Merge pull request #51 from gasche/better-errors

Better errors

CHANGES.md

@@ -1,6 +1,9 @@
 ### 3.2.0
 
-* Improve parsing errors by adding locations (@gasche, #47)
+* Improve error messages (@gasche, #47 and #51)
+  Note: the exceptions raised by Mustache have changed, this breaks
+  compatibility for users that would catch and deconstruct existing
+  exceptions.
 * Add `render_buf` to render templates directly to buffers (@gasche, #48)
 * When a lookup fails in the current context, lookup in parents contexts.
   This should fix errors when using "{{#foo}}" for a scalar variable

bin/mustache_cli.ml

@@ -1,12 +1,27 @@
-let apply_mustache json_data template_data =
+module Mustache = struct
+  include Mustache
+  include With_locations
+end
+
+let apply_mustache ~json_data ~template_filename ~template_data =
   let env = Ezjsonm.from_string json_data
   and tmpl =
-    try Mustache.of_string template_data
-    with Mustache.Parse_error err ->
-      Format.eprintf "%a@." Mustache.pp_error err;
+    let lexbuf = Lexing.from_string template_data in
+    let () =
+      let open Lexing in
+      lexbuf.lex_curr_p <- { lexbuf.lex_curr_p with pos_fname = template_filename };
+    in
+    try Mustache.parse_lx lexbuf
+    with Mustache.Template_parse_error err ->
+      Format.eprintf "Template parse error:@\n%a@."
+        Mustache.pp_template_parse_error err;
       exit 3
   in
-  Mustache.render tmpl env |> print_endline
+  try Mustache.render tmpl env |> print_endline
+  with Mustache.Render_error err ->
+    Format.eprintf "Template render error:@\n%a@."
+      Mustache.pp_render_error err;
+    exit 2
 
 let load_file f =
   let ic = open_in f in
@@ -17,10 +32,10 @@ let load_file f =
   (Bytes.to_string s)
 
 let run json_filename template_filename =
-  let j = load_file json_filename
-  and t = load_file template_filename
+  let json_data = load_file json_filename
+  and template_data = load_file template_filename
   in
-  apply_mustache j t
+  apply_mustache ~json_data ~template_filename ~template_data
 
 let usage () =
   print_endline "Usage: mustache-cli json_filename template_filename"

bin/test/errors/parsing-errors.t

@@ -4,61 +4,73 @@ Delimiter problems:
   $ PROBLEM=no-closing-mustache.mustache
   $ echo "{{foo" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Line 2, character 0: syntax error.
+  Template parse error:
+  File "no-closing-mustache.mustache", line 2, character 0: syntax error.
   [3]
 
   $ PROBLEM=one-closing-mustache.mustache
   $ echo "{{foo}" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Lines 1-2, characters 6-0: syntax error.
+  Template parse error:
+  File "one-closing-mustache.mustache", lines 1-2, characters 6-0:
+  syntax error.
   [3]
 
   $ PROBLEM=eof-before-variable.mustache
   $ echo "{{" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Line 2, character 0: ident expected.
+  Template parse error:
+  File "eof-before-variable.mustache", line 2, character 0: ident expected.
   [3]
 
   $ PROBLEM=eof-before-section.mustache
   $ echo "{{#" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Line 2, character 0: ident expected.
+  Template parse error:
+  File "eof-before-section.mustache", line 2, character 0: ident expected.
   [3]
 
   $ PROBLEM=eof-before-section-end.mustache
   $ echo "{{#foo}} {{.}} {{/" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Line 2, character 0: ident expected.
+  Template parse error:
+  File "eof-before-section-end.mustache", line 2, character 0: ident expected.
   [3]
 
   $ PROBLEM=eof-before-inverted-section.mustache
   $ echo "{{^" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Line 2, character 0: ident expected.
+  Template parse error:
+  File "eof-before-inverted-section.mustache", line 2, character 0:
+  ident expected.
   [3]
 
   $ PROBLEM=eof-before-unescape.mustache
   $ echo "{{{" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Line 2, character 0: ident expected.
+  Template parse error:
+  File "eof-before-unescape.mustache", line 2, character 0: ident expected.
   [3]
 
   $ PROBLEM=eof-before-unescape.mustache
   $ echo "{{&" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Line 2, character 0: ident expected.
+  Template parse error:
+  File "eof-before-unescape.mustache", line 2, character 0: ident expected.
   [3]
 
   $ PROBLEM=eof-before-partial.mustache
   $ echo "{{>" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Line 2, character 0: ident expected.
+  Template parse error:
+  File "eof-before-partial.mustache", line 2, character 0: ident expected.
   [3]
 
   $ PROBLEM=eof-in-comment.mustache
   $ echo "{{! non-terminated comment" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Line 2, character 0: non-terminated comment.
+  Template parse error:
+  File "eof-in-comment.mustache", line 2, character 0: non-terminated comment.
   [3]
 
 
@@ -67,13 +79,15 @@ Mismatches between opening and closing mustaches:
   $ PROBLEM=two-three.mustache
   $ echo "{{ foo }}}" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Lines 1-2, characters 10-0: syntax error.
+  Template parse error:
+  File "two-three.mustache", lines 1-2, characters 10-0: syntax error.
   [3]
 
