allow multiple fallbacks for --affected base branch (#9045)

### Description

We use `main` as our default for base branch, but a lot of repos are
likely using `master`, we should fall back to that if `main` isn't a
valid ref.

### Testing Instructions

see unit tests
https://github.com/vercel/turborepo/pull/9045/files#diff-db1296fb6f1a06e197e7cd6cdf5979b738c6b56b7700b048ab3b00fd767f8aecR734-R746
for situations to test manually.

---------

Co-authored-by: Chris Olszewski <chris.olszewski@vercel.com>

crates/turborepo-lib/src/commands/config.rs

@@ -23,7 +23,7 @@ struct ConfigOutput<'a> {
     package_manager: PackageManager,
     daemon: Option<bool>,
     env_mode: EnvMode,
-    scm_base: &'a str,
+    scm_base: Option<&'a str>,
     scm_head: &'a str,
     cache_dir: &'a Utf8Path,
 }

crates/turborepo-lib/src/config.rs

@@ -298,8 +298,8 @@ impl ConfigurationOptions {
         self.ui.unwrap_or(UIMode::Stream)
     }
 
-    pub fn scm_base(&self) -> &str {
-        self.scm_base.as_deref().unwrap_or("main")
+    pub fn scm_base(&self) -> Option<&str> {
+        self.scm_base.as_deref()
     }
 
     pub fn scm_head(&self) -> &str {

crates/turborepo-lib/src/opts.rs

@@ -307,7 +307,7 @@ pub struct ScopeOpts {
     pub pkg_inference_root: Option<AnchoredSystemPathBuf>,
     pub global_deps: Vec<String>,
     pub filter_patterns: Vec<String>,
-    pub affected_range: Option<(String, String)>,
+    pub affected_range: Option<(Option<String>, String)>,
 }
 
 impl<'a> TryFrom<OptsInputs<'a>> for ScopeOpts {
@@ -324,7 +324,7 @@ impl<'a> TryFrom<OptsInputs<'a>> for ScopeOpts {
         let affected_range = inputs.execution_args.affected.then(|| {
             let scm_base = inputs.config.scm_base();
             let scm_head = inputs.config.scm_head();
-            (scm_base.to_string(), scm_head.to_string())
+            (scm_base.map(|b| b.to_owned()), scm_head.to_string())
         });
 
         Ok(Self {
@@ -513,7 +513,7 @@ mod test {
             pkg_inference_root: None,
             global_deps: vec![],
             filter_patterns: opts_input.filter_patterns,
-            affected_range: opts_input.affected,
+            affected_range: opts_input.affected.map(|(base, head)| (Some(base), head)),
         };
         let opts = Opts {
             run_opts,

crates/turborepo-lib/src/query.rs

@@ -242,7 +242,7 @@ impl Query {
         base: Option<String>,
         head: Option<String>,
     ) -> Result<Vec<Package>, Error> {
-        let base = base.unwrap_or_else(|| "main".to_string());
+        let base = base.map(|s| s.to_owned());
         let head = head.unwrap_or_else(|| "HEAD".to_string());
         let mut opts = self.run.opts().clone();
         opts.scope_opts.affected_range = Some((base, head));

crates/turborepo-lib/src/run/scope/change_detector.rs

@@ -17,7 +17,7 @@ use crate::{
 pub trait GitChangeDetector {
     fn changed_packages(
         &self,
-        from_ref: &str,
+        from_ref: Option<&str>,
         to_ref: Option<&str>,
         include_uncommitted: bool,
         allow_unknown_objects: bool,
@@ -55,7 +55,7 @@ impl<'a> ScopeChangeDetector<'a> {
     /// returns an empty lockfile change
     fn get_lockfile_contents(
         &self,
-        from_ref: &str,
+        from_ref: Option<&str>,
         changed_files: &HashSet<AnchoredSystemPathBuf>,
     ) -> Option<LockfileChange> {
         let lockfile_path = self
@@ -88,13 +88,13 @@ impl<'a> ScopeChangeDetector<'a> {
 impl<'a> GitChangeDetector for ScopeChangeDetector<'a> {
     fn changed_packages(
         &self,
-        from_ref: &str,
+        from_ref: Option<&str>,
         to_ref: Option<&str>,
         include_uncommitted: bool,
         allow_unknown_objects: bool,
     ) -> Result<HashSet<PackageName>, ResolutionError> {
         let mut changed_files = HashSet::new();
-        if !from_ref.is_empty() {
+        if !from_ref.map_or(false, |s| s.is_empty()) {
             changed_files = match self.scm.changed_files(
                 self.turbo_root,
                 from_ref,

