fix(pm): warn on unsupported dedupe check options

crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/pm_dedupe/snapshots.toml

@@ -22,6 +22,7 @@ vp = "global"
 cwd = "yarn"
 steps = [
   { argv = ["vp", "dedupe", "--", "--silent"], comment = "Yarn Classic falls back to install because install already deduplicates dependencies" },
+  { argv = ["vp", "dedupe", "--check", "--", "--silent"], comment = "warns about unsupported --check and still falls back to install" },
   { argv = ["vpt", "print-file", "package.json"], comment = "verify Yarn Classic completed" },
 ]
 
@@ -41,6 +42,7 @@ vp = "global"
 cwd = "bun"
 steps = [
   { argv = ["vp", "dedupe", "--", "--silent"], comment = "Bun falls back to install because it does not support dedupe" },
+  { argv = ["vp", "dedupe", "--check", "--", "--silent"], comment = "warns about unsupported --check and still falls back to install" },
   { argv = ["vpt", "print-file", "package.json"], comment = "verify Bun completed" },
 ]
 

crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/pm_dedupe/snapshots/pm_dedupe_bun.md

@@ -8,6 +8,15 @@ Bun falls back to install because it does not support dedupe
 warn: bun dedupe requires bun >= 1.4, falling back to bun install
 ```
 
+## `vp dedupe --check -- --silent`
+
+warns about unsupported --check and still falls back to install
+
+```
+warn: bun <1.4 does not support --check.
+warn: bun dedupe requires bun >= 1.4, falling back to bun install
+```
+
 ## `vpt print-file package.json`
 
 verify Bun completed

crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/pm_dedupe/snapshots/pm_dedupe_yarn.md

@@ -8,6 +8,15 @@ Yarn Classic falls back to install because install already deduplicates dependen
 warn: Yarn Classic dedupes during install, falling back to yarn install
 ```
 
+## `vp dedupe --check -- --silent`
+
+warns about unsupported --check and still falls back to install
+
+```
+warn: yarn <2 does not support --check.
+warn: Yarn Classic dedupes during install, falling back to yarn install
+```
+
 ## `vpt print-file package.json`
 
 verify Yarn Classic completed

crates/vp_pm_cli/src/resolution/commands/dedupe.rs

@@ -8,7 +8,7 @@ use crate::resolution::{
 #[derive(clap::Args, Clone, Debug, Default, PartialEq, Eq)]
 pub struct DedupeArgs {
     /// Check if deduplication would make changes
-    #[arg(long)]
+    #[arg(long, not_supported(yarn < "2", bun < "1.4"))]
     pub(crate) check: bool,
 
     /// Additional arguments to pass through to the package manager
@@ -126,6 +126,7 @@ mod tests {
 
         assert_eq!(command.program, "yarn");
         assert_eq!(command.args, vec!["dedupe", "--check"]);
+        assert!(resolution.diagnostics.is_empty());
     }
 
     #[test]
@@ -135,12 +136,14 @@ mod tests {
 
         assert_eq!(command.program, "yarn");
         assert_eq!(command.args, vec!["install"]);
-        assert_eq!(resolution.diagnostics.len(), 1);
+        assert_eq!(resolution.diagnostics.len(), 2);
+        assert_eq!(resolution.diagnostics[0].message, "yarn <2 does not support --check.");
+        assert_eq!(resolution.diagnostics[0].kind, DiagnosticKind::UnsupportedOptionDropped);
         assert_eq!(
-            resolution.diagnostics[0].message,
+            resolution.diagnostics[1].message,
             "Yarn Classic dedupes during install, falling back to yarn install"
         );
-        assert_eq!(resolution.diagnostics[0].kind, DiagnosticKind::FallbackCommand);
+        assert_eq!(resolution.diagnostics[1].kind, DiagnosticKind::FallbackCommand);
     }
 
     #[test]
@@ -158,6 +161,24 @@ mod tests {
         assert_eq!(resolution.diagnostics[0].kind, DiagnosticKind::FallbackCommand);
     }
 
+    #[test]
+    fn test_bun_dedupe_check_warns_and_falls_back_to_install() {
+        let resolution = resolve(&bun("1.3.11"), DedupeArgs { check: true, ..Default::default() });
+        let command = expect_run(resolution.outcome);
+
+        assert_eq!(command.program, "bun");
+        assert_eq!(command.args, vec!["install"]);
+        let messages =
+            resolution.diagnostics.iter().map(|entry| entry.message.as_str()).collect::<Vec<_>>();
+        assert_eq!(
+            messages,
+            vec![
+                "bun <1.4 does not support --check.",
+                "bun dedupe requires bun >= 1.4, falling back to bun install"
+            ]
+        );
+    }
+
     #[test]
     fn test_bun_dedupe_basic() {
         let resolution = resolve(&bun("1.4.0"), DedupeArgs::default());
@@ -175,6 +196,7 @@ mod tests {
 
         assert_eq!(command.program, "bun");
         assert_eq!(command.args, vec!["dedupe", "--check"]);
+        assert!(resolution.diagnostics.is_empty());
     }
 
     #[test]