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Cache typed config with git config list --type=<X> #2268

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Merged
mjcheetham merged 6 commits into from
Mar 18, 2026
Merged

Cache typed config with git config list --type=<X> #2268

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cfd3298
refactor: Add config caching to reduce git process calls
derrickstolee Feb 5, 2026
625d254
test: Add cache tests and fix precedence bug
derrickstolee Feb 5, 2026
4f37e54
feat: Cache config entries by type for typed queries
derrickstolee Mar 1, 2026
3125246
feat: Gate config cache on Git 2.54.0+ version check
derrickstolee Mar 1, 2026
efec513
config: use --show-scope instead of --show-origin in cache
derrickstolee Mar 17, 2026
2d2658e
GitConfiguration: 'worktree' and 'command' count as local
derrickstolee Mar 17, 2026
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301 changes: 300 additions & 1 deletion src/shared/Core/GitConfiguration.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -108,24 +108,291 @@ public interface IGitConfiguration
void UnsetAll(GitConfigurationLevel level, string name, string valueRegex);
}

/// <summary>
/// Represents a single configuration entry with its origin and level.
/// </summary>
internal class ConfigCacheEntry
{
public string Origin { get; set; }
public string Value { get; set; }
public GitConfigurationLevel Level { get; set; }

public ConfigCacheEntry(string origin, string value)
{
Origin = origin;
Value = value;
Level = DetermineLevel(origin);
}

private static GitConfigurationLevel DetermineLevel(string origin)
{
if (string.IsNullOrEmpty(origin))
return GitConfigurationLevel.Unknown;

// Origins look like: "file:/path/to/config", "command line:", "standard input:"
if (!origin.StartsWith("file:"))
return GitConfigurationLevel.Unknown;

string path = origin.Substring(5); // Remove "file:" prefix

// System config is typically in /etc/gitconfig or $(prefix)/etc/gitconfig
if (path.Contains("/etc/gitconfig") || path.EndsWith("/gitconfig"))
return GitConfigurationLevel.System;

// Global config is typically in ~/.gitconfig or ~/.config/git/config
if (path.Contains("/.gitconfig") || path.Contains("/.config/git/config"))
return GitConfigurationLevel.Global;

// Local config is typically in .git/config within a repository
if (path.Contains("/.git/config"))
return GitConfigurationLevel.Local;

return GitConfigurationLevel.Unknown;
}
}

/// <summary>
/// Cache for Git configuration entries loaded from 'git config list --show-origin -z'.
/// </summary>
internal class ConfigCache
{
private Dictionary<string, List<ConfigCacheEntry>> _entries;
private readonly object _lock = new object();

public bool IsLoaded => _entries != null;

public void Load(string data, ITrace trace)
{
lock (_lock)
{
var entries = new Dictionary<string, List<ConfigCacheEntry>>(GitConfigurationKeyComparer.Instance);

var origin = new StringBuilder();
var key = new StringBuilder();
var value = new StringBuilder();

int i = 0;
while (i < data.Length)
{
origin.Clear();
key.Clear();
value.Clear();

// Read origin (NUL terminated)
while (i < data.Length && data[i] != '\0')
{
origin.Append(data[i++]);
}

if (i >= data.Length)
{
trace.WriteLine("Invalid Git configuration output. Expected null terminator (\\0) after origin.");
break;
}

// Skip the NUL terminator
i++;

// Read key (newline terminated)
while (i < data.Length && data[i] != '\n')
{
key.Append(data[i++]);
}

if (i >= data.Length)
{
trace.WriteLine("Invalid Git configuration output. Expected newline terminator (\\n) after key.");
break;
}

// Skip the newline terminator
i++;

// Read value (NUL terminated)
while (i < data.Length && data[i] != '\0')
{
value.Append(data[i++]);
}

if (i >= data.Length)
{
trace.WriteLine("Invalid Git configuration output. Expected null terminator (\\0) after value.");
break;
}

// Skip the NUL terminator
i++;

string keyStr = key.ToString();
var entry = new ConfigCacheEntry(origin.ToString(), value.ToString());

if (!entries.ContainsKey(keyStr))
{
entries[keyStr] = new List<ConfigCacheEntry>();
}
entries[keyStr].Add(entry);
}

_entries = entries;
}
}

public bool TryGet(string name, GitConfigurationLevel level, out string value)
{
lock (_lock)
{
if (_entries == null)
{
value = null;
return false;
}

if (!_entries.TryGetValue(name, out var entryList))
{
value = null;
return false;
}

// Find the first entry matching the level filter
foreach (var entry in entryList)
{
if (level == GitConfigurationLevel.All || entry.Level == level)
{
value = entry.Value;
return true;
}
}

value = null;
return false;
}
}

public IEnumerable<string> GetAll(string name, GitConfigurationLevel level)
{
lock (_lock)
{
if (_entries == null || !_entries.TryGetValue(name, out var entryList))
{
return Array.Empty<string>();
}

var results = new List<string>();
foreach (var entry in entryList)
{
if (level == GitConfigurationLevel.All || entry.Level == level)
{
results.Add(entry.Value);
}
}

return results;
}
}

public void Enumerate(GitConfigurationLevel level, GitConfigurationEnumerationCallback cb)
{
lock (_lock)
{
if (_entries == null)
return;

foreach (var kvp in _entries)
{
foreach (var entry in kvp.Value)
{
if (level == GitConfigurationLevel.All || entry.Level == level)
{
var configEntry = new GitConfigurationEntry(kvp.Key, entry.Value);
if (!cb(configEntry))
{
return;
}
}
}
}
}
}