crates/turborepo-lib/src/run/scope/filter.rs

@@ -163,7 +163,7 @@ impl<'a, T: GitChangeDetector> FilterResolver<'a, T> {
     /// It applies the following rules:
     pub(crate) fn resolve(
         &self,
-        affected: &Option<(String, String)>,
+        affected: &Option<(Option<String>, String)>,
         patterns: &[String],
     ) -> Result<(HashSet<PackageName>, bool), ResolutionError> {
         // inference is None only if we are in the root
@@ -185,7 +185,7 @@ impl<'a, T: GitChangeDetector> FilterResolver<'a, T> {
 
     fn get_packages_from_patterns(
         &self,
-        affected: &Option<(String, String)>,
+        affected: &Option<(Option<String>, String)>,
         patterns: &[String],
     ) -> Result<HashSet<PackageName>, ResolutionError> {
         let mut selectors = patterns
@@ -196,7 +196,7 @@ impl<'a, T: GitChangeDetector> FilterResolver<'a, T> {
         if let Some((from_ref, to_ref)) = affected {
             selectors.push(TargetSelector {
                 git_range: Some(GitRange {
-                    from_ref: from_ref.to_string(),
+                    from_ref: from_ref.clone(),
                     to_ref: Some(to_ref.to_string()),
                     include_uncommitted: true,
                     allow_unknown_objects: true,
@@ -549,7 +549,7 @@ impl<'a, T: GitChangeDetector> FilterResolver<'a, T> {
         git_range: &GitRange,
     ) -> Result<HashSet<PackageName>, ResolutionError> {
         self.change_detector.changed_packages(
-            &git_range.from_ref,
+            git_range.from_ref.as_deref(),
             git_range.to_ref.as_deref(),
             git_range.include_uncommitted,
             git_range.allow_unknown_objects,
@@ -1123,7 +1123,7 @@ mod test {
     #[test_case(
         vec![
             TargetSelector {
-                git_range: Some(GitRange { from_ref: "HEAD~1".to_string(), to_ref: None, ..Default::default() }),
+                git_range: Some(GitRange { from_ref: Some("HEAD~1".to_string()), to_ref: None, ..Default::default() }),
                 ..Default::default()
             }
         ],
@@ -1133,7 +1133,7 @@ mod test {
     #[test_case(
         vec![
             TargetSelector {
-                git_range: Some(GitRange { from_ref: "HEAD~1".to_string(), to_ref: None, ..Default::default() }),
+                git_range: Some(GitRange { from_ref: Some("HEAD~1".to_string()), to_ref: None, ..Default::default() }),
                 parent_dir: Some(AnchoredSystemPathBuf::try_from(".").unwrap()),
                 ..Default::default()
             }
@@ -1144,7 +1144,7 @@ mod test {
     #[test_case(
         vec![
             TargetSelector {
-                git_range: Some(GitRange { from_ref: "HEAD~1".to_string(), to_ref: None, ..Default::default() }),
+                git_range: Some(GitRange { from_ref: Some("HEAD~1".to_string()), to_ref: None, ..Default::default() }),
                 parent_dir: Some(AnchoredSystemPathBuf::try_from("package-2").unwrap()),
