disable color in docstring format tests since it breaks in different environments in CI

Author: zth

tests/tools_tests/src/expected/FormatDocstringsTestError.res.expected

@@ -2,10 +2,10 @@
   Syntax error in code block in docstring
   FormatDocstringsTestError.res:5:10-6:3
 
-  3 │ 
-  4 │ 
-  5 │ let name= 
-  6 │ let x=12
+  3 │ 
+  4 │ 
+  5 │ let name= 
+  6 │ let x=12
 
   This let-binding misses an expression
 

tests/tools_tests/test.sh

@@ -19,7 +19,7 @@ done
 # Test format-docstrings command
 for file in src/docstrings-format/*.{res,resi}; do
   output="src/expected/$(basename $file).expected"
-  ../../_build/install/default/bin/rescript-tools format-docstrings "$file" --stdout > $output
+  DISABLE_COLOR=true ../../_build/install/default/bin/rescript-tools format-docstrings "$file" --stdout > $output
   # # CI. We use LF, and the CI OCaml fork prints CRLF. Convert.
   if [ "$RUNNER_OS" == "Windows" ]; then
     perl -pi -e 's/\r\n/\n/g' -- $output

tools/bin/main.ml

@@ -54,6 +54,11 @@ let main () =
       logAndExit (Tools.extractDocs ~entryPointFile:path ~debug:false)
     | _ -> logAndExit (Error docHelp))
   | "format-docstrings" :: rest -> (
+    (try
+       match Sys.getenv "DISABLE_COLOR" with
+       | "true" -> Clflags.color := Some Misc.Color.Never
+       | _ -> ()
+     with Not_found -> ());
     match rest with
     | ["-h"] | ["--help"] -> logAndExit (Ok formatDocstringsHelp)
     | [path; "--stdout"] -> (

tools/src/tools.ml

@@ -764,7 +764,7 @@ module FormatDocstrings = struct
                 ~display_filename:displayFilename ~source:codeWithOffset
             in
             if invalid then (
-              let buf = Buffer.create 32 in
+              let buf = Buffer.create 1000 in
               let formatter = Format.formatter_of_buffer buf in
               Res_diagnostics.print_report ~formatter
                 ~custom_intro:(Some "Syntax error in code block in docstring")