add classpath_dirs to clojure_repl

README.md

@@ -35,7 +35,7 @@ rules_clojure_setup()
 
 Differs from [simuons/rules_clojure](https://github.com/simuons/rules_clojure) that it uses `java_library` and `java_binary` as much as possible.
 
-`clojure_binary`, `clojure_repl` and `clojure_test` are all macros that delegate to `java_binary`. `clojure_library` is new code.
+`clojure_binary`, and `clojure_test` are macros that delegate to `java_binary`. `clojure_library` is new code.
 
 For fast compilation, `clojure_library` is a Bazel persistent worker.
 
@@ -70,10 +70,14 @@ Note that AOT will determine whether a library should appear in `deps` or `runti
 ```
 clojure_repl(
   name = "foo_repl",
-  deps = [":foo"])
+  main_class = "clojure.main",
+  main_args = ["-e", "foo.main"],
+  runtime_deps = [":foo", "@deps//:__all"],
+  classpath_dirs = ["src", "dev", "test"],
+  data = [])
 ```
 
-Behaves as you'd expect. Delegates to `java_binary` with `main_class clojure.main`.
+Like `java_binary`, the repl process runs from the bazel-bin package directory. Unlike the built-in java rules, it supports `classpath_dirs`, which allows adding directories to the classpath, like a conventional clojure repl.
 
 ### clojure_test
 

rules.bzl

@@ -1,4 +1,5 @@
 load("//rules:jar.bzl", _clojure_jar_impl = "clojure_jar_impl")
+load("//rules:repl.bzl", _clojure_repl_impl = "clojure_repl_impl")
 
 clojure_library = rule(
     doc = "Define a clojure library",
@@ -30,20 +31,19 @@ def clojure_binary(name, **kwargs):
                        runtime_deps = deps + runtime_deps,
                        **kwargs)
 
-def clojure_repl(name, deps=[], ns=None, **kwargs):
-    args = []
-
-    if ns:
-        args.extend(["-e", """\"(require '[{ns}]) (in-ns '{ns})\"""".format(ns = ns)])
-
-    args.extend(["-e", "(clojure.main/repl)"])
-
-    native.java_binary(name=name,
-                       runtime_deps=deps,
-                       jvm_flags=["-Dclojure.main.report=stderr"],
-                       main_class = "clojure.main",
-                       args = args,
-                       **kwargs)
+clojure_repl = rule(
+    doc = "Define a clojure repl",
+    attrs = {
+        "main_class": attr.string(),
+        "runtime_deps": attr.label_list(default = [], providers = [[JavaInfo]]),
+        "classpath_dirs": attr.label_list(default = [], allow_files = True),
+        "data": attr.label_list(default = [], allow_files = True),
+        "jvm_flags": attr.string_list(default=[], doc = "Optional jvm_flags to pass to the repl binary"),
+    },
+    executable = True,
+    provides = [],
+    toolchains = ["@bazel_tools//tools/jdk:toolchain_type"],
+    implementation = _clojure_repl_impl)
 
 def clojure_test(name, *, test_ns, deps=[], runtime_deps=[], **kwargs):
     # ideally the library name and the bin name would be the same. They can't be.

rules/repl.bzl

@@ -0,0 +1,36 @@
+### rule to start a clojure repl. We don't use `java_binary` because
+### we want to support adding directories to the classpath (and in the
+### future, possibly running from the source tree rather than `bazel-bin`), both in support of
+### `clj` live reloading semantics
+
+def clojure_repl_impl(ctx):
+
+    java_deps = depset(transitive = [d[JavaInfo].transitive_runtime_jars for d in ctx.attr.runtime_deps])
+
+    classpath_files = ["$BUILD_WORKSPACE_DIRECTORY/%s" % d.short_path for d in ctx.files.classpath_dirs]
+
+    jars = [d.short_path for d in java_deps.to_list()]
+
+    ## It's important that the dirs go ahead of jars, or live reloading breaks
+    classpath = classpath_files + jars
+    classpath_str = ":".join(classpath)
+
+    sh_file = ctx.actions.declare_file(ctx.attr.name)
+
+    runfiles = ctx.runfiles(files = ctx.files.data,
+                            transitive_files = java_deps)
+    runfiles.merge_all([d[DefaultInfo].default_runfiles for d in ctx.attr.runtime_deps])
+
+    default_info = DefaultInfo(executable=sh_file,
+                               runfiles = runfiles)
+
+    cmd = """java {jvm_flags} -cp {cp} {main_class} {args}""".format(cp=classpath_str,
+                                                                          main_class = ctx.attr.main_class,
+                                                                          args = " ".join(ctx.attr.args),
+                                                                          jvm_flags = " ".join(ctx.attr.jvm_flags))
+
+    ctx.actions.write(output=sh_file,
+                      content=cmd,
+                      is_executable=True)
+
+    return [ default_info ]

src/rules_clojure/gen_build.clj

@@ -868,10 +868,10 @@
                                                                                                        (cond-> m
                                                                                                          (seq (:deps m)) (update :deps (comp vec distinct))
                                                                                                          (:deps m) (update :deps (comp vec distinct))))))))))))))))))
-                          [(emit-bazel (list 'clojure_library (kwargs
+                          [(emit-bazel (list 'java_library (kwargs
                                                                {:name "__all"
-                                                                :deps (->> jar->lib
-                                                                           (mapv (comp library->label val)))})))]))
+                                                                :runtime_deps (->> jar->lib
+                                                                                   (mapv (comp library->label val)))})))]))
 
         :encoding "UTF-8"))