                 ..Default::default()
             }
@@ -1155,7 +1155,7 @@ mod test {
     #[test_case(
         vec![
             TargetSelector {
-                git_range: Some(GitRange { from_ref: "HEAD~1".to_string(), to_ref: None, ..Default::default() }),
+                git_range: Some(GitRange { from_ref: Some("HEAD~1".to_string()), to_ref: None, ..Default::default() }),
                 name_pattern: "package-2*".to_string(),
                 ..Default::default()
             }
@@ -1166,7 +1166,7 @@ mod test {
     #[test_case(
         vec![
             TargetSelector {
-                git_range: Some(GitRange { from_ref: "HEAD~1".to_string(), to_ref: None, ..Default::default() }),
+                git_range: Some(GitRange { from_ref: Some("HEAD~1".to_string()), to_ref: None, ..Default::default() }),
                 name_pattern: "package-1".to_string(),
                 match_dependencies: true,
                 ..Default::default()
@@ -1178,7 +1178,7 @@ mod test {
     #[test_case(
         vec![
             TargetSelector {
-                git_range: Some(GitRange { from_ref: "HEAD~2".to_string(), to_ref: None, ..Default::default() }),
+                git_range: Some(GitRange { from_ref: Some("HEAD~2".to_string()), to_ref: None, ..Default::default() }),
                 ..Default::default()
             }
         ],
@@ -1188,7 +1188,7 @@ mod test {
     #[test_case(
         vec![
             TargetSelector {
-                git_range: Some(GitRange { from_ref: "HEAD~2".to_string(), to_ref: Some("HEAD~1".to_string()), ..Default::default() }),
+                git_range: Some(GitRange { from_ref: Some("HEAD~2".to_string()), to_ref: Some("HEAD~1".to_string()), ..Default::default() }),
                 ..Default::default()
             }
         ],
@@ -1198,7 +1198,7 @@ mod test {
     #[test_case(
         vec![
             TargetSelector {
-                git_range: Some(GitRange { from_ref: "HEAD~1".to_string(), to_ref: None, ..Default::default() }),
+                git_range: Some(GitRange { from_ref: Some("HEAD~1".to_string()), to_ref: None, ..Default::default() }),
                 parent_dir: Some(AnchoredSystemPathBuf::try_from("package-*").unwrap()),
                 match_dependencies: true,             ..Default::default()
             }
@@ -1250,14 +1250,14 @@ mod test {
     impl<'a> GitChangeDetector for TestChangeDetector<'a> {
         fn changed_packages(
             &self,
-            from: &str,
+            from: Option<&str>,
             to: Option<&str>,
             _include_uncommitted: bool,
             _allow_unknown_objects: bool,
         ) -> Result<HashSet<PackageName>, ResolutionError> {
             Ok(self
                 .0
-                .get(&(from, to))
+                .get(&(from.expect("expected base branch"), to))
                 .map(|h| h.to_owned())
                 .expect("unsupported range"))
         }

