfix_coverage: false,
             pass: None,
             run: None,
+            only_modified: false,
         };
 
         let build = Build::new(config);
@@ -627,6 +628,7 @@ mod dist {
             rustfix_coverage: false,
             pass: None,
             run: None,
+            only_modified: false,
         };
         // Make sure rustfmt binary not being found isn't an error.
         config.channel = "beta".to_string();
diff --git a/src/bootstrap/flags.rs b/src/bootstrap/flags.rs
index 52c3dc0bf75..ff927ed561b 100644
--- a/src/bootstrap/flags.rs
+++ b/src/bootstrap/flags.rs
@@ -124,6 +124,7 @@ pub enum Subcommand {
         fail_fast: bool,
         doc_tests: DocTests,
         rustfix_coverage: bool,
+        only_modified: bool,
     },
     Bench {
         paths: Vec<PathBuf>,
@@ -301,6 +302,7 @@ To learn more about a subcommand, run `./x.py <subcommand> -h`",
                 opts.optflag("", "doc", "only run doc tests");
                 opts.optflag("", "bless", "update all stderr/stdout files of failing ui tests");
                 opts.optflag("", "force-rerun", "rerun tests even if the inputs are unchanged");
+                opts.optflag("", "only-modified", "only run tests that result has been changed");
                 opts.optopt(
                     "",
                     "compare-mode",
@@ -598,6 +600,7 @@ Arguments:
                 rustc_args: matches.opt_strs("rustc-args"),
                 fail_fast: !matches.opt_present("no-fail-fast"),
                 rustfix_coverage: matches.opt_present("rustfix-coverage"),
+                only_modified: matches.opt_present("only-modified"),
                 doc_tests: if matches.opt_present("doc") {
                     DocTests::Only
                 } else if matches.opt_present("no-doc") {
@@ -777,6 +780,13 @@ impl Subcommand {
         }
     }
 
+    pub fn only_modified(&self) -> bool {
+        match *self {
+            Subcommand::Test { only_modified, .. } => only_modified,
+            _ => false,
+        }
+    }
+
     pub fn force_rerun(&self) -> bool {
         match *self {
             Subcommand::Test { force_rerun, .. } => force_rerun,
diff --git a/src/bootstrap/format.rs b/src/bootstrap/format.rs
index bfc57a85cdb..3166cabd131 100644
--- a/src/bootstrap/format.rs
+++ b/src/bootstrap/format.rs
@@ -1,8 +1,8 @@
 //! Runs rustfmt on the repository.
 
 use crate::builder::Builder;
-use crate::util::{output, output_result, program_out_of_date, t};
-use build_helper::git::updated_master_branch;
+use crate::util::{output, program_out_of_date, t};
+use build_helper::git::get_git_modified_files;
 use ignore::WalkBuilder;
 use std::collections::VecDeque;
 use std::path::{Path, PathBuf};
@@ -80,23 +80,11 @@ fn update_rustfmt_version(build: &Builder<'_>) {
 ///
 /// Returns `None` if all files should be formatted.
 fn get_modified_rs_files(build: &Builder<'_>) -> Result<Option<Vec<String>>, String> {
-    let Ok(updated_master) = updated_master_branch(Some(&build.config.src)) else { return Ok(None); };
-
     if !verify_rustfmt_version(build) {
         return Ok(None);
     }
 
-    let merge_base =
-        output_result(build.config.git().arg("merge-base").arg(&updated_master).arg("HEAD"))?;
-    Ok(Some(
-        output_result(
-            build.config.git().arg("diff-index").arg("--name-only").arg(merge_base.trim()),
-        )?
-        .lines()
-        .map(|s| s.trim().to_owned())
-        .filter(|f| Path::new(f).extension().map_or(false, |ext| ext == "rs"))
-        .collect(),
-    ))
+    get_git_modified_files(Some(&build.config.src), &vec!["rs"])
 }
 
 #[derive(serde::Deserialize)]
@@ -169,7 +157,7 @@ pub fn format(build: &Builder<'_>, check: bool, paths: &[PathBuf]) {
                 ignore_fmt.add(&format!("!/{}", untracked_path)).expect(&untracked_path);
             }
             if !check && paths.is_empty() {
-                match get_modified_rs_files(build) {
+                match get_modified_rs_files(&build) {
                     Ok(Some(files)) => {
                         for file in files {
                             println!("formatting modified file {file}");
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index 6078e39ac9d..30380da7ba2 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -1508,6 +1508,10 @@ note: if you're sure you want to do this, please open an issue as to why. In the
         if builder.config.rust_optimize_tests {
             cmd.arg("--optimize-tests");
         }
+        if builder.config.cmd.only_modified() {
+            cmd.arg("--only-modified");
+        }
+
         let mut flags = if is_rustdoc { Vec::new() } else { vec!["-Crpath".to_string()] };
         flags.push(format!("-Cdebuginfo={}", builder.config.rust_debuginfo_level_tests));
         flags.extend(builder.config.cmd.rustc_args().iter().map(|s| s.to_string()));