   $ PROBLEM=three-two.mustache
   $ echo "{{{ foo }}" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Lines 1-2, characters 10-0: syntax error.
+  Template parse error:
+  File "three-two.mustache", lines 1-2, characters 10-0: syntax error.
   [3]
 
 
@@ -82,17 +96,22 @@ Mismatch between section-start and section-end:
   $ PROBLEM=foo-bar.mustache
   $ echo "{{#foo}} {{.}} {{/bar}}" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Fatal error: exception Mustache_types.Invalid_template("Mismatched section foo with bar")
-  [2]
+  Template parse error:
+  File "foo-bar.mustache", lines 1-2, characters 23-0:
+  Section mismatch: {{#foo}} is closed by {{/bar}}.
+  [3]
 
   $ PROBLEM=foo-not-closed.mustache
   $ echo "{{#foo}} {{.}} {{foo}}" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Line 2, character 0: syntax error.
+  Template parse error:
+  File "foo-not-closed.mustache", line 2, character 0: syntax error.
   [3]
 
   $ PROBLEM=wrong-nesting.mustache
   $ echo "{{#bar}} {{#foo}} {{.}} {{/bar}} {{/foo}}" > $PROBLEM
   $ mustache foo.json $PROBLEM
-  Fatal error: exception Mustache_types.Invalid_template("Mismatched section foo with bar")
-  [2]
+  Template parse error:
+  File "wrong-nesting.mustache", lines 1-2, characters 41-0:
+  Section mismatch: {{#foo}} is closed by {{/bar}}.
+  [3]

bin/test/errors/render-errors.t/run.t

@@ -27,49 +27,69 @@ one possible source of error, or both, or none.
 Invalid variable name:
 
   $ mustache reference.json missing-variable.mustache
-  Fatal error: exception Mustache_types.Missing_variable("na")
+  Template render error:
+  File "missing-variable.mustache", line 14, characters 40-46:
+  the variable 'na' is missing.
   [2]
 
   $ mustache missing-variable.json reference.mustache
-  Fatal error: exception Mustache_types.Missing_variable("data")
+  Template render error:
+  File "reference.mustache", line 5, characters 4-12:
+  the variable 'data' is missing.
   [2]
 
 Invalid section name:
 
   $ mustache reference.json missing-section.mustache
-  Fatal error: exception Mustache_types.Missing_section("na")
+  Template render error:
+  File "missing-section.mustache", line 14, characters 0-55:
+  the section 'na' is missing.
   [2]
 
   $ mustache missing-section.json reference.mustache
-  Fatal error: exception Mustache_types.Missing_section("group")
+  Template render error:
+  File "reference.mustache", lines 9-12, characters 0-10:
+  the section 'group' is missing.
   [2]
 
 Error in a dotted path foo.bar (one case for the first component, the other in the second).
 
   $ mustache reference.json invalid-dotted-name-1.mustache
-  Fatal error: exception Mustache_types.Missing_variable("gro")
+  Template render error:
+  File "invalid-dotted-name-1.mustache", line 10, characters 2-15:
+  the variable 'gro' is missing.
   [2]
 
   $ mustache invalid-dotted-name-1.json reference.mustache
-  Fatal error: exception Mustache_types.Missing_section("group")
+  Template render error:
+  File "reference.mustache", lines 9-12, characters 0-10:
+  the section 'group' is missing.
   [2]
 
   $ mustache reference.json invalid-dotted-name-2.mustache
-  Fatal error: exception Mustache_types.Missing_variable("fir")
+  Template render error:
+  File "invalid-dotted-name-2.mustache", line 10, characters 2-15:
+  the variable 'group.fir' is missing.
   [2]
 
   $ mustache invalid-dotted-name-2.json reference.mustache
-  Fatal error: exception Mustache_types.Missing_variable("first")
+  Template render error:
+  File "reference.mustache", line 10, characters 2-17:
+  the variable 'group.first' is missing.
   [2]
 
 Non-scalar used as a scalar:
 
   $ mustache reference.json non-scalar.mustache
-  Fatal error: exception Mustache_types.Invalid_param("Lookup.scalar: not a scalar")
+  Template render error:
+  File "non-scalar.mustache", line 4, characters 0-8:
+  the value of 'list' is not a valid scalar.
   [2]
 
   $ mustache non-scalar.json reference.mustache
-  Fatal error: exception Mustache_types.Invalid_param("Lookup.scalar: not a scalar")
+  Template render error:
+  File "reference.mustache", line 1, characters 7-16:
+  the value of 'title' is not a valid scalar.
   [2]
 
 Missing partial (currently the CLI does not support any partial anyway):
@@ -78,5 +98,7 @@ Missing partial (currently the CLI does not support any partial anyway):
 in better `ls` output).
 
   $ mustache reference.json z-missing-partial.mustache
-  Fatal error: exception Mustache_types.Missing_partial("second")
+  Template render error:
+  File "z-missing-partial.mustache", line 11, characters 2-13:
+  the partial 'second' is missing.
   [2]