crates/turborepo-lib/src/run/scope/target_selector.rs

@@ -6,7 +6,7 @@ use turbopath::AnchoredSystemPathBuf;
 
 #[derive(Debug, Default, PartialEq)]
 pub struct GitRange {
-    pub from_ref: String,
+    pub from_ref: Option<String>,
     pub to_ref: Option<String>,
     pub include_uncommitted: bool,
     // Allow unknown objects to be included in the range, without returning an error.
@@ -155,7 +155,7 @@ impl FromStr for TargetSelector {
                     ));
                 }
                 GitRange {
-                    from_ref: a.to_string(),
+                    from_ref: Some(a.to_string()),
                     to_ref: Some(b.to_string()),
                     include_uncommitted: false,
                     allow_unknown_objects: false,
@@ -164,7 +164,7 @@ impl FromStr for TargetSelector {
                 // If only the start of the range is specified, we assume that
                 // we want to include uncommitted changes
                 GitRange {
-                    from_ref: commits_str.to_string(),
+                    from_ref: Some(commits_str.to_string()),
                     to_ref: None,
                     include_uncommitted: true,
                     allow_unknown_objects: false,
@@ -252,17 +252,17 @@ mod test {
     #[test_case("...{./foo}", TargetSelector { raw: "...{./foo}".to_string(), parent_dir: Some(AnchoredSystemPathBuf::try_from("foo").unwrap()), include_dependents: true, ..Default::default() }; "dot dot dot curly bracket foo")]
     #[test_case(".", TargetSelector { raw: ".".to_string(), parent_dir: Some(AnchoredSystemPathBuf::try_from(".").unwrap()), ..Default::default() }; "parent dir dot")]
     #[test_case("..", TargetSelector { raw: "..".to_string(), parent_dir: Some(AnchoredSystemPathBuf::try_from("..").unwrap()), ..Default::default() }; "parent dir dot dot")]
-    #[test_case("[master]", TargetSelector { raw: "[master]".to_string(), git_range: Some(GitRange { from_ref: "master".to_string(), to_ref: None, include_uncommitted: true, ..Default::default() }), ..Default::default() }; "square brackets master")]
-    #[test_case("[from...to]", TargetSelector { raw: "[from...to]".to_string(), git_range: Some(GitRange { from_ref: "from".to_string(), to_ref: Some("to".to_string()), ..Default::default() }), ..Default::default() }; "[from...to]")]
-    #[test_case("{foo}[master]", TargetSelector { raw: "{foo}[master]".to_string(), git_range: Some(GitRange { from_ref: "master".to_string(), to_ref: None, include_uncommitted: true, ..Default::default() }), parent_dir: Some(AnchoredSystemPathBuf::try_from("foo").unwrap()), ..Default::default() }; "{foo}[master]")]
-    #[test_case("pattern{foo}[master]", TargetSelector { raw: "pattern{foo}[master]".to_string(), git_range: Some(GitRange { from_ref: "master".to_string(), to_ref: None, include_uncommitted: true, ..Default::default() }), parent_dir: Some(AnchoredSystemPathBuf::try_from("foo").unwrap()), name_pattern: "pattern".to_string(), ..Default::default() }; "pattern{foo}[master]")]
-    #[test_case("[master]...", TargetSelector { raw: "[master]...".to_string(), git_range: Some(GitRange { from_ref: "master".to_string(), to_ref: None, include_uncommitted: true, ..Default::default() }), include_dependencies: true, ..Default::default() }; "square brackets master dot dot dot")]
-    #[test_case("...[master]", TargetSelector { raw: "...[master]".to_string(), git_range: Some(GitRange { from_ref: "master".to_string(), to_ref: None, include_uncommitted: true, ..Default::default() }), include_dependents: true, ..Default::default() }; "dot dot dot master square brackets")]
-    #[test_case("...[master]...", TargetSelector { raw: "...[master]...".to_string(), git_range: Some(GitRange { from_ref: "master".to_string(), to_ref: None, include_uncommitted: true, ..Default::default() }), include_dependencies: true, include_dependents: true, ..Default::default() }; "dot dot dot master square brackets dot dot dot")]
-    #[test_case("...[from...to]...", TargetSelector { raw: "...[from...to]...".to_string(), git_range: Some(GitRange { from_ref: "from".to_string(), to_ref: Some("to".to_string()), ..Default::default() }), include_dependencies: true, include_dependents: true, ..Default::default() }; "dot dot dot [from...to] dot dot dot")]
-    #[test_case("foo...[master]", TargetSelector { raw: "foo...[master]".to_string(), git_range: Some(GitRange { from_ref: "master".to_string(), to_ref: None, include_uncommitted: true, ..Default::default() }), name_pattern: "foo".to_string(), match_dependencies: true, ..Default::default() }; "foo...[master]")]
