PSProxmoxVE/DECISIONS.md

Architectural Decisions

This file documents patterns that were deliberately chosen or changed, anti-patterns that were explicitly removed, and constraints that must be maintained. Read this before writing any new code.

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D001 — Task polling must use TaskService.WaitForTask

Status: Active Finding refs: F032, F033, F036, F058 Resolved in scan: 2026-03-22 (for VM/network cmdlets); container snapshot + storage cmdlets still open

Decision

All task-polling loops must use TaskService.WaitForTask(upid, session, timeout, progress). Never implement inline while(true) or do/while polling loops in cmdlet files.

Rationale

Four VM/network cmdlets (InvokePveNetworkApply, NewPveSnapshot, RestorePveSnapshot, RemovePveSnapshot) and one guest exec cmdlet had copy-pasted polling loops with no timeout, causing cmdlets to hang indefinitely if a PVE task stalled. TaskService.WaitForTask has timeout enforcement, failure detection, and WriteProgress support.

Five additional cmdlets (3 container snapshot + 2 storage) still have this anti-pattern as of scan 2026-03-22 (F058).

Anti-pattern (do not reintroduce)

// NEVER do this in a cmdlet
while (true)
{
    var status = taskService.GetTask(upid, session);
    if (status.IsFinished) break;
    Thread.Sleep(1000);
}

Correct pattern

// Always use this
TaskService.WaitForTask(upid, session, TimeoutSeconds, this);

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D002 — Password parameters must use SecureString

Status: Active Finding refs: F051 Resolved in scan: 2026-03-22

Decision

All cmdlet parameters that accept passwords must use SecureString type with Marshal.SecureStringToGlobalAllocUnicode + ZeroFreeGlobalAllocUnicode in a try/finally block for extraction.

Rationale

Set-PveVmGuestPassword originally accepted a plain string password parameter, leaving the credential in managed memory indefinitely. SecureString minimizes the window of exposure and is consistent with Connect-PveServer's PSCredential handling.

Anti-pattern (do not reintroduce)

// NEVER accept passwords as plain strings
[Parameter(Mandatory = true)]
public string Password { get; set; }

Correct pattern

[Parameter(Mandatory = true)]
public SecureString Password { get; set; }

// In ProcessRecord:
IntPtr ptr = IntPtr.Zero;
try
{
    ptr = Marshal.SecureStringToGlobalAllocUnicode(Password);
    string plainText = Marshal.PtrToStringUni(ptr);
    // Use plainText for API call
}
finally
{
    if (ptr != IntPtr.Zero)
        Marshal.ZeroFreeGlobalAllocUnicode(ptr);
}

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D003 — URL encoding required for all path parameters

Status: Active Finding refs: F050 Resolved in scan: 2026-03-22

Decision

All user-supplied or dynamic values interpolated into API URL paths must be wrapped in Uri.EscapeDataString(). This applies to all service classes.

Rationale

Snapshot names, node names, user IDs, and other identifiers could theoretically contain characters that break URL path segments. While most values come from validated sources, defense-in-depth requires consistent encoding. Applied across all 14 service classes.

Anti-pattern (do not reintroduce)

// NEVER interpolate raw strings into URL paths
var resource = $"nodes/{node}/qemu/{vmid}/snapshot/{snapshotName}";

Correct pattern

var resource = $"nodes/{Uri.EscapeDataString(node)}/qemu/{vmid}/snapshot/{Uri.EscapeDataString(snapshotName)}";

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D004 — No bare catch blocks

Status: Active Finding refs: F039 Resolved in scan: 2026-03-22

Decision

No bare catch { } or catch (Exception) { } blocks. All catch blocks must either:

1. Use a specific exception type (catch (PveApiException ex)), or
2. Use a filtered catch with when clause that excludes fatal exceptions (catch (Exception ex) when (ex is not OutOfMemoryException and not StackOverflowException))

Rationale

Bare catches in PveHttpClient, PveCmdletBase, VmService, ContainerService, and GetPveVmCmdlet silently swallowed errors, making debugging impossible. Replacing with filtered or specific catches preserves error visibility while still handling expected transient failures.

Anti-pattern (do not reintroduce)

// NEVER use bare catches
try { ... }
catch { }

// NEVER catch all exceptions unfiltered
try { ... }
catch (Exception) { /* ignore */ }

Correct pattern

// Catch specific exceptions
try { ... }
catch (PveApiException ex) { WriteWarning(ex.Message); }

// Or use filtered catch for status polling
try { ... }
catch (Exception ex) when (ex is not OutOfMemoryException and not StackOverflowException)
{
    WriteVerbose($"Status poll failed: {ex.Message}");
}

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D005 — OutputType required on all cmdlets

Status: Active Finding refs: F037 Resolved in scan: 2026-03-22

Decision

Every cmdlet must have an [OutputType(typeof(...))] attribute declaring its return type.

Rationale

~54 cmdlets were missing OutputType, degrading IntelliSense, pipeline type inference, and Get-Command -OutputType queries. All 169 cmdlets now have the attribute.

