Add path filtering support to version.json

doc/pathFilters.md

@@ -0,0 +1,59 @@
+# Path filters
+
+## Problem
+
+Some repositories may contain more than project. This is sometimes referred to as a _mono repo_ (as opposed to having a repo for each project - _many repo_). Imagine a repository structured as:
+
+- /
+  - Foo/
+    - version.json => `{"version": "1.0"}`
+  - Bar/
+    - version.json => `{"version": "2.1"}`
+  - Quux/
+    - version.json => `{"version": "4.3"}`
+  - README.md
+
+With GitVersioning's default configuration, a commit to a given project's subtree will result in the version height bumping for all projects in the repository. This is typically not desirable. Intuitively, a commit to `Bar` should only cause a version bump for `Bar`, and not `Foo` or `Quux`.
+
+## Solution
+
+Path filters provide a way to filter which subtrees in the repository affect version height. Imagine the `version.json` files had a `pathFilter` property:
+
+```json
+{
+  "version": "1.0",
+  "pathFilters": ["."]
+}
+```
+
+With this single path filter of `"."`, the version height for this project would only bump when a commit was made within that subtree. Now imagine all projects in the original example have this value for `pathFilters`. Consider the following commits to the repository, and note their effect on the version height for each project:
+
+| Paths changed                            | Result                                                                     |
+| ---------------------------------------- | -------------------------------------------------------------------------- |
+| `/README.md`                             | Commit does not affect any project. No versions change.                    |
+| `/Bar/Program.cs`<br>`/Quux/Quux.csproj` | Commit affects both `Bar` and `Quux`. Their patch versions will bump by 1. |
+| `/Bar/MyClass.cs`                        | Commit affects only `Bar`. `Bar`'s patch version will bump by 1.           |
+
+When absent, the implied value for `pathFilters` is:
+
+```json
+{
+  "pathFilters": [":/"]
+}
+```
+
+This results in the entire repository tree being considered for version height calculations. This is the default behavior for GitVersioning.
+
+## Path filter format
+
+Path filters take on a variety of formats, and can specify paths relative to the `version.json` or relative to the root of the repository. See the [Path filter format](#path-filter-format) section for more information.
+
+Multiple path filters may also be specified. The order is irrelevant. After a path matches any non-exclude path filter, it will be run through all exclude path filter. If it matches, the path is ignored.
+
+| Path filter                                                                         | Description                                                                                                |
+| ----------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------- |
+| `file-here.txt`<br>`./quux.txt`<br>`./sub-dir/foo.txt`<br>`../subdir/inclusion.txt` | File will be included. Path is relative to the `version.json` file.                                        |
+| `sub-dir`<br>`../sub-dir`                                                           | Directory will be included. Path is relative to the `version.json` file.                                   |
+| `:/dir/file.txt`                                                                    | File will be included. Path is absolute (i.e., relative to the root of the repository).                    |
+| `:!bar.txt`<br>`:^../foo/baz.txt`                                                   | File will be excluded. Path is relative to the `version.json` file. `:!` and `:^` prefixes are synonymous. |
+| `:!/root-file.txt`                                                                  | File will be excluded. Path is absolute (i.e., relative to the root of the repository).                    |

doc/versionJson.md

@@ -33,6 +33,9 @@ The content of the version.json file is a JSON serialized object with these prop
   "nugetPackageVersion": {
      "semVer": 1 // optional. Set to either 1 or 2 to control how the NuGet package version string is generated. Default is 1.
   },
+  "pathFilters": [
+    // optional list of paths to consider when calculating version height.
+  ]
   "publicReleaseRefSpec": [
     "^refs/heads/master$", // we release out of master
     "^refs/tags/v\\d+\\.\\d+" // we also release tags starting with vN.N
@@ -70,3 +73,5 @@ The `publicReleaseRefSpec` field causes builds out of certain branches or tags
 to automatically drop the `-gabc123` git commit ID suffix from the version, making it
 convenient to build releases out of these refs with a friendly version number
 that assumes linear versioning.
+
+[Learn more about pathFilters](pathFilters.md).

readme.md

@@ -58,6 +58,7 @@ Also some special [cloud build considerations](doc/cloudbuild.md).
 
 This package calculates the version based on a combination of the version.json file,
 the git 'height' of the version, and the git commit ID.
+The height can optionally be incremented only for those [commits that change certain paths](doc/pathFilters.md).
 