-    #[test_case("foo...[master]...", TargetSelector { raw: "foo...[master]...".to_string(), git_range: Some(GitRange { from_ref: "master".to_string(), to_ref: None, include_uncommitted: true, ..Default::default() }), name_pattern: "foo".to_string(), match_dependencies: true, include_dependencies: true, ..Default::default() }; "foo...[master] dot dot dot")]
-    #[test_case("{foo}...[master]", TargetSelector { raw: "{foo}...[master]".to_string(), git_range: Some(GitRange { from_ref: "master".to_string(), to_ref: None, include_uncommitted: true, ..Default::default() }), parent_dir: Some(AnchoredSystemPathBuf::try_from("foo").unwrap()), match_dependencies: true, ..Default::default() }; " curly brackets foo...[master]")]
+    #[test_case("[master]", TargetSelector { raw: "[master]".to_string(), git_range: Some(GitRange { from_ref: Some("master".to_string()), to_ref: None, include_uncommitted: true, ..Default::default() }), ..Default::default() }; "square brackets master")]
+    #[test_case("[from...to]", TargetSelector { raw: "[from...to]".to_string(), git_range: Some(GitRange { from_ref: Some("from".to_string()), to_ref: Some("to".to_string()), ..Default::default() }), ..Default::default() }; "[from...to]")]
+    #[test_case("{foo}[master]", TargetSelector { raw: "{foo}[master]".to_string(), git_range: Some(GitRange { from_ref: Some("master".to_string()), to_ref: None, include_uncommitted: true, ..Default::default() }), parent_dir: Some(AnchoredSystemPathBuf::try_from("foo").unwrap()), ..Default::default() }; "{foo}[master]")]
+    #[test_case("pattern{foo}[master]", TargetSelector { raw: "pattern{foo}[master]".to_string(), git_range: Some(GitRange { from_ref: Some("master".to_string()), to_ref: None, include_uncommitted: true, ..Default::default() }), parent_dir: Some(AnchoredSystemPathBuf::try_from("foo").unwrap()), name_pattern: "pattern".to_string(), ..Default::default() }; "pattern{foo}[master]")]
+    #[test_case("[master]...", TargetSelector { raw: "[master]...".to_string(), git_range: Some(GitRange { from_ref: Some("master".to_string()), to_ref: None, include_uncommitted: true, ..Default::default() }), include_dependencies: true, ..Default::default() }; "square brackets master dot dot dot")]
+    #[test_case("...[master]", TargetSelector { raw: "...[master]".to_string(), git_range: Some(GitRange { from_ref: Some("master".to_string()), to_ref: None, include_uncommitted: true, ..Default::default() }), include_dependents: true, ..Default::default() }; "dot dot dot master square brackets")]
+    #[test_case("...[master]...", TargetSelector { raw: "...[master]...".to_string(), git_range: Some(GitRange { from_ref: Some("master".to_string()), to_ref: None, include_uncommitted: true, ..Default::default() }), include_dependencies: true, include_dependents: true, ..Default::default() }; "dot dot dot master square brackets dot dot dot")]
+    #[test_case("...[from...to]...", TargetSelector { raw: "...[from...to]...".to_string(), git_range: Some(GitRange { from_ref: Some("from".to_string()), to_ref: Some("to".to_string()), ..Default::default() }), include_dependencies: true, include_dependents: true, ..Default::default() }; "dot dot dot [from...to] dot dot dot")]
+    #[test_case("foo...[master]", TargetSelector { raw: "foo...[master]".to_string(), git_range: Some(GitRange { from_ref: Some("master".to_string()), to_ref: None, include_uncommitted: true, ..Default::default() }), name_pattern: "foo".to_string(), match_dependencies: true, ..Default::default() }; "foo...[master]")]
+    #[test_case("foo...[master]...", TargetSelector { raw: "foo...[master]...".to_string(), git_range: Some(GitRange { from_ref: Some("master".to_string()), to_ref: None, include_uncommitted: true, ..Default::default() }), name_pattern: "foo".to_string(), match_dependencies: true, include_dependencies: true, ..Default::default() }; "foo...[master] dot dot dot")]
+    #[test_case("{foo}...[master]", TargetSelector { raw: "{foo}...[master]".to_string(), git_range: Some(GitRange { from_ref: Some("master".to_string()), to_ref: None, include_uncommitted: true, ..Default::default() }), parent_dir: Some(AnchoredSystemPathBuf::try_from("foo").unwrap()), match_dependencies: true, ..Default::default() }; " curly brackets foo...[master]")]
     fn parse_target_selector(raw_selector: &str, want: TargetSelector) {
         let result = TargetSelector::from_str(raw_selector);