Fix the generative tests broken by PR #41 (redux) (#45)

* Use https repository for usethesource.io

This repository is necessary to get the io.usethesource.capsule  test dependency.

Since maven 3.8.1 HTTP repositories are blocked by default. See
https://maven.apache.org/docs/3.8.1/release-notes.html

* fix DiffList linear and forked methods

* Reset the slice when doing a linear set op on a DiffList.

I believe it needs to be reset because the new underlying collection is
the result of applying the old slice, so it should never be sliced
again.

This resolves the error in test-linear-list that shrinks to
[:concat [0 0]] [:diff-wrap] [:linear] [:remove-last] [:set 0 0]

* Maintain linear property in DiffList on prefix, suffix and slice while slicing.

* Clean up formatting on my change a bit

---------

Co-authored-by: Titouan Vervack <[email protected]>
Co-authored-by: Mike Barborak <[email protected]>
Co-authored-by: Zach Tellman <[email protected]>

src/io/lacuna/bifurcan/diffs/DiffList.java

@@ -60,7 +60,7 @@ public IList<V> slice(long start, long end) {
     long pSize = prefix().size();
     List<V> prefix = start < pSize
         ? this.prefix.slice(start, Math.min(pSize, end))
-        : List.EMPTY;
+        : (isLinear() ? List.EMPTY.linear() : List.EMPTY);
 
     start -= pSize;
     end -= pSize;
@@ -79,11 +79,15 @@ public IList<V> slice(long start, long end) {
 
     List<V> suffix = end > 0
         ? this.suffix.slice(max(0, start), end)
-        : List.EMPTY;
+        : (isLinear()
+              ? List.EMPTY.linear()
+              : List.EMPTY);
 
     return slicePrime.size(underlying) == 0
         ? Lists.concat(prefix, suffix)
-        : new DiffList<>(underlying, prefix, suffix, slicePrime);
+        : (isLinear()
+              ? new DiffList<>(underlying, prefix, suffix, slicePrime)
+              : new DiffList<>(underlying, prefix, suffix, slicePrime).linear());
   }
 
   @Override
@@ -170,6 +174,7 @@ public IList<V> set(long idx, V value) {
       IList<V> underlyingPrime = new ConcatList<>(slice.apply(underlying)).set(idx, value);
       if (isLinear()) {
         underlying = underlyingPrime;
+        this.slice = Slice.FULL;
         return this;
       } else {
         return new DiffList<>(underlyingPrime, prefix, suffix, Slice.FULL);
@@ -188,12 +193,12 @@ public boolean isLinear() {
 
   @Override
   public DiffList<V> forked() {
-    return isLinear() ? new DiffList<>(underlying, prefix.linear(), suffix.linear(), slice) : this;
+    return isLinear() ? new DiffList<>(underlying, prefix.forked(), suffix.forked(), slice) : this;
   }
 
   @Override
   public DiffList<V> linear() {
-    return isLinear() ? this : new DiffList<>(underlying, prefix.forked(), suffix.forked(), slice);
+    return isLinear() ? this : new DiffList<>(underlying, prefix.linear(), suffix.linear(), slice);
   }
 
   @Override

test/bifurcan/list_tests.clj

@@ -3,7 +3,7 @@
    [clojure.test :refer :all])
   (:import
    [io.lacuna.bifurcan
-    List]))
+    LinearList List]))
 
 ;; Access some private constants in the Java implementation, so some
 ;; tests can be parameterized based upon those values.
@@ -92,3 +92,13 @@
     (is (= true (same-seq l3 r3)))
     (let [l4 (.slice l3 1 10)]
       (is (= true (same-seq l4 r4))))))
+
+(deftest github-issue-40-test
+  (let [l1 (.slice (LinearList/from (range 1 3)) 0 1)
+        l2 (.linear l1)
+        l3 (.forked l2)]
+    (is (= (same-seq l2 (range 1 2)) true) "l2 has correct contents")
+    (is (= (same-seq l3 (range 1 2)) true) "l3 has correct contents")
+    (is (= (.isLinear l2) true) "l2 is linear")
+    (is (= (.isLinear l3) false) "l3 is forked")))
+