 ### Version generation
 

src/NerdBank.GitVersioning.Tests/FilterPathTests.cs

@@ -0,0 +1,106 @@
+using System;
+using Nerdbank.GitVersioning;
+using Xunit;
+
+public class FilterPathTests
+{
+    [Theory]
+    [InlineData("./", "foo", "foo")]
+    [InlineData("../relative-dir", "foo", "relative-dir")]
+    [InlineData("../../some/dir/here", "foo/multi/wow", "foo/some/dir/here")]
+    [InlineData("relativepath.txt", "foo", "foo/relativepath.txt")]
+    [InlineData("./relativepath.txt", "foo", "foo/relativepath.txt")]
+    [InlineData("./dir\\hi/relativepath.txt", "foo", "foo/dir/hi/relativepath.txt")]
+    [InlineData(".\\relativepath.txt", "foo", "foo/relativepath.txt")]
+    [InlineData(":^relativepath.txt", "foo", "foo/relativepath.txt")]
+    [InlineData(":!relativepath.txt", "foo", "foo/relativepath.txt")]
+    [InlineData(":!/absolutepath.txt", "foo", "absolutepath.txt")]
+    [InlineData(":!\\absolutepath.txt", "foo", "absolutepath.txt")]
+    [InlineData("../bar/relativepath.txt", "foo", "bar/relativepath.txt")]
+    [InlineData("/", "foo", "")]
+    [InlineData("/absolute/file.txt", "foo", "absolute/file.txt")]
+    [InlineData(":/", "foo", "")]
+    [InlineData(":/absolutepath.txt", "foo", "absolutepath.txt")]
+    [InlineData(":/bar/absolutepath.txt", "foo", "bar/absolutepath.txt")]
+    [InlineData(":\\bar\\absolutepath.txt", "foo", "bar/absolutepath.txt")]
+    public void CanBeParsedToRepoRelativePath(string pathSpec, string relativeTo, string expected)
+    {
+        Assert.Equal(expected, new FilterPath(pathSpec, relativeTo).RepoRelativePath);
+    }
+
+    [Theory]
+    [InlineData(":!.", "foo", "foo")]
+    [InlineData(":!.", "foo", "foo/")]
+    [InlineData(":!.", "foo", "foo/relativepath.txt")]
+    [InlineData(":!relativepath.txt", "foo", "foo/relativepath.txt")]
+    [InlineData(":^relativepath.txt", "foo", "foo/relativepath.txt")]
+    [InlineData(":^./relativepath.txt", "foo", "foo/relativepath.txt")]
+    [InlineData(":^../bar", "foo", "bar")]
+    [InlineData(":^../bar", "foo", "bar/")]
+    [InlineData(":^../bar", "foo", "bar/somefile.txt")]
+    [InlineData(":^/absolute.txt", "foo", "absolute.txt")]
+    public void PathsCanBeExcluded(string pathSpec, string relativeTo, string repoRelativePath)
+    {
+        Assert.True(new FilterPath(pathSpec, relativeTo, true).Excludes(repoRelativePath));
+        Assert.True(new FilterPath(pathSpec, relativeTo, false).Excludes(repoRelativePath));
+    }
+
+    [Theory]
+    [InlineData(":!.", "foo", "foo.txt")]
+    [InlineData(":^relativepath.txt", "foo", "foo2/relativepath.txt")]
+    [InlineData(":^/absolute.txt", "foo", "absolute.txt.bak")]
+    [InlineData(":^/absolute.txt", "foo", "absolute")]
+
+    // Not exclude paths
+    [InlineData(":/absolute.txt", "foo", "absolute.txt")]
+    [InlineData("/absolute.txt", "foo", "absolute.txt")]
+    [InlineData("../root.txt", "foo", "root.txt")]
+    [InlineData("relativepath.txt", "foo", "foo/relativepath.txt")]
+    public void NonMatchingPathsAreNotExcluded(string pathSpec, string relativeTo, string repoRelativePath)
+    {
+        Assert.False(new FilterPath(pathSpec, relativeTo, true).Excludes(repoRelativePath));
+        Assert.False(new FilterPath(pathSpec, relativeTo, false).Excludes(repoRelativePath));
+    }
+
+    [Theory]
+    [InlineData(":!.", "foo", "Foo")]
+    [InlineData(":!.", "foo", "Foo/")]
+    [InlineData(":!.", "foo", "Foo/relativepath.txt")]
+    [InlineData(":!RelativePath.txt", "foo", "foo/relativepath.txt")]
+    [InlineData(":^relativepath.txt", "foo", "Foo/RelativePath.txt")]
+    [InlineData(":^./relativepath.txt", "Foo", "foo/RelativePath.txt")]
+    [InlineData(":^../bar", "foo", "Bar")]
+    [InlineData(":^../bar", "foo", "Bar/")]
+    [InlineData(":^../bar", "foo", "Bar/SomeFile.txt")]
+    [InlineData(":^/absOLUte.txt", "foo", "Absolute.TXT")]
+    public void PathsCanBeExcludedCaseInsensitive(string pathSpec, string relativeTo, string repoRelativePath)
+    {
+        Assert.True(new FilterPath(pathSpec, relativeTo, true).Excludes(repoRelativePath));
+    }
+
+    [Theory]
+    [InlineData(":!.", "foo", "Foo")]
+    [InlineData(":!.", "foo", "Foo/")]
+    [InlineData(":!.", "foo", "Foo/relativepath.txt")]
+    [InlineData(":!RelativePath.txt", "foo", "foo/relativepath.txt")]
+    [InlineData(":^relativepath.txt", "foo", "Foo/RelativePath.txt")]
+    [InlineData(":^./relativepath.txt", "Foo", "foo/RelativePath.txt")]
+    [InlineData(":^../bar", "foo", "Bar")]
+    [InlineData(":^../bar", "foo", "Bar/")]
+    [InlineData(":^../bar", "foo", "Bar/SomeFile.txt")]
+    [InlineData(":^/absOLUte.txt", "foo", "Absolute.TXT")]
+    public void NonMatchingPathsAreNotExcludedCaseSensitive(string pathSpec, string relativeTo, string repoRelativePath)
+    {
+        Assert.False(new FilterPath(pathSpec, relativeTo, false).Excludes(repoRelativePath));
+    }
+
+    [Fact]
+    public void InvalidPathspecsThrow()
+    {
+        Assert.Throws<ArgumentNullException>(() => new FilterPath(null, ""));
+        Assert.Throws<ArgumentException>(() => new FilterPath("", ""));
+        Assert.Throws<FormatException>(() => new FilterPath(":?", ""));
+        Assert.Throws<FormatException>(() => new FilterPath("../foo.txt", ""));
+        Assert.Throws<FormatException>(() => new FilterPath(".././a/../../foo.txt", "foo"));
+    }
+}