fix(git-clone): use unique temp file for post_clone_script to avoid race condition (#601)

## Summary

Fixes a race condition when multiple `git-clone` modules with
`post_clone_script` run concurrently.

## Problem

All instances of the git-clone module use the same hardcoded
`/tmp/post_clone.sh` path. When multiple modules run concurrently (or
overlap), they collide on the same temp file, causing:

```
rm: cannot remove '/tmp/post_clone.sh': No such file or directory
```

This results in a non-zero exit code, causing the workspace to appear
unhealthy.

## Solution

Use `mktemp` to generate a unique temporary filename for each module
instance:

```bash
POST_CLONE_TMP=$(mktemp /tmp/post_clone_XXXXXX.sh)
```

This ensures each concurrent execution uses its own temp file,
eliminating the race condition.

Fixes #600

---------

Co-authored-by: blink-so[bot] <211532188+blink-so[bot]@users.noreply.github.com>
Co-authored-by: Matyas Danter <mdanter@gmail.com>

registry/coder/modules/git-clone/README.md

@@ -14,7 +14,7 @@ This module allows you to automatically clone a repository by URL and skip if it
 module "git-clone" {
   count    = data.coder_workspace.me.start_count
   source   = "registry.coder.com/coder/git-clone/coder"
-  version  = "1.2.2"
+  version  = "1.2.3"
   agent_id = coder_agent.example.id
   url      = "https://github.com/coder/coder"
 }
@@ -28,7 +28,7 @@ module "git-clone" {
 module "git-clone" {
   count    = data.coder_workspace.me.start_count
   source   = "registry.coder.com/coder/git-clone/coder"
-  version  = "1.2.2"
+  version  = "1.2.3"
   agent_id = coder_agent.example.id
   url      = "https://github.com/coder/coder"
   base_dir = "~/projects/coder"
@@ -43,11 +43,12 @@ To use with [Git Authentication](https://coder.com/docs/v2/latest/admin/git-prov
 module "git-clone" {
   count    = data.coder_workspace.me.start_count
   source   = "registry.coder.com/coder/git-clone/coder"
-  version  = "1.2.2"
+  version  = "1.2.3"
   agent_id = coder_agent.example.id
   url      = "https://github.com/coder/coder"
 }
 
+
 data "coder_external_auth" "github" {
   id = "github"
 }
@@ -69,11 +70,12 @@ data "coder_parameter" "git_repo" {
 module "git_clone" {
   count    = data.coder_workspace.me.start_count
   source   = "registry.coder.com/coder/git-clone/coder"
-  version  = "1.2.2"
+  version  = "1.2.3"
   agent_id = coder_agent.example.id
   url      = data.coder_parameter.git_repo.value
 }
 
+
 # Create a code-server instance for the cloned repository
 module "code-server" {
   count    = data.coder_workspace.me.start_count
@@ -103,13 +105,14 @@ Configuring `git-clone` for a self-hosted GitHub Enterprise Server running at `g
 module "git-clone" {
   count    = data.coder_workspace.me.start_count
   source   = "registry.coder.com/coder/git-clone/coder"
-  version  = "1.2.2"
+  version  = "1.2.3"
   agent_id = coder_agent.example.id
   url      = "https://github.example.com/coder/coder/tree/feat/example"
   git_providers = {
     "https://github.example.com/" = {
       provider = "github"
     }
+
   }
 }
 ```
@@ -122,7 +125,7 @@ To GitLab clone with a specific branch like `feat/example`
 module "git-clone" {
   count    = data.coder_workspace.me.start_count
   source   = "registry.coder.com/coder/git-clone/coder"
-  version  = "1.2.2"
+  version  = "1.2.3"
   agent_id = coder_agent.example.id
   url      = "https://gitlab.com/coder/coder/-/tree/feat/example"
 }
@@ -134,13 +137,14 @@ Configuring `git-clone` for a self-hosted GitLab running at `gitlab.example.com`
 module "git-clone" {
   count    = data.coder_workspace.me.start_count
   source   = "registry.coder.com/coder/git-clone/coder"
-  version  = "1.2.2"
+  version  = "1.2.3"
   agent_id = coder_agent.example.id
   url      = "https://gitlab.example.com/coder/coder/-/tree/feat/example"
   git_providers = {
     "https://gitlab.example.com/" = {
       provider = "gitlab"
     }
+
   }
 }
 ```
@@ -155,7 +159,7 @@ For example, to clone the `feat/example` branch:
 module "git-clone" {
   count       = data.coder_workspace.me.start_count
   source      = "registry.coder.com/coder/git-clone/coder"
-  version     = "1.2.2"
+  version     = "1.2.3"
   agent_id    = coder_agent.example.id
   url         = "https://github.com/coder/coder"
   branch_name = "feat/example"
@@ -173,7 +177,7 @@ For example, this will clone into the `~/projects/coder/coder-dev` folder:
 module "git-clone" {
   count       = data.coder_workspace.me.start_count
   source      = "registry.coder.com/coder/git-clone/coder"
-  version     = "1.2.2"
+  version     = "1.2.3"
   agent_id    = coder_agent.example.id
   url         = "https://github.com/coder/coder"
   folder_name = "coder-dev"
@@ -191,8 +195,8 @@ If not defined, the default, `0`, performs a full clone.
 ```tf
 module "git-clone" {
   count    = data.coder_workspace.me.start_count
-  source   = "registry.coder.com/modules/git-clone/coder"
-  version  = "1.2.2"
+  source   = "registry.coder.com/coder/git-clone/coder"
+  version  = "1.2.3"
   agent_id = coder_agent.example.id
   url      = "https://github.com/coder/coder"
   depth    = 1
@@ -208,7 +212,7 @@ This is useful for running initialization tasks like installing dependencies or
 module "git-clone" {
   count             = data.coder_workspace.me.start_count
   source            = "registry.coder.com/coder/git-clone/coder"
-  version           = "1.2.2"
+  version           = "1.2.3"
   agent_id          = coder_agent.example.id
   url               = "https://github.com/coder/coder"
   post_clone_script = <<-EOT

registry/coder/modules/git-clone/run.sh

@@ -58,9 +58,10 @@ fi
 # Run post-clone script if provided
 if [ -n "$POST_CLONE_SCRIPT" ]; then
   echo "Running post-clone script..."
-  echo "$POST_CLONE_SCRIPT" | base64 -d > /tmp/post_clone.sh
-  chmod +x /tmp/post_clone.sh
+  POST_CLONE_TMP=$(mktemp)
+  echo "$POST_CLONE_SCRIPT" | base64 -d > "$POST_CLONE_TMP"
+  chmod +x "$POST_CLONE_TMP"
   cd "$CLONE_PATH" || exit
-  /tmp/post_clone.sh
-  rm /tmp/post_clone.sh
+  $POST_CLONE_TMP
+  rm "$POST_CLONE_TMP"
 fi