feat: Update to OPA v1.2.0 (#373)

Regorus now defaults to rego v1. `import rego.v1` is no longer needed.
Additionally, `future` keywords are automatically imported.

See
https://www.openpolicyagent.org/docs/latest/v0-upgrade/#changes-to-rego-in-opa-v10
to understand the differences between rego v1 and v0.

BREAKING CHANGE:

v0 style policies will error out by default. To enable v0 behavior, call engine.set_rego_v0(true) before
loading policies.

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

examples/regorus.rs

@@ -42,7 +42,7 @@ fn rego_eval(
     enable_tracing: bool,
     non_strict: bool,
     #[cfg(feature = "coverage")] coverage: bool,
-    v1: bool,
+    v0: bool,
 ) -> Result<()> {
     // Create engine.
     let mut engine = regorus::Engine::new();
@@ -52,7 +52,7 @@ fn rego_eval(
     #[cfg(feature = "coverage")]
     engine.set_enable_coverage(coverage);
 
-    engine.set_rego_v1(v1);
+    engine.set_rego_v0(v0);
 
     // Load files from given bundles.
     for dir in bundles.iter() {
@@ -238,9 +238,9 @@ enum RegorusCommand {
         #[arg(long, short)]
         coverage: bool,
 
-        /// Turn on rego.v1
+        /// Turn on Rego language v0.
         #[arg(long)]
-        v1: bool,
+        v0: bool,
     },
 
     /// Tokenize a Rego policy.
@@ -282,7 +282,7 @@ fn main() -> Result<()> {
             non_strict,
             #[cfg(feature = "coverage")]
             coverage,
-            v1,
+            v0,
         } => rego_eval(
             &bundles,
             &data,
@@ -292,7 +292,7 @@ fn main() -> Result<()> {
             non_strict,
             #[cfg(feature = "coverage")]
             coverage,
-            v1,
+            v0,
         ),
         RegorusCommand::Lex { file, verbose } => rego_lex(file, verbose),
         RegorusCommand::Parse { file } => rego_parse(file),

examples/server/allowed_server.rego

@@ -2,22 +2,22 @@ package example
 
 default allow := false                              # unless otherwise defined, allow is false
 
-allow := true {                                     # allow is true if...
+allow := true if {                                     # allow is true if...
     count(violation) == 0                           # there are zero violations.
 }
 
-violation[server.id] {                              # a server is in the violation set if...
+violation[server.id] if {                              # a server is in the violation set if...
     some server
     public_server[server]                           # it exists in the 'public_server' set and...
     server.protocols[_] == "http"                   # it contains the insecure "http" protocol.
 }
 
-violation[server.id] {                              # a server is in the violation set if...
+violation[server.id] if {                              # a server is in the violation set if...
     server := input.servers[_]                      # it exists in the input.servers collection and...
     server.protocols[_] == "telnet"                 # it contains the "telnet" protocol.
 }
 
-public_server[server] {                             # a server exists in the public_server set if...
+public_server[server]if  {                             # a server exists in the public_server set if...
     some i, j
     server := input.servers[_]                      # it exists in the input.servers collection and...
     server.ports[_] == input.ports[i].id            # it references a port in the input.ports collection and...