public void Clear()
{
lock (_lock)
{
_entries = null;
}
}
}

public class GitProcessConfiguration : IGitConfiguration
{
private static readonly GitVersion TypeConfigMinVersion = new GitVersion(2, 18, 0);

private readonly ITrace _trace;
private readonly GitProcess _git;
private readonly ConfigCache _cache;
private readonly bool _useCache;

internal GitProcessConfiguration(ITrace trace, GitProcess git) : this(trace, git, useCache: true)
{
}

internal GitProcessConfiguration(ITrace trace, GitProcess git)
internal GitProcessConfiguration(ITrace trace, GitProcess git, bool useCache)
{
EnsureArgument.NotNull(trace, nameof(trace));
EnsureArgument.NotNull(git, nameof(git));

_trace = trace;
_git = git;
_useCache = useCache;
_cache = useCache ? new ConfigCache() : null;
}

private void EnsureCacheLoaded()
{
if (!_useCache || _cache.IsLoaded)
return;

using (ChildProcess git = _git.CreateProcess("config list --show-origin -z"))
{
git.Start(Trace2ProcessClass.Git);
// To avoid deadlocks, always read the output stream first and then wait
string data = git.StandardOutput.ReadToEnd();
git.WaitForExit();

switch (git.ExitCode)
{
case 0: // OK
_cache.Load(data, _trace);
break;
default:
_trace.WriteLine($"Failed to load config cache (exit={git.ExitCode})");
// Don't throw - fall back to individual commands
break;
}
}
}

private void InvalidateCache()
{
if (_useCache)
{
_cache.Clear();
}
}

public void Enumerate(GitConfigurationLevel level, GitConfigurationEnumerationCallback cb)
{
if (_useCache)
{
EnsureCacheLoaded();
if (_cache.IsLoaded)
{
_cache.Enumerate(level, cb);
return;
}
}

// Fall back to original implementation
string levelArg = GetLevelFilterArg(level);
using (ChildProcess git = _git.CreateProcess($"config --null {levelArg} --list"))
{
Expand Down Expand Up @@ -194,6 +461,17 @@ public void Enumerate(GitConfigurationLevel level, GitConfigurationEnumerationCa

public bool TryGet(GitConfigurationLevel level, GitConfigurationType type, string name, out string value)
{
// Use cache for raw types only - typed queries need Git's canonicalization
if (_useCache && type == GitConfigurationType.Raw)
{
EnsureCacheLoaded();
if (_cache.IsLoaded && _cache.TryGet(name, level, out value))
{
return true;
}
}

// Fall back to individual git config command for typed queries or cache miss
string levelArg = GetLevelFilterArg(level);
string typeArg = GetCanonicalizeTypeArg(type);
using (ChildProcess git = _git.CreateProcess($"config --null {levelArg} {typeArg} {QuoteCmdArg(name)}"))
Expand Down Expand Up @@ -242,6 +520,7 @@ public void Set(GitConfigurationLevel level, string name, string value)
switch (git.ExitCode)
{
case 0: // OK
InvalidateCache();
break;
default:
_trace.WriteLine($"Failed to set config entry '{name}' to value '{value}' (exit={git.ExitCode}, level={level})");
Expand All @@ -263,6 +542,7 @@ public void Add(GitConfigurationLevel level, string name, string value)
switch (git.ExitCode)
{
case 0: // OK
InvalidateCache();
break;
default:
_trace.WriteLine($"Failed to add config entry '{name}' with value '{value}' (exit={git.ExitCode}, level={level})");
Expand All @@ -285,6 +565,7 @@ public void Unset(GitConfigurationLevel level, string name)
{
case 0: // OK
case 5: // Trying to unset a value that does not exist
InvalidateCache();
break;
default:
_trace.WriteLine($"Failed to unset config entry '{name}' (exit={git.ExitCode}, level={level})");
Expand All @@ -295,6 +576,22 @@ public void Unset(GitConfigurationLevel level, string name)

public IEnumerable<string> GetAll(GitConfigurationLevel level, GitConfigurationType type, string name)
{
// Use cache for raw types only - typed queries need Git's canonicalization
if (_useCache && type == GitConfigurationType.Raw)
{
EnsureCacheLoaded();
if (_cache.IsLoaded)
{
var cachedValues = _cache.GetAll(name, level);
foreach (var val in cachedValues)
{
yield return val;
}
yield break;
}
}

// Fall back to individual git config command
string levelArg = GetLevelFilterArg(level);
string typeArg = GetCanonicalizeTypeArg(type);

Expand Down Expand Up @@ -392,6 +689,7 @@ public void ReplaceAll(GitConfigurationLevel level, string name, string valueReg
switch (git.ExitCode)
{
case 0: // OK
InvalidateCache();
break;
default:
_trace.WriteLine($"Failed to replace all multivar '{name}' and value regex '{valueRegex}' with new value '{value}' (exit={git.ExitCode}, level={level})");
Expand Down Expand Up @@ -420,6 +718,7 @@ public void UnsetAll(GitConfigurationLevel level, string name, string valueRegex
{
case 0: // OK
case 5: // Trying to unset a value that does not exist
InvalidateCache();
break;
default:
_trace.WriteLine($"Failed to unset all multivar '{name}' with value regex '{valueRegex}' (exit={git.ExitCode}, level={level})");
Expand Down