ghc-tags seems to choke on CPP ! negation

[juhp]

I often use CPP like:

#if !MIN_VERSION_simple_cmd_args(0,1,4)
: 

in my code which seems to trip up ghc-tags (I am using 1.5).

I get an error like:

ghc-tags -e

Common.hs:6:0: error:
     error: missing binary operator before token "("
        6 | #if !MIN_VERSION_http_directory(0,1,6)
          | 
  |
6 | #if !MIN_VERSION_http_directory(0,1,6)
  | ^

Common.hs:12:0: error:
 
    error: missing bQiunearry
y. hosp:eMr2aa4it:no.r0h :sb :eerror:f8o
:re 0  :t  o error:ke 
ne r
 "r (o "r 
:U  R meL ir. srh sosir: n: g 9  m:1bi2is0 ns:|ai  rnerror:#ygi  
fob pi !en Mra Iar Nty_o  VroeE prRberSeroIfarOot:Nro _ermh  ittbstoespkfi_eondnrgi e r" be(tic"ont
kaoerr nyy   ( "o0 (p,"e1 
r, a6  t)2 o
4 r    |b   e # f i of r  8e !   M|t I o N#k _ie|Vfn E  
R!"SM(II" ON
 N_ _V |sE 
iR mS 1pI2lO  eN |__ cs  mi9dm #(p|0l i,e#f2_i ,cf!0m M)dMI
_INaN_ r_V gVE sER (RS0SI ,IO 1ON ,N_ 4_h )ht 
tt|tp  p_
 _d di ir re  ec  ct| to
 or ry2 y(4|(0  0,|
,11, ,6 9)# )
|
i
 f   8  !  |M| I N  ^_ 
V# E Ri Sf I |
O! NM
_IsNi_ mVC pEo|lRm
eSm_Io9cOn mN.|d_h(ss 0i:,m#2p1,l6i0e:f)_ 
c0Mm:I d N _error:_ aV|r
EgR s S^( I
0 O, N1_, h4et)rt
rQuery.hs:1:1: error:
    `gcc' failed in phase `C pre-processor'. (Exit code: 1)
po_ rd :i| rme ic^st
soirnyg( 0
b,i1n,aM9ra)yi
 no. ph es|r:a t1^o6
r: b0e:f 
oerror:re
 UtR oL k. eh ns : "e(3r"3r
:or 0: :   m error:is 
s i  n1 g6    b|i  n#eairrfry o MroI:pN e_mrViaEstRsoSirIn OgbN e_bfsioinrmaepr lyte o_okcpemendr (a"0t(,o"2r
, 0b )e 
f o  r e     t o1 k6 e  n|    "# (i|"f 
 
! M I  N  _ V| E
 R S13I63O  N||_ s #iim#fp li!efM_ IcMNmI_dNV__EaVRrESgRIsSO(IN0O_,Nh1_t,st7ip)m_
pdli er _e cc mtdo (r 0y ,( 20 ,, 01|), 
9
) 
     |   |  
^
 1 6   | 
  | #
if   ! M|I
N_3V3E R|SIC OoNm#_msoiinfm. ph!lsMe:I_Nc2_m5Vd:E_Ra0Sr:Ig Oserror:N(_0h
,t1t ,p 7_ )d 
ir  ee cr tr|oorr y:^( 
0m,i1s,s9i
)n
g M ba ii nn|a.rh ys^ :
op2e4r:aURL.hs:1:1: error:
    `gcc' failed in phase `C pre-processor'. (Exit code: 1)
t0o:r  error:be
fo r e   to keernr o"r(:" 
mi s s i ng   b i2n5a r|y  #oipfe r!aMtIoNr_ VbEeRfSoIrOeN _thotktepn_ d"i(r"e
ct o r y (0 , 1 ,264) 
|  # i f  ! M I N _ V E|R S
ION _ s i|m
pl2e5_ c|md _a#rgisf( 0!,M1I,N7_)V
ER S I O N_ h t t p _ d|i r
ect o r y|(
0,214, 6|)
  #  i|f  !^M
IN_VERSION_simple_cCommon.hs:1:1: error:
md    `gcc' failed in phase `C pre-processor'. (Exit code: 1)
_args(0,1,7)
   | ^
Main.hs:1:1: error:
    `gcc' failed in phase `C pre-processor'. (Exit code: 1)

which is quite "interesting". :)

If you want to reproduce this is with https://github.com/juhp/fedora-repoquery but I don't think that particularly matters.

[arybczak]

You need to add these defines to ghc-tags.yaml, like

cpp_options:
- -DMIN_VERSION_http_directory(x,y,z)=1

since ghc-tags doesn't know about these (perhaps it could get support for including a file generated by cabal that has these defines, PRs welcome).

The garbled output is an unfortunate consequence of multithreading + GHC calling gcc for preprocessing, I can't do much about this since I can't control gcc's output. If you want readable output in case of errors to figure out which defines you need to add to the configuration, temporarily pass -j1 to ghc-tags.

[juhp]

(perhaps it could get support for including a file generated by cabal that has these defines, PRs welcome).

Not really sure how to teach it to look for cabal_macros.h under dist, dist-newstyle, or .stack-work?

[arybczak]

Yeah, me neither to be fair 😞