How to require commit messages in VisualSVN server

Question

We've got VisualSVN Server set up as our Subversion server on Windows, and we use Ankhsvn + TortoiseSVN as clients on our workstations.

How can you configure the server to require commit messages to be non-empty?

Answer 1

Here's a Windows Shell JScript that you can use by specifying the hook as:

%SystemRoot%\System32\CScript.exe //nologo <..path..to..script> %1 %2

It's pretty easy-to-read, so go ahead an experiment.

BTW, the reason to do this in JScript is that it does not rely on any other tools (Perl, CygWin, etc.) to be installed.

if (WScript.Arguments.Length < 2)
{
    WScript.StdErr.WriteLine("Repository Hook Error: Missing parameters. Should be REPOS_PATH then TXN_NAME, e.g. %1 %2 in pre-commit hook");
    WScript.Quit(-1);
}

var oShell = new ActiveXObject("WScript.Shell");
var oFSO = new ActiveXObject("Scripting.FileSystemObject");

var preCommitStdOut = oShell.ExpandEnvironmentStrings("%TEMP%\\PRE-COMMIT." + WScript.Arguments(1) + ".stdout");
var preCommitStdErr = oShell.ExpandEnvironmentStrings("%TEMP%\\PRE-COMMIT." + WScript.Arguments(1) + ".stderr");

var commandLine = "%COMSPEC% /C \"C:\\Program Files\\VisualSVN Server\\bin\\SVNLook.exe\" log -t ";

commandLine += WScript.Arguments(1);
commandLine += " ";
commandLine += WScript.Arguments(0);
commandLine += "> " + preCommitStdOut + " 2> " + preCommitStdErr;


// Run Synchronously, don't show a window
// WScript.Echo("About to run: " + commandLine);
var exitCode = oShell.Run(commandLine, 0, true);

var fsOUT = oFSO.GetFile(preCommitStdOut).OpenAsTextStream(1);
var fsERR = oFSO.GetFile(preCommitStdErr).OpenAsTextStream(1);

var stdout = fsOUT && !fsOUT.AtEndOfStream ? fsOUT.ReadAll() : "";
var stderr = fsERR && !fsERR.AtEndOfStream ? fsERR.ReadAll() : "";

if (stderr.length > 0)
{
    WScript.StdErr.WriteLine("Error with SVNLook: " + stderr);
    WScript.Quit(-2);
}

// To catch naught commiters who write 'blah' as their commit message

if (stdout.length < 5)
{
    WScript.StdErr.WriteLine("Please provide a commit message that describes why you've made these changes.");
    WScript.Quit(-3);
}

WScript.Quit(0);

Answer 2

VisualSVN Server 3.9 provides the VisualSVNServerHooks.exe check-logmessage pre-commit hook that helps you reject commits with empty or short log messages. See the article KB140: Validating commit log messages in VisualSVN Server for instructions.

Besides the built-in VisualSVNServerHooks.exe, VisualSVN Server and SVN in general uses a number of hooks to accomplish tasks like this.

• start-commit — run before commit transaction begins, can be used to do special permission checking
• pre-commit — run at the end of the transaction, but before commit. Often used to validate things such as a non zero length log message.
• post-commit — runs after the transaction has been committed. Can be used for sending emails, or backing up repository.
• pre-revprop-change — runs before a revision property change. Can be used to check permissions.
• post-revprop-change — runs after a revision property change. Can be used to email or backup these changes.

You need to use the pre-commit hook. You can write it yourself in just about any language your platform supports, but there are a number of scripts on the web. Googling "svn precommit hook to require comment" I found a couple that looked like they would fit the bill:

• Perl Script
• Python Script

Answer 3

We use the excellent CS-Script tool for our pre-commit hooks so that we can write scripts in the language we're doing development in. Here's an example that ensures there's a commit message longer than 10 characters, and ensures that .suo and .user files aren't checked in. You can also test for tab/space indents, or do small code standards enforcement at check-in, but be careful making your script do too much as you don't want to slow down a commit.

