commenter disabled: count transitive dependents

CURATORS.md

@@ -533,6 +533,20 @@ TARGET=nightly-2021-01-14 \ # the date doesn't matter
   curator snapshot
 ```
 
+#### Finding disabled packages with lots of dependents
+
+`commenter disabled` prints the number of transitive dependents a disabled package has. Low hanging fruit to get a lot of packages included again.
+
+Example output:
+```
+[...]
+stringable is disabled with 10 dependents
+llvm-hs is disabled with 12 dependents
+th-data-compat is disabled with 12 dependents
+amazonka-core is disabled with 96 dependents
+gogol-core is disabled with 96 dependents
+```
+
 ## Adding new curators
 
 1. Add public ssh key to `~/.ssh/authorized_keys` on build server

etc/commenter/src/lib.rs

@@ -188,6 +188,7 @@ enum State {
     Done,
 }
 
+#[derive(PartialEq, Eq, Debug)]
 struct VersionedPackage {
     package: Package,
     version: Version,
@@ -352,7 +353,7 @@ struct SnapshotPackage {
     // pantry-tree
 }
 
-#[derive(PartialOrd, Ord, PartialEq, Eq, Clone)]
+#[derive(PartialOrd, Ord, PartialEq, Eq, Clone, Debug)]
 struct Package(String);
 
 impl fmt::Display for Package {
@@ -361,7 +362,7 @@ impl fmt::Display for Package {
     }
 }
 
-#[derive(Clone, PartialOrd, Ord, PartialEq, Eq)]
+#[derive(Clone, PartialOrd, Ord, PartialEq, Eq, Debug)]
 struct Version(String);
 
 impl fmt::Display for Version {
@@ -457,3 +458,117 @@ pub fn diff_snapshot(a: String, b: String) {
         println!("{s}");
     }
 }
+
+#[derive(PartialEq, Eq, Debug)]
+struct DisabledTransitively {
+    child: VersionedPackage,
+    parent: Package,
+}
+
+fn parse_disabled_transitviely(s: &str) -> Option<DisabledTransitively> {
+    let r = regex!(
+        r#"- *([^ ]+) < *0 *# tried [^ ]+-([\d.]+), but its \*[^*]+\* requires the disabled package: ([^ ]+)"#
+    );
+    if let Some(caps) = r.captures(s) {
+        let package = Package(caps.get(1).unwrap().as_str().to_owned());
+        let version = Version(caps.get(2).unwrap().as_str().to_owned());
+        let parent = Package(caps.get(3).unwrap().as_str().to_owned());
+        Some(DisabledTransitively {
+            child: VersionedPackage { package, version },
+            parent,
+        })
+    } else {
+        None
+    }
+}
+
+#[test]
+fn test_parse_disabled_transitviely() {
+    let s = "- Network-NineP < 0 # tried Network-NineP-0.4.7.1, but its *library* requires the disabled package: mstate";
+    assert_eq!(
+        parse_disabled_transitviely(s),
+        Some(DisabledTransitively {
+            child: VersionedPackage {
+                package: Package("Network-NineP".to_owned()),
+                version: Version("0.4.7.1".to_owned())
+            },
+            parent: Package("mstate".to_owned()),
+        })
+    )
+}
+
+type M = BTreeMap<Package, (Vec<VersionedPackage>, Option<usize>)>;
+
+pub fn disabled() {
+    let mut disabled_transitively: Vec<DisabledTransitively> = vec![];
+    handle(false, |loc, lines| {
+        match loc {
+            Location::Lib => disabled_transitively.extend(
+                lines
+                    .into_iter()
+                    .map(|line| parse_disabled_transitviely(&line))
+                    .flatten()
+                    .collect::<Vec<_>>(),
+            ),
+            Location::Test | Location::Bench => (),
+        }
+        vec![]
+    });
+
+    let mut packages: BTreeSet<Package> = BTreeSet::new();
+    let mut disabled: M = BTreeMap::new();
+
+    for DisabledTransitively { child, parent } in disabled_transitively {
+        packages.insert(child.package.clone());
+        packages.insert(parent.clone());
+        disabled
+            .entry(child.package.clone())
+            .or_insert_with(|| (vec![], None));
+        let t = disabled.entry(parent).or_insert_with(|| (vec![], None));
+        t.0.push(child);
+    }
+
+    let mut packages_len = packages.len();
+    while packages_len > 0 {
+        let mut new_packages: BTreeSet<Package> = BTreeSet::new();
+        for package in packages {
+            let (_, count) = disabled.get(&package).unwrap();
+            if count.is_none() && !process(&package, &mut disabled) {
+                new_packages.insert(package.clone());
+            }
+        }
+        packages = new_packages;
+        packages_len = packages.len();
+    }
+
+    let mut v: Vec<_> = disabled
+        .into_iter()
+        .map(|(package, (_, count))| (count, package))
+        .collect();
+    v.sort();
+    for (count, package) in v {
+        let count = count.unwrap();
+        if count != 0 {
+            println!("{package} is disabled with {count} dependents");
+        }
+    }
+}
+
+fn process(package: &Package, m: &mut M) -> bool {
+    let (children, count) = m.get(package).unwrap();
+    assert!(count.is_none(), "{:?}", package);
+    let mut count = 0;
+    for child in children {
+        let (_, child_count) = m
+            .get(&child.package)
+            .unwrap_or_else(|| panic!("{}", child.package));
+        match child_count {
+            None => return false,
+            Some(i) => count += 1 + i,
+        }
+    }
+    m.entry(package.clone())
+        .and_modify(|tup| tup.1 = Some(count))
+        .or_insert_with(|| panic!("{}", package));
+    true
+}

etc/commenter/src/main.rs

@@ -19,19 +19,21 @@ enum Header {
     about = "Automates generation of bounds in  build-constraints.yaml"
 )]
 enum Opt {
-    Clear,
     Add,
-    Outdated,
+    Clear,
     DiffSnapshot { a: String, b: String },
+    Disabled,
+    Outdated,
 }
 
 fn main() {
     let opt = Opt::from_args();
     match opt {
-        Opt::Clear => commenter::clear(),
         Opt::Add => add(),
-        Opt::Outdated => commenter::outdated(),
+        Opt::Clear => commenter::clear(),
         Opt::DiffSnapshot { a, b } => commenter::diff_snapshot(a, b),
+        Opt::Disabled => commenter::disabled(),
+        Opt::Outdated => commenter::outdated(),
     }
 }