Fix prefix/subdir optimisation bug

The optimiser rule was wrong in case the subdir filter path was a
prefix of the prefix filter. It resulted in :empty in this case,
which is wrong.

Change: fix-prefix-subdir

Author: christian-schilling

src/cache.rs

@@ -1,7 +1,7 @@
 use super::*;
 use std::collections::HashMap;
 
-const CACHE_VERSION: u64 = 13;
+const CACHE_VERSION: u64 = 14;
 
 lazy_static! {
     static ref DB: std::sync::Mutex<Option<sled::Db>> = std::sync::Mutex::new(None);

src/filter/opt.rs

@@ -353,7 +353,14 @@ fn step(filter: Filter) -> Filter {
         Op::Chain(a, b) => match (to_op(a), to_op(b)) {
             (Op::Chain(x, y), b) => Op::Chain(x, to_filter(Op::Chain(y, to_filter(b)))),
             (Op::Prefix(a), Op::Subdir(b)) if a == b => Op::Nop,
-            (Op::Prefix(a), Op::Subdir(b)) if a != b => Op::Empty,
+            (Op::Prefix(a), Op::Subdir(b))
+                if a != b && a.components().count() == b.components().count() =>
+            {
+                Op::Empty
+            }
+            (Op::Prefix(a), Op::Subdir(b)) if a != b => {
+                Op::Prefix(a.strip_prefix(&b).unwrap_or(&a).to_owned())
+            }
             (Op::Nop, b) => b,
             (a, Op::Nop) => a,
             (Op::Empty, _) => Op::Empty,

tests/filter/pretty_print.t

@@ -12,6 +12,8 @@
   :/"a%\"$"
   $ josh-filter -p :/a:/b
   :/a/b
+  $ josh-filter -p :prefix=x/y:/x
+  :prefix=y
   $ josh-filter -p :[:/a:/b,:/a/b]
   :/a/b
   $ josh-filter -p :[:empty,:/a]

tests/proxy/amend_patchset.t

@@ -121,7 +121,7 @@
   "real_repo.git" = [':/sub3']
   .
   |-- josh
-  |   `-- 13
+  |   `-- 14
   |       `-- sled
   |           |-- blobs
   |           |-- conf

tests/proxy/authentication.t

@@ -124,7 +124,7 @@
   "real_repo.git" = [':/sub1']
   .
   |-- josh
-  |   `-- 13
+  |   `-- 14
   |       `-- sled
   |           |-- blobs
   |           |-- conf

tests/proxy/caching.t

@@ -48,7 +48,7 @@
   "real_repo.git" = [':/sub1']
   .
   |-- josh
-  |   `-- 13
+  |   `-- 14
   |       `-- sled
   |           |-- blobs
   |           |-- conf
@@ -156,7 +156,7 @@
   "real_repo.git" = [':/sub1']
   .
   |-- josh
-  |   `-- 13
+  |   `-- 14
   |       `-- sled
   |           |-- blobs
   |           |-- conf

tests/proxy/clone_absent_head.t

@@ -87,7 +87,7 @@
   $ bash ${TESTDIR}/destroy_test_env.sh
   .
   |-- josh
-  |   `-- 13
+  |   `-- 14
   |       `-- sled
   |           |-- blobs
   |           |-- conf

tests/proxy/clone_all.t

@@ -53,7 +53,7 @@
   "real_repo.git" = [':/sub1']
   .
   |-- josh
-  |   `-- 13
+  |   `-- 14
   |       `-- sled
   |           |-- blobs
   |           |-- conf

tests/proxy/clone_blocked.t

@@ -9,7 +9,7 @@
   $ bash ${TESTDIR}/destroy_test_env.sh
   .
   |-- josh
-  |   `-- 13
+  |   `-- 14
   |       `-- sled
   |           |-- blobs
   |           |-- conf

tests/proxy/clone_invalid_url.t

@@ -32,7 +32,7 @@
   $ bash ${TESTDIR}/destroy_test_env.sh
   .
   |-- josh
-  |   `-- 13
+  |   `-- 14
   |       `-- sled
   |           |-- blobs
   |           |-- conf