// run from pre-commit.cmd like so:
// css.exe /nl /c C:\SVN\Scripts\PreCommit.cs %1 %2
using System;
using System.Diagnostics;
using System.Text;
using System.Text.RegularExpressions;
using System.Linq;

class PreCommitCS {

  /// <summary>Controls the procedure flow of this script</summary>
  public static int Main(string[] args) {
    if (args.Length < 2) {
      Console.WriteLine("usage: PreCommit.cs repository-path svn-transaction");
      Environment.Exit(2);
    }

    try {
      var proc = new PreCommitCS(args[0], args[1]);
      proc.RunChecks();
      if (proc.MessageBuffer.ToString().Length > 0) {
        throw new CommitException(String.Format("Pre-commit hook violation\r\n{0}", proc.MessageBuffer.ToString()));
      }
    }
    catch (CommitException ex) {
      Console.WriteLine(ex.Message);
      Console.Error.WriteLine(ex.Message);
      throw ex;
    }
    catch (Exception ex) {
      var message = String.Format("SCRIPT ERROR! : {1}{0}{2}", "\r\n", ex.Message, ex.StackTrace.ToString());
      Console.WriteLine(message);
      Console.Error.WriteLine(message);
      throw ex;
    }

    // return success if we didn't throw
    return 0;
  }

  public string RepoPath { get; set; }
  public string SvnTx { get; set; }
  public StringBuilder MessageBuffer { get; set; }

  /// <summary>Constructor</summary>
  public PreCommitCS(string repoPath, string svnTx) {
    this.RepoPath = repoPath;
    this.SvnTx = svnTx;
    this.MessageBuffer = new StringBuilder();
  }

  /// <summary>Main logic controller</summary>
  public void RunChecks() {
    CheckCommitMessageLength(10);

    // Uncomment for indent checks
    /*
    string[] changedFiles = GetCommitFiles(
      new string[] { "A", "U" },
      new string[] { "*.cs", "*.vb", "*.xml", "*.config", "*.vbhtml", "*.cshtml", "*.as?x" },
      new string[] { "*.designer.*", "*.generated.*" }
    );
    EnsureTabIndents(changedFiles);
    */

    CheckForIllegalFileCommits(new string[] {"*.suo", "*.user"});
  }

  private void CheckForIllegalFileCommits(string[] filesToExclude) {
    string[] illegalFiles = GetCommitFiles(
      new string[] { "A", "U" },
      filesToExclude,
      new string[] {}
    );
    if (illegalFiles.Length > 0) {
      Echo(String.Format("You cannot commit the following files: {0}", String.Join(",", illegalFiles)));
    }
  }

  private void EnsureTabIndents(string[] filesToCheck) {
    foreach (string fileName in filesToCheck) {
      string contents = GetFileContents(fileName);
      string[] lines = contents.Replace("\r\n", "\n").Replace("\r", "\n").Split(new string[] { "\n" }, StringSplitOptions.None);
      var linesWithSpaceIndents =
        Enumerable.Range(0, lines.Length)
             .Where(i => lines[i].StartsWith(" "))
             .Select(i => i + 1)
             .Take(11)
             .ToList();
      if (linesWithSpaceIndents.Count > 0) {
        var message = String.Format("{0} has spaces for indents on line(s): {1}", fileName, String.Join(",", linesWithSpaceIndents));
        if (linesWithSpaceIndents.Count > 10) message += "...";
        Echo(message);
      }
    }
  }

  private string GetFileContents(string fileName) {
    string args = GetSvnLookCommandArgs("cat") + " \"" + fileName + "\"";
    string svnlookResults = ExecCmd("svnlook", args);
    return svnlookResults;
  }

  private void CheckCommitMessageLength(int minLength) {
    string args = GetSvnLookCommandArgs("log");
    string svnlookResults = ExecCmd("svnlook", args);
    svnlookResults = (svnlookResults ?? "").Trim();
    if (svnlookResults.Length < minLength) {
      if (svnlookResults.Length > 0) {
        Echo("Your commit message was too short.");
      }
      Echo("Please describe the changes you've made in a commit message in order to successfully commit. Include support ticket number if relevant.");
    }
  }

  private string[] GetCommitFiles(string[] changedIds, string[] includedFiles, string[] exclusions) {
    string args = GetSvnLookCommandArgs("changed");
    string svnlookResults = ExecCmd("svnlook", args);
    string[] lines = svnlookResults.Split(new string[] { "\r", "\n" }, StringSplitOptions.RemoveEmptyEntries);
    var includedPatterns = (from a in includedFiles select ConvertWildcardPatternToRegex(a)).ToArray();
    var excludedPatterns = (from a in exclusions select ConvertWildcardPatternToRegex(a)).ToArray();
    var opts = RegexOptions.IgnoreCase;
    var results =
      from line in lines
      let fileName = line.Substring(1).Trim()
      let changeId = line.Substring(0, 1).ToUpper()
      where changedIds.Any(x => x.ToUpper() == changeId)
      && includedPatterns.Any(x => Regex.IsMatch(fileName, x, opts))
      && !excludedPatterns.Any(x => Regex.IsMatch(fileName, x, opts))
      select fileName;
    return results.ToArray();
  }

  private string GetSvnLookCommandArgs(string cmdType) {
    string args = String.Format("{0} -t {1} \"{2}\"", cmdType, this.SvnTx, this.RepoPath);
    return args;
  }

