From ee8bc39e3fe751b62ed879b45dc249e4e1ecf3b5 Mon Sep 17 00:00:00 2001
From: Rick Elrod <rick.elrod@checkmk.com>
Date: Mon, 24 Nov 2025 16:34:49 +0100
Subject: [PATCH 1/2] Windows: Try to give a nicer error if missing VC++

Without the redistributable libs, micromamba can't run. Tell the user
where to get it.
---
 src/micromamba/mod.rs    | 17 ++++++++++++++++-
 src/micromamba/result.rs |  8 ++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/micromamba/mod.rs b/src/micromamba/mod.rs
index 91ae5c3..e141510 100644
--- a/src/micromamba/mod.rs
+++ b/src/micromamba/mod.rs
@@ -39,7 +39,7 @@ fn block_on_child_exit(child: &mut std::process::Child) -> MicromambaResult {
 }
 
 fn exec_micromamba(cmd: &mut Command, stream_output: bool) -> MicromambaResult {
-    if stream_output {
+    let result = if stream_output {
         match cmd.spawn() {
             Ok(mut child) => block_on_child_exit(&mut child),
             Err(e) if e.kind() == io::ErrorKind::NotFound => {
@@ -65,7 +65,22 @@ fn exec_micromamba(cmd: &mut Command, stream_output: bool) -> MicromambaResult {
                 MicromambaResult::CouldNotRun
             }
         }
+    };
+
+    if cfg!(windows)
+        && result
+            .exit_status()
+            .and_then(|s| s.code())
+            .is_some_and(|s| s == 0xc0000135u32 as i32)
+    {
+        error!("Windows reported a missing DLL required to run micromamba");
+        error!("This error can very likely be solved by installing the VC++ runtime libraries");
+        error!(
+            "See https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170#latest-supported-redistributable-version for more information"
+        );
     }
+
+    result
 }
 
 impl<'a> Micromamba<'a> {
diff --git a/src/micromamba/result.rs b/src/micromamba/result.rs
index 91048d7..f692def 100644
--- a/src/micromamba/result.rs
+++ b/src/micromamba/result.rs
@@ -39,6 +39,14 @@ impl MicromambaResult {
             _ => ExitCode::FAILURE,
         }
     }
+
+    pub fn exit_status(&self) -> Option<ExitStatus> {
+        match self {
+            Self::StreamedOutput(exit_status) => Some(*exit_status),
+            Self::CapturedOutput(output) => Some(output.status),
+            _ => None,
+        }
+    }
 }
 
 impl From<MicromambaResult> for Result<(), ExitCode> {

From 898a7cd8beeb4e9d8a6aada711c5e0a763783847 Mon Sep 17 00:00:00 2001
From: Rick Elrod <rick.elrod@checkmk.com>
Date: Mon, 24 Nov 2025 16:36:17 +0100
Subject: [PATCH 2/2] Bump to alpha4

Signed-off-by: Rick Elrod <rick.elrod@checkmk.com>
---
 Cargo.lock | 2 +-
 Cargo.toml | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index c322c4e..4820dab 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -269,7 +269,7 @@ dependencies = [
 
 [[package]]
 name = "csm"
-version = "0.1.0-alpha3"
+version = "0.1.0-alpha4"
 dependencies = [
  "assert_cmd",
  "bzip2",
diff --git a/Cargo.toml b/Cargo.toml
index 0fe19fc..f566e89 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "csm"
-version = "0.1.0-alpha3"
+version = "0.1.0-alpha4"
 edition = "2024"
 
 [lints.clippy]