Correct pattern

[Cmdlet(VerbsCommon.Get, "PveVm")]
[OutputType(typeof(VmInfo))]
public sealed class GetPveVmCmdlet : PveCmdletBase

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D006 — ConfirmImpact.High required for destructive operations

Status: Active Finding refs: F011, F034, F042, F043, F062, F063 Resolved in scan: 2026-03-22 (for VM cmdlets); container Restart/Suspend still open

Decision

All cmdlets that perform destructive or disruptive operations must set ConfirmImpact = ConfirmImpact.High in the [Cmdlet] attribute. This includes:

• All Remove-* cmdlets
• All Stop-* cmdlets
• All Reset-* cmdlets
• All Restart-* cmdlets
• All Suspend-* cmdlets
• Restore-PveSnapshot and Restore-PveContainerSnapshot
• New-PveTemplate (irreversible conversion)

Rationale

Stop-PveVm, Reset-PveVm, Suspend-PveVm, Restart-PveVm, and Remove-PveRole were missing ConfirmImpact.High, meaning users could accidentally perform disruptive operations without being prompted. Container counterparts (Restart/Suspend) remain inconsistent as of F062/F063.

Correct pattern

[Cmdlet(VerbsLifecycle.Stop, "PveVm", SupportsShouldProcess = true,
    ConfirmImpact = ConfirmImpact.High)]

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D007 — All cmdlet classes must be sealed

Status: Active Finding refs: F041 Resolved in scan: 2026-03-22

Decision

All cmdlet classes must be declared sealed. Cmdlets are not designed for inheritance and sealing prevents unintended extension.

Rationale

~95 cmdlets were not sealed. Sealing all 169 cmdlets makes the design intent explicit and enables potential JIT optimizations.

Correct pattern

public sealed class GetPveVmCmdlet : PveCmdletBase

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D008 — JSON serialization: Newtonsoft.Json only

Status: Active Finding refs: F044 Resolved in scan: 2026-03-22

Decision

Use only Newtonsoft.Json ([JsonProperty]) for JSON serialization attributes on model classes. Do not add System.Text.Json ([JsonPropertyName]) attributes.

Rationale

The module uses Newtonsoft.Json for all API response deserialization. Having both [JsonProperty] and [JsonPropertyName] attributes was redundant and confusing — System.Text.Json is not used at runtime. All [JsonPropertyName] attributes were removed.

Anti-pattern (do not reintroduce)

// NEVER add System.Text.Json attributes alongside Newtonsoft
[JsonProperty("status")]
[JsonPropertyName("status")]  // Don't add this
public string Status { get; set; }

Correct pattern

[JsonProperty("status")]
public string Status { get; set; }

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D009 — Framework targeting: netstandard2.0 for publishable, net10.0+net48 for tests

Status: Active Finding refs: F047, F064 Status note: net9.0 → net10.0 migration still pending

Decision

• Publishable projects (PSProxmoxVE, PSProxmoxVE.Core): Target netstandard2.0 for maximum compatibility (PS 5.1 Desktop + PS 7.x Core).
• Test projects: Target net10.0 (LTS) and net48 (Windows PowerShell 5.1 validation).

Rationale

.NET 9.0 reached EOL in May 2025. The test projects should use the current LTS release (net10.0). The publishable module must remain on netstandard2.0 to support both Desktop and Core editions.

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D010 — VmId parameters: nullable int with ValidateRange

Status: Active Finding refs: F012, F038 Resolved in scan: 2026-03-21 (ValidateRange), 2026-03-22 (nullable)

Decision

VmId parameters must:

1. Use int? (nullable) when the parameter is optional (e.g., firewall cmdlets that operate at cluster, node, or VM level)
2. Include [ValidateRange(100, 999999999)] to match PVE's VMID constraints
3. Use int (non-nullable) only when VmId is mandatory

Rationale

PVE requires VMIDs in range 100-999999999. Without ValidateRange, invalid IDs reach the API and return confusing errors. Using non-nullable int with default 0 for optional VmId made it impossible to distinguish "not specified" from "VM 0" in firewall cmdlets.

Correct pattern

// Mandatory VmId
[Parameter(Mandatory = true)]
[ValidateRange(100, 999999999)]
public int VmId { get; set; }

// Optional VmId (e.g., firewall cmdlets)
[Parameter()]
[ValidateRange(100, 999999999)]
public int? VmId { get; set; }

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D011 — Verb class constants required for cmdlet attributes

Status: Active Finding refs: F009 Resolved in scan: 2026-03-21

Decision

All [Cmdlet] attributes must use verb class constants (VerbsCommon.Get, VerbsLifecycle.Start, etc.) instead of hardcoded string literals.

Rationale

Reset-PveVm used [Cmdlet("Reset", ...)] instead of VerbsCommon.Reset. While "Reset" is an approved verb, using the constant ensures compile-time verification and consistency with all other cmdlets.

Anti-pattern (do not reintroduce)

[Cmdlet("Reset", "PveVm")]  // Don't use string literals

Correct pattern

[Cmdlet(VerbsCommon.Reset, "PveVm")]

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D012 — Magic strings: extract to named constants

Status: Active Finding refs: F049 Resolved in scan: 2026-03-22

Decision

Frequently used string literals (auth header names, token prefixes, etc.) should be extracted to const string fields for maintainability.

Rationale

Auth header names (PVEAPIToken=, CSRFPreventionToken) were inline string literals used in multiple places. Extracting to const string ApiTokenPrefix and CsrfHeaderName fields improves maintainability and reduces typo risk.