  /// <summary>
  /// Executes a command line call and returns the output from stdout.
  /// Raises an error is stderr has any output.
  /// </summary>
  private string ExecCmd(string command, string args) {
    Process proc = new Process();
    proc.StartInfo.FileName = command;
    proc.StartInfo.Arguments = args;
    proc.StartInfo.UseShellExecute = false;
    proc.StartInfo.CreateNoWindow = true;
    proc.StartInfo.RedirectStandardOutput = true;
    proc.StartInfo.RedirectStandardError = true;
    proc.Start();

    var stdOut = proc.StandardOutput.ReadToEnd();
    var stdErr = proc.StandardError.ReadToEnd();

    proc.WaitForExit(); // Do after ReadToEnd() call per: http://chrfalch.blogspot.com/2008/08/processwaitforexit-never-completes.html

    if (!string.IsNullOrWhiteSpace(stdErr)) {
      throw new Exception(string.Format("Error: {0}", stdErr));
    }

    return stdOut;
  }

  /// <summary>
  /// Writes the string provided to the Message Buffer - this fails
  /// the commit and this message is presented to the comitter.
  /// </summary>
  private void Echo(object s) {
    this.MessageBuffer.AppendLine((s == null ? "" : s.ToString()));
  }

  /// <summary>
  /// Takes a wildcard pattern (like *.bat) and converts it to the equivalent RegEx pattern
  /// </summary>
  /// <param name="wildcardPattern">The wildcard pattern to convert.  Syntax similar to VB's Like operator with the addition of pipe ("|") delimited patterns.</param>
  /// <returns>A regex pattern that is equivalent to the wildcard pattern supplied</returns>
  private string ConvertWildcardPatternToRegex(string wildcardPattern) {
    if (string.IsNullOrEmpty(wildcardPattern)) return "";

    // Split on pipe
    string[] patternParts = wildcardPattern.Split('|');

    // Turn into regex pattern that will match the whole string with ^$
    StringBuilder patternBuilder = new StringBuilder();
    bool firstPass = true;
    patternBuilder.Append("^");
    foreach (string part in patternParts) {
      string rePattern = Regex.Escape(part);

      // add support for ?, #, *, [...], and [!...]
      rePattern = rePattern.Replace("\\[!", "[^");
      rePattern = rePattern.Replace("\\[", "[");
      rePattern = rePattern.Replace("\\]", "]");
      rePattern = rePattern.Replace("\\?", ".");
      rePattern = rePattern.Replace("\\*", ".*");
      rePattern = rePattern.Replace("\\#", "\\d");

      if (firstPass) {
        firstPass = false;
      }
      else {
        patternBuilder.Append("|");
      }
      patternBuilder.Append("(");
      patternBuilder.Append(rePattern);
      patternBuilder.Append(")");
    }
    patternBuilder.Append("$");

    string result = patternBuilder.ToString();
    if (!IsValidRegexPattern(result)) {
      throw new ArgumentException(string.Format("Invalid pattern: {0}", wildcardPattern));
    }
    return result;
  }

  private bool IsValidRegexPattern(string pattern) {
    bool result = true;
    try {
      new Regex(pattern);
    }
    catch {
      result = false;
    }
    return result;
  }
}

public class CommitException : Exception {
  public CommitException(string message) : base(message) {
  }
}

Answer 4

Prior to adding commit hooks to my server, I just distributed svnprops to the TortoiseSVN clients.

So, as an alternative:

In TortoiseSVN -> Properties property name - add/set tsvn:logminsize appropriately.

This of course is no guarantee on the server as clients/users can opt not to do it, but you can distribute svnprops files if you like. This way, users don't have to set their own values - you can provide them to all users.

This also works for things like bugtraq: settings to link issue tracking stuff in the logs.

Answer 5

What VisualSVN offers you to enter as hooks are "Windows NT command scripts", which are basically batch files.

Writing if-then-else in batch files is very ugly and probably very hard to debug.

It will look something like the following (search for pre-commit.bat) (not tested):

SVNLOOK.exe log -t "%2" "%1" | grep.exe "[a-zA-Z0-9]" > nul || GOTO ERROR
GOTO OK
:ERROR
ECHO "Please enter comment and then retry commit!"
exit 1
:OK
exit 0 

You need a grep.exe on the path, %1 is the the path to this repository, %2 the name of the txn about to be committed. Also have a look at the pre-commit.tmpl in the hooks directory of your repository.