From 3cbd5006c4a22709ef8a0a8e3c4d88f66aaf14ef Mon Sep 17 00:00:00 2001
From: vchirikov <vchirikov@servicetitan.com>
Date: Mon, 9 Mar 2020 02:10:58 +0300
Subject: [PATCH] Review fixes

---
 .../VersionOracleTests.cs                     |  3 +--
 src/NerdBank.GitVersioning/VersionOptions.cs  | 23 ++++++++++++++++++-
 src/NerdBank.GitVersioning/VersionOracle.cs   |  5 ++--
 .../version.schema.json                       |  2 +-
 4 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/NerdBank.GitVersioning.Tests/VersionOracleTests.cs b/src/NerdBank.GitVersioning.Tests/VersionOracleTests.cs
index e9238157..b64af102 100644
--- a/src/NerdBank.GitVersioning.Tests/VersionOracleTests.cs
+++ b/src/NerdBank.GitVersioning.Tests/VersionOracleTests.cs
@@ -323,8 +323,7 @@ public void CanSetGitCommitIdPrefixNonPublicRelease()
             {
                 SemVer = 2,
             },
-            GitCommitIdPrefix = "git"
-
+            GitCommitIdPrefix = "git",
         };
         this.WriteVersionFile(workingCopyVersion);
         this.InitializeSourceControl();
diff --git a/src/NerdBank.GitVersioning/VersionOptions.cs b/src/NerdBank.GitVersioning/VersionOptions.cs
index ca5ae85e..64c7e8e6 100644
--- a/src/NerdBank.GitVersioning/VersionOptions.cs
+++ b/src/NerdBank.GitVersioning/VersionOptions.cs
@@ -15,6 +15,9 @@
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
     public class VersionOptions : IEquatable<VersionOptions>
     {
+        [DebuggerBrowsable(DebuggerBrowsableState.Never)]
+        private string gitCommitIdPrefix;
+
         /// <summary>
         /// Default value for <see cref="VersionPrecision"/>.
         /// </summary>
@@ -60,13 +63,31 @@ public class VersionOptions : IEquatable<VersionOptions>
         [JsonProperty(DefaultValueHandling = DefaultValueHandling.Ignore)]
         public AssemblyVersionOptions AssemblyVersion { get; set; }
 
+
         /// <summary>
         /// Gets or sets the prefix for git commit id in version.
+        /// Because of semver rules the prefix must lead with a [A-z_] character (not a number) and it cannot be the empty string.
         /// If <c>null</c> 'g' will be used.
         /// </summary>
         /// <value>A prefix for git commit id.</value>
         [JsonProperty(DefaultValueHandling = DefaultValueHandling.Ignore)]
-        public string GitCommitIdPrefix { get; set; }
+        public string GitCommitIdPrefix
+        {
+            get => gitCommitIdPrefix;
+            set
+            {
+                if (string.IsNullOrWhiteSpace(value))
+                {
+                    throw new ArgumentNullException(nameof(value), $"{nameof(this.GitCommitIdPrefix)} can't be empty");
+                }
+                char first = value[0];
+                if (first < 'A' || (first > 'Z' && first < 'a' && first != '_') || first > 'z')
+                {
+                    throw new ArgumentException(nameof(value), $"{nameof(this.GitCommitIdPrefix)} must lead with a [A-z_] character (not a number)");
+                }
+                this.gitCommitIdPrefix = value;
+            }
+        }
 
         /// <summary>
         /// Gets the version to use particularly for the <see cref="AssemblyVersionAttribute"/>
diff --git a/src/NerdBank.GitVersioning/VersionOracle.cs b/src/NerdBank.GitVersioning/VersionOracle.cs
index a52dd14f..66ddc562 100644
--- a/src/NerdBank.GitVersioning/VersionOracle.cs
+++ b/src/NerdBank.GitVersioning/VersionOracle.cs
@@ -418,7 +418,7 @@ public IEnumerable<string> BuildMetadataWithCommitId
             this.PublicRelease ? string.Empty : $"-{this.GitCommitIdShort}";
 
         /// <summary>
-        /// Gets a SemVer 1.0 compliant string that represents this version, including the -{GitCommitIdPrefix}COMMITID suffix
+        /// Gets a SemVer 1.0 compliant string that represents this version, including the -gCOMMITID suffix
         /// when <see cref="PublicRelease"/> is <c>false</c>.
         /// </summary>
         private string NuGetSemVer1 =>
@@ -438,7 +438,8 @@ public IEnumerable<string> BuildMetadataWithCommitId
         private string PrereleaseVersionSemVer1 => SemanticVersionExtensions.MakePrereleaseSemVer1Compliant(this.PrereleaseVersion, this.SemVer1NumericIdentifierPadding);
 
         /// <summary>
-        /// Gets the -{<seealso cref="VersionOptions.GitCommitIdPrefix"/>}c0ffee or .<seealso cref="VersionOptions.GitCommitIdPrefix"/>c0ffee suffix for the version.
+        /// Gets the -gc0ffee or .gc0ffee suffix for the version.
+        /// The g in the prefix might be changed if <see cref="VersionOptions.GitCommitIdPrefix"/> is set.
         /// </summary>
         /// <remarks>
         /// The prefix to the commit ID is to remain SemVer2 compliant particularly when the partial commit ID we use is made up entirely of numerals.
diff --git a/src/NerdBank.GitVersioning/version.schema.json b/src/NerdBank.GitVersioning/version.schema.json
index 46ad2244..1e402b08 100644
--- a/src/NerdBank.GitVersioning/version.schema.json
+++ b/src/NerdBank.GitVersioning/version.schema.json
@@ -81,7 +81,7 @@
         },
         "gitCommitIdPrefix": {
           "type": "string",
-          "description": "The git commit prefix (e.g. 'g') in prerelease versions",
+          "description": "The git commit prefix (e.g. 'g') in non-public release versions.",
           "pattern": "^[^0-9][\\da-z\\-_\\.]*$",
           "